╭─── Claude Code v2.1.63 ────────────────────────────────────────────────────────────────────────────────────────────────╮ │ │ Tips for getting started │ │ Welcome back John! │ Run /init to create a CLAUDE.md file with instructions for Claude │ │ │ ───────────────────────────────────────────────────────────────── │ │ │ Recent activity │ │ ▐▛███▜▌ │ No recent activity │ │ ▝▜█████▛▘ │ │ │ ▘▘ ▝▝ │ │ │ Sonnet 4.6 · Claude Pro · John Slankas │ │ │ ~/…/claude_code_workshop/exercise_one/walkthrough │ │ ╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯ ❯ Prompt 1 — Create project files and test harness ```text You are implementing the project in a folder `temp-anomaly/` with the required structure. Task (TDD-first): 1) Create: - requirements.txt containing ONLY these dev deps (pinned not required): pytest, pytest-cov, black, ruff, mypy, pre-commit - temp_anomaly.py (can be minimal placeholder) - tests/ directory with an initial test file tests/test_smoke.py - README.md and AGENTS.md as placeholders (you will expand them later) 2) In tests/test_smoke.py write a test that runs `python temp_anomaly.py` with no args using subprocess.run, capturing stdout/stderr. - Assert returncode == 1 - Assert stdout == "Usage: python temp_anomaly.py \n" - Assert stderr == "" (must be empty) 3) Implement the minimal temp_anomaly.py to satisfy the test: - Exactly one positional arg required; otherwise print usage to stdout only and exit 1. - Do not write to stderr. Constraints: - Python 3.12+ - Keep code small; no extra features yet. Human validation: - Run: pytest -q - Run manually: python temp_anomaly.py Expected: prints usage line to stdout and exits 1. ⎿ ⧉ Selected 29 lines from prompt_plan.md in Visual Studio Code ⏺ Read 1 file (ctrl+o to expand) ⏺ Bash(mkdir -p /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly/tests) ⎿ Done ⏺ Write(requirements.txt) ⎿ Wrote 6 lines to requirements.txt 1 pytest 2 pytest-cov 3 black 4 ruff 5 mypy 6 pre-commit ⏺ Write(temp_anomaly.py) ⎿ Wrote 11 lines to temp_anomaly.py 1 import sys 2 3 4 def main() -> None: 5 if len(sys.argv) != 2: 6 print("Usage: python temp_anomaly.py ") 7 sys.exit(1) 8 9 10 if __name__ == "__main__": … +1 line (ctrl+o to expand) ⏺ Write(tests/test_smoke.py) ⎿ Wrote 16 lines to tests/test_smoke.py 1 import subprocess 2 import sys 3 from pathlib import Path 4 5 SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 6 7 8 def test_no_args_prints_usage_and_exits_1(): 9 result = subprocess.run( 10 [sys.executable, str(SCRIPT)], … +6 lines (ctrl+o to expand) ⏺ Write(README.md) ⎿ Wrote 3 lines to README.md 1 # temp-anomaly 2 3 Placeholder — to be expanded. ⏺ Write(AGENTS.md) ⎿ Wrote 3 lines to AGENTS.md 1 # AGENTS 2 3 Placeholder — to be expanded. ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && pytest -q 2>&1) ⎿ Error: Exit code 127 (eval):1: command not found: pytest (eval):1: command not found: pytest ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python -m pytest -q 2>&1) ⎿ Error: Exit code 127 (eval):1: command not found: python (eval):1: command not found: python ⏺ Bash(which python3 && python3 --version) ⎿ /Library/Frameworks/Python.framework/Versions/3.11/bin/python3 Python 3.11.9 ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ . [100%] 1 passed in 0.04s ⏺ All files created and the test passes. Here's what was built: Project structure: temp-anomaly/ ├── requirements.txt # pytest, pytest-cov, black, ruff, mypy, pre-commit ├── temp_anomaly.py # minimal CLI entry point ├── tests/ │ └── test_smoke.py # subprocess test asserting usage + exit code ├── README.md # placeholder └── AGENTS.md # placeholder How it works: - temp_anomaly.py checks len(sys.argv) != 2 — if not exactly one positional arg, it prints the usage line to stdout only and exits with code 1 - test_smoke.py runs the script via subprocess.run and asserts returncode == 1, correct stdout, and empty stderr ✻ Churned for 35s ❯ Add file opening behavior with correct error message. TDD: 1) Create tests/test_file_errors.py with a subprocess test: - Run: python temp_anomaly.py does_not_exist.csv - Assert returncode == 1 - Assert stdout == "ERROR: Cannot open file 'does_not_exist.csv'\n" - Assert stderr == "" 2) Implement in temp_anomaly.py: - If exactly one arg is given, attempt to open that file path. - If open fails (OSError / FileNotFoundError), print exactly: ERROR: Cannot open file '' to stdout, newline, exit 1. Do NOT implement decoding rules yet; just opening. Human validation: - pytest -q - python temp_anomaly.py does_not_exist.csv ⎿ ⧉ Selected 20 lines from ../prompt_plan.md in Visual Studio Code ⏺ Write(tests/test_file_errors.py) ⎿ Wrote 16 lines to tests/test_file_errors.py 1 import subprocess 2 import sys 3 from pathlib import Path 4 5 SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 6 7 8 def test_missing_file_prints_error_and_exits_1(): 9 result = subprocess.run( 10 [sys.executable, str(SCRIPT), "does_not_exist.csv"], … +6 lines (ctrl+o to expand) ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(temp_anomaly.py) ⎿ Added 7 lines 6 print("Usage: python temp_anomaly.py ") 7 sys.exit(1) 8 9 + path = sys.argv[1] 10 + try: 11 + open(path).close() 12 + except OSError: 13 + print(f"ERROR: Cannot open file '{path}'") 14 + sys.exit(1) 15 16 + 17 if __name__ == "__main__": 18 main() ⏺ Bash(python3 -m pytest -q 2>&1) ⎿ .. [100%] 2 passed in 0.06s ⏺ Both tests pass. The new behavior: - Opens the file if one arg is provided; on any OSError prints ERROR: Cannot open file '' to stdout and exits 1 - No stderr output in either failure case ❯ commit prompts 1 and 2 ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough && git status && git diff --stat) ⎿ On branch main Your branch is up to date with 'origin/main'. … +12 lines (ctrl+o to expand) ⏺ Bash(git add temp-anomaly/ && git status) ⎿ On branch main Your branch is up to date with 'origin/main'. … +26 lines (ctrl+o to expand) ⏺ I'll skip the __pycache__ files and add a .gitignore first. ⏺ Bash(git rm --cached temp-anomaly/tests/__pycache__/test_file_errors.cpython-311-pytest-9.0.2.pyc temp-anomaly/tests/__pycache__/test_smoke.cpython-311-pytest-9.0.2.…) ⎿ rm 'exercise_one/walkthrough/temp-anomaly/tests/__pycache__/test_file_errors.cpython-311-pytest-9.0.2.pyc' rm 'exercise_one/walkthrough/temp-anomaly/tests/__pycache__/test_smoke.cpython-311-pytest-9.0.2.pyc' ⏺ Write(.gitignore) ⎿ Wrote 6 lines to .gitignore 1 __pycache__/ 2 *.pyc 3 .mypy_cache/ 4 .ruff_cache/ 5 .coverage 6 htmlcov/ ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git status) ⎿ On branch main Your branch is up to date with 'origin/main'. … +25 lines (ctrl+o to expand) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git commit -m "$(cat <<'EOF' Add temp-anomaly project scaffold (prompts 1 & 2)…) ⎿ [main 2455dc9] Add temp-anomaly project scaffold (prompts 1 & 2) 7 files changed, 68 insertions(+) create mode 100644 exercise_one/walkthrough/temp-anomaly/.gitignore … +6 lines (ctrl+o to expand) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 2455dc9 — 7 files, prompts 1 & 2. ❯ Implement UTF-8 decoding with optional BOM and correct decode-failure handling. TDD: 1) In tests/test_file_errors.py add a test that creates a temporary file containing invalid UTF-8 bytes. - Use pytest tmp_path to create e.g. bad.csv - Write bytes like b"\xff\xfe\xff" - Run subprocess: python temp_anomaly.py - Assert returncode == 1 - Assert stdout == "ERROR: Cannot decode file '' as UTF-8\n" where is the basename (match exactly what the script prints; use the argv string you pass). - Assert stderr == "" 2) Implement: - Open the file in binary, decode as 'utf-8-sig' (or open text with encoding='utf-8-sig'). - If UnicodeDecodeError occurs, print the exact error string and exit 1. Do not parse CSV yet. Human validation: - pytest -q ⎿ ⧉ Selected 20 lines from prompt_plan.md in Visual Studio Code ⏺ Read 2 files (ctrl+o to expand) ⏺ Update(tests/test_file_errors.py) ⎿ Added 13 lines 5 SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 6 7 8 +def test_invalid_utf8_prints_error_and_exits_1(tmp_path): 9 + bad_csv = tmp_path / "bad.csv" 10 + bad_csv.write_bytes(b"\xff\xfe\xff") 11 + result = subprocess.run( 12 + [sys.executable, str(SCRIPT), str(bad_csv)], 13 + capture_output=True, 14 + text=True, 15 + ) 16 + assert result.returncode == 1 17 + assert result.stdout == f"ERROR: Cannot decode file '{bad_csv}' as UTF-8\n" 18 + assert result.stderr == "" 19 + 20 + 21 def test_missing_file_prints_error_and_exits_1(): 22 result = subprocess.run( 23 [sys.executable, str(SCRIPT), "does_not_exist.csv"], ⏺ Update(temp_anomaly.py) ⎿ Added 5 lines, removed 1 line 8 9 path = sys.argv[1] 10 try: 11 - open(path).close() 11 + with open(path, encoding="utf-8-sig") as f: 12 + f.read() 13 except OSError: 14 print(f"ERROR: Cannot open file '{path}'") 15 sys.exit(1) 16 + except UnicodeDecodeError: 17 + print(f"ERROR: Cannot decode file '{path}' as UTF-8") 18 + sys.exit(1) 19 20 21 if __name__ == "__main__": ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ... [100%] 3 passed in 0.11s ⏺ All 3 tests pass. The implementation now: - Opens files with encoding="utf-8-sig" (handles optional BOM transparently) - Reads the full content to trigger any UnicodeDecodeError - Prints the exact error message to stdout and exits 1 ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add UTF-8 decoding wi…) ⎿ [main 319fc7f] Add UTF-8 decoding with BOM support and decode-error handling (prompt 3) 2 files changed, 18 insertions(+), 1 deletion(-) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 319fc7f. ❯ Implement header detection per spec: - A header row is the first parseable CSV row containing at least two columns. - If the file is empty/whitespace/has fewer than two columns total, it's a schema error: "ERROR: Missing header row" exit code 2. TDD: 1) Add tests/test_schema_validation.py: - Case A: empty file -> exit 2, stdout == "ERROR: Missing header row\n" - Case B: file with only whitespace lines -> same - Case C: file with a single-column row like "onlyone\n" -> same All via subprocess, assert stderr == "". 2) Implement minimal CSV reading: - Use csv.reader over text opened with encoding='utf-8-sig' - Find the first row where len(row) >= 2 => that's the header - If never found => print error and exit 2 Do not validate required columns yet. Human validation: - pytest -q ⎿ ⧉ Selected 21 lines from prompt_plan.md in Visual Studio Code ⏺ Write(tests/test_schema_validation.py) ⎿ Wrote 42 lines to tests/test_schema_validation.py 1 import subprocess 2 import sys 3 from pathlib import Path 4 5 SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 6 7 MISSING_HEADER = "ERROR: Missing header row\n" 8 9 10 def run(path: Path): … +32 lines (ctrl+o to expand) ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(temp_anomaly.py) ⎿ Added 14 lines, removed 2 lines 1 +import csv 2 import sys 3 4 ... 9 10 path = sys.argv[1] 11 try: 11 - with open(path, encoding="utf-8-sig") as f: 12 - f.read() 12 + f = open(path, encoding="utf-8-sig", newline="") 13 except OSError: 14 print(f"ERROR: Cannot open file '{path}'") 15 sys.exit(1) 16 + 17 + try: 18 + header = next( 19 + (row for row in csv.reader(f) if len(row) >= 2), 20 + None, 21 + ) 22 except UnicodeDecodeError: 23 print(f"ERROR: Cannot decode file '{path}' as UTF-8") 24 sys.exit(1) 25 + finally: 26 + f.close() 27 28 + if header is None: 29 + print("ERROR: Missing header row") 30 + sys.exit(2) 31 32 + 33 if __name__ == "__main__": 34 main() ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ...... [100%] 6 passed in 0.18s ⏺ All 6 tests pass. The implementation scans CSV rows with csv.reader, finds the first row with len(row) >= 2 as the header, and exits 2 with the error message if none is found. ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add header detection…) ⎿ [main 34b6c4f] Add header detection with missing-header schema error (prompt 4) 2 files changed, 56 insertions(+), 2 deletions(-) create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_schema_validation.py ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 34b6c4f. ❯ Add required column resolution for Date and Temperature. TDD: 1) Extend tests/test_schema_validation.py with subprocess tests: - Valid headers: "Date,Temperature\n" (should proceed further; for now you can exit 0 after schema passes) " DATE , TEMPERATURE \n" (trimming) "date,temperature\n" (case-insensitive) For these, since no further behavior exists yet, require: - exit code == 0 - stdout starts with "TEMPERATURE ANOMALY REPORT\n" (you can print only that line for now) - stderr == "" 2) Add missing column tests: - Header "Date,Temp\n" -> exit 2 and stdout == "ERROR: Missing required column 'Temperature'\n" - Header "Temperature,Value\n" -> exit 2 and stdout == "ERROR: Missing required column 'Date'\n" Implementation notes: - Trim header cells - Compare lowercased to 'date' and 'temperature' - If missing: exact error above, exit 2 - If schema ok: print "TEMPERATURE ANOMALY REPORT" line and exit 0 for now. Human validation: - pytest -q ⎿ ⧉ Selected 25 lines from prompt_plan.md in Visual Studio Code ⏺ Read 2 files (ctrl+o to expand) ⏺ Update(tests/test_schema_validation.py) ⎿ Added 49 lines 40 assert result.returncode == 2 41 assert result.stdout == MISSING_HEADER 42 assert result.stderr == "" 43 + 44 + 45 +# --- valid header variants --- 46 + 47 +def test_valid_header_exact(tmp_path): 48 + f = tmp_path / "data.csv" 49 + f.write_text("Date,Temperature\n") 50 + result = run(f) 51 + assert result.returncode == 0 52 + assert result.stdout.startswith("TEMPERATURE ANOMALY REPORT\n") 53 + assert result.stderr == "" 54 + 55 + 56 +def test_valid_header_trimmed(tmp_path): 57 + f = tmp_path / "data.csv" 58 + f.write_text(" DATE , TEMPERATURE \n") 59 + result = run(f) 60 + assert result.returncode == 0 61 + assert result.stdout.startswith("TEMPERATURE ANOMALY REPORT\n") 62 + assert result.stderr == "" 63 + 64 + 65 +def test_valid_header_lowercase(tmp_path): 66 + f = tmp_path / "data.csv" 67 + f.write_text("date,temperature\n") 68 + result = run(f) 69 + assert result.returncode == 0 70 + assert result.stdout.startswith("TEMPERATURE ANOMALY REPORT\n") 71 + assert result.stderr == "" 72 + 73 + 74 +# --- missing required columns --- 75 + 76 +def test_missing_temperature_column(tmp_path): 77 + f = tmp_path / "data.csv" 78 + f.write_text("Date,Temp\n") 79 + result = run(f) 80 + assert result.returncode == 2 81 + assert result.stdout == "ERROR: Missing required column 'Temperature'\n" 82 + assert result.stderr == "" 83 + 84 + 85 +def test_missing_date_column(tmp_path): 86 + f = tmp_path / "data.csv" 87 + f.write_text("Temperature,Value\n") 88 + result = run(f) 89 + assert result.returncode == 2 90 + assert result.stdout == "ERROR: Missing required column 'Date'\n" 91 + assert result.stderr == "" ⏺ Update(temp_anomaly.py) ⎿ Added 8 lines 29 print("ERROR: Missing header row") 30 sys.exit(2) 31 32 + cols = [c.strip().lower() for c in header] 33 + for required, label in (("date", "Date"), ("temperature", "Temperature")): 34 + if required not in cols: 35 + print(f"ERROR: Missing required column '{label}'") 36 + sys.exit(2) 37 38 + print("TEMPERATURE ANOMALY REPORT") 39 + 40 + 41 if __name__ == "__main__": 42 main() ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ........... [100%] 11 passed in 0.33s ⏺ All 11 tests pass. The implementation strips and lowercases header cells, checks for both date and temperature, and prints TEMPERATURE ANOMALY REPORT on success. ❯ commit ⎿ ⧉ Selected 16 lines from ../prompt_plan.md in Visual Studio Code ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add required column v…) ⎿ [main bd23211] Add required column validation for Date and Temperature (prompt 5) 2 files changed, 57 insertions(+) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as bd23211. ❯ Detect multiple columns matching Date or Temperature (case-insensitive), as a fatal schema error with exit code 2. TDD: 1) In tests/test_schema_validation.py add: - Header "Date,DATE,Temperature\n" -> exit 2 and stdout == "ERROR: Duplicate column 'Date'\n" - Header "Date,Temperature,TEMPERATURE\n" -> exit 2 and stdout == "ERROR: Duplicate column 'Temperature'\n" stderr must be empty. 2) Implement: - When scanning headers, count matches for each required column. - If match count > 1, print exact duplicate message, exit 2. Keep previous behaviors intact. Human validation: - pytest -q ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(tests/test_schema_validation.py) ⎿ Added 20 lines 89 assert result.returncode == 2 90 assert result.stdout == "ERROR: Missing required column 'Date'\n" 91 assert result.stderr == "" 92 + 93 + 94 +# --- duplicate columns --- 95 + 96 +def test_duplicate_date_column(tmp_path): 97 + f = tmp_path / "data.csv" 98 + f.write_text("Date,DATE,Temperature\n") 99 + result = run(f) 100 + assert result.returncode == 2 101 + assert result.stdout == "ERROR: Duplicate column 'Date'\n" 102 + assert result.stderr == "" 103 + 104 + 105 +def test_duplicate_temperature_column(tmp_path): 106 + f = tmp_path / "data.csv" 107 + f.write_text("Date,Temperature,TEMPERATURE\n") 108 + result = run(f) 109 + assert result.returncode == 2 110 + assert result.stdout == "ERROR: Duplicate column 'Temperature'\n" 111 + assert result.stderr == "" ⏺ Update(temp_anomaly.py) ⎿ Added 5 lines, removed 1 line 31 32 cols = [c.strip().lower() for c in header] 33 for required, label in (("date", "Date"), ("temperature", "Temperature")): 34 - if required not in cols: 34 + count = cols.count(required) 35 + if count > 1: 36 + print(f"ERROR: Duplicate column '{label}'") 37 + sys.exit(2) 38 + if count == 0: 39 print(f"ERROR: Missing required column '{label}'") 40 sys.exit(2) 41 ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ............. [100%] 13 passed in 0.38s ⏺ All 13 tests pass. Duplicate detection checks cols.count(required) > 1 before the missing check, so duplicate errors take priority. ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Detect duplicate Date…) ⎿ [main 8a79a85] Detect duplicate Date/Temperature columns as schema error (prompt 6) 2 files changed, 25 insertions(+), 1 deletion(-) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 8a79a85. ❯ Introduce row parsing rules and the DATA ISSUES section, but no ordering/anomalies/chart yet. TDD: 1) Add tests/test_missing_values.py with a subprocess test using a CSV fixture like: Date,Temperature,Extra 2026-01-01,72.0,x 2026-01-02 (malformed row: fewer columns than header count) 2026-02-30,70.0,x (invalid date) 2026-01-04,seventy,x (non-numeric temp) 2026-01-05,nan,x (NaN invalid) 2026-01-06,inf,x (+inf invalid) 2026-01-07,-inf,x (-inf invalid) 2026-01-08,73.0,x Expected (for now): program exits 0 and prints these sections in exact order: TEMPERATURE ANOMALY REPORT ASCII CHART ANOMALIES DATA ISSUES For now, ASCII CHART can be empty (no rows yet), and ANOMALIES can print "(none)". But DATA ISSUES must list entries in ascending line order (line numbers include header line as 1): Line 3: malformed row Line 4: invalid date: 2026-02-30 Line 5: non-numeric temperature: seventy Line 6: non-numeric temperature: nan Line 7: non-numeric temperature: inf Line 8: non-numeric temperature: -inf Each on its own line. 2) Implement: - Malformed row: len(row) < header_column_count => data issue - Date parse: YYYY-MM-DD using datetime.date.fromisoformat after validating structure; impossible dates invalid - Temp parse: float(value) then reject non-finite via math.isfinite - Trim cell values - Record issues as strings; do not include invalid rows in later processing - Emit the 4 required section headers always (even if content minimal) Human validation: - pytest -q - Run script on the fixture and visually confirm DATA ISSUES formatting. ⎿ ⧉ Selected 43 lines from prompt_plan.md in Visual Studio Code ⏺ Write(tests/test_missing_values.py) ⎿ Wrote 44 lines to tests/test_missing_values.py 1 import subprocess 2 import sys 3 from pathlib import Path 4 5 SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 6 7 FIXTURE = """\ 8 Date,Temperature,Extra 9 2026-01-01,72.0,x 10 2026-01-02 … +34 lines (ctrl+o to expand) ⏺ Now rewrite temp_anomaly.py to implement the full row-parsing logic: ⏺ Write(temp_anomaly.py) ⎿ Added 52 lines, removed 9 lines 1 import csv 2 +import math 3 import sys 4 +from datetime import date 5 6 7 def main() -> None: ... 11 12 path = sys.argv[1] 13 try: 12 - f = open(path, encoding="utf-8-sig", newline="") 14 + with open(path, encoding="utf-8-sig", newline="") as f: 15 + rows = list(csv.reader(f)) 16 except OSError: 17 print(f"ERROR: Cannot open file '{path}'") 18 sys.exit(1) 16 - 17 - try: 18 - header = next( 19 - (row for row in csv.reader(f) if len(row) >= 2), 20 - None, 21 - ) 19 except UnicodeDecodeError: 20 print(f"ERROR: Cannot decode file '{path}' as UTF-8") 21 sys.exit(1) 25 - finally: 26 - f.close() 22 23 + # Locate header: first row with >= 2 columns 24 + header_line = None 25 + header = None 26 + for line_num, row in enumerate(rows, start=1): 27 + if len(row) >= 2: 28 + header_line = line_num 29 + header = row 30 + break 31 + 32 if header is None: 33 print("ERROR: Missing header row") 34 sys.exit(2) ... 43 print(f"ERROR: Missing required column '{label}'") 44 sys.exit(2) 45 46 + date_idx = cols.index("date") 47 + temp_idx = cols.index("temperature") 48 + ncols = len(header) 49 + 50 + data_issues: list[tuple[int, str]] = [] 51 + valid_rows: list[tuple[date, float]] = [] 52 + 53 + for line_num, row in enumerate(rows, start=1): 54 + if line_num <= header_line: 55 + continue 56 + 57 + if len(row) < ncols: 58 + data_issues.append((line_num, "malformed row")) 59 + continue 60 + 61 + date_str = row[date_idx].strip() 62 + try: 63 + parsed_date = date.fromisoformat(date_str) 64 + except ValueError: 65 + data_issues.append((line_num, f"invalid date: {date_str}")) 66 + continue 67 + 68 + temp_str = row[temp_idx].strip() 69 + try: 70 + temp_val = float(temp_str) 71 + if not math.isfinite(temp_val): 72 + raise ValueError 73 + except ValueError: 74 + data_issues.append((line_num, f"non-numeric temperature: {temp_str}")) 75 + continue 76 + 77 + valid_rows.append((parsed_date, temp_val)) 78 + 79 print("TEMPERATURE ANOMALY REPORT") 80 + print("ASCII CHART") 81 + print("ANOMALIES") 82 + print("(none)") 83 + print("DATA ISSUES") 84 + for line_num, issue in data_issues: 85 + print(f"Line {line_num}: {issue}") 86 87 88 if __name__ == "__main__": ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ .............. [100%] 14 passed in 0.45s ⏺ All 14 tests pass. Key implementation details: - list(csv.reader(f)) reads all rows eagerly, preserving absolute line numbers via enumerate(rows, start=1) - Date validated with date.fromisoformat() — rejects impossible dates like Feb 30 - Temp validated with float() + math.isfinite() — rejects nan, inf, -inf - Rows shorter than the header column count flagged as malformed - Errors checked in order: malformed → invalid date → invalid temp; invalid rows skipped from valid_rows ✻ Brewed for 1m 34s ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add row parsing and D…) ⎿ [main d3daa7b] Add row parsing and DATA ISSUES section (prompt 7) 2 files changed, 96 insertions(+), 9 deletions(-) create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_missing_values.py ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as d3daa7b. ❯ Add ordering validation for chart-eligible rows only. Must stop immediately when detected. Must NOT sort input. TDD: 1) Create tests/test_ordering_validation.py with subprocess tests: Case A: Duplicate eligible dates: Date,Temperature 2026-01-01,70 2026-01-01,71 Expect exit 1 and stdout: ERROR: Duplicate date encountered at line 3: 2026-01-01 Case B: Out of order eligible dates: Date,Temperature 2026-01-02,70 2026-01-01,71 Expect exit 1 and stdout: ERROR: Date out of order at line 3: 2026-01-01 after 2026-01-02 Case C: Invalid rows do NOT affect ordering: Date,Temperature 2026-01-02,70 bad-date,71 (invalid date) 2026-01-03,72 Expect exit 0 (no ordering error) 2) Implement: - While reading rows, for each eligible row only: - enforce strictly increasing dates - if duplicate/out-of-order: print exact error, exit 1 immediately - Do not include invalid-date or invalid-temp rows in ordering checks Keep DATA ISSUES behavior. Human validation: - pytest -q ⎿ ⧉ Selected 36 lines from prompt_plan.md in Visual Studio Code ⏺ Write(tests/test_ordering_validation.py) ⎿ Wrote 51 lines to tests/test_ordering_validation.py 1 import subprocess 2 import sys 3 from pathlib import Path 4 5 SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 6 7 8 def run(content: str, tmp_path): 9 f = tmp_path / "data.csv" 10 f.write_text(content) … +41 lines (ctrl+o to expand) ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(temp_anomaly.py) ⎿ Added 10 lines 49 50 data_issues: list[tuple[int, str]] = [] 51 valid_rows: list[tuple[date, float]] = [] 52 + last_date: date | None = None 53 54 for line_num, row in enumerate(rows, start=1): 55 if line_num <= header_line: ... 75 data_issues.append((line_num, f"non-numeric temperature: {temp_str}")) 76 continue 77 78 + if last_date is not None: 79 + if parsed_date == last_date: 80 + print(f"ERROR: Duplicate date encountered at line {line_num}: {parsed_date}") 81 + sys.exit(1) 82 + if parsed_date < last_date: 83 + print(f"ERROR: Date out of order at line {line_num}: {parsed_date} after {last_date}") 84 + sys.exit(1) 85 + 86 + last_date = parsed_date 87 valid_rows.append((parsed_date, temp_val)) 88 89 print("TEMPERATURE ANOMALY REPORT") ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ................. [100%] 17 passed in 0.56s ⏺ All 17 tests pass. The ordering check only runs for rows that pass both date and temp validation — invalid rows are skipped via continue before the ordering logic is reached. ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add ordering validati…) ⎿ [main bdd7a23] Add ordering validation for chart-eligible rows (prompt 8) 2 files changed, 61 insertions(+) create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_ordering_validation.py ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as bdd7a23. ❯ Implement pass-1 scanning to compute min_temp and max_temp over eligible rows and build chart-scaling helpers, but still don’t print chart rows. TDD: 1) Add unit tests (not subprocess) in tests/test_chart_output.py for a pure function: - Given min_temp=10.0 max_temp=20.0: - temp=10.0 => pos 0 - temp=20.0 => pos 69 - temp=15.0 => pos round((5/10)*69)=round(34.5)=34 (Python round) - Clamp behavior at extremes - Special case min==max => pos 35 2) Implement in temp_anomaly.py: - A function like compute_pos(temp, min_temp, max_temp) -> int following spec. No change to CLI output yet besides internal plumbing. Human validation: - pytest -q ⏺ Write(tests/test_chart_output.py) ⎿ Wrote 26 lines to tests/test_chart_output.py 1 from temp_anomaly import compute_pos 2 3 4 def test_min_temp_maps_to_zero(): 5 assert compute_pos(10.0, 10.0, 20.0) == 0 6 7 8 def test_max_temp_maps_to_69(): 9 assert compute_pos(20.0, 10.0, 20.0) == 69 … +16 lines (ctrl+o to expand) ⏺ Update(temp_anomaly.py) ⎿ Added 7 lines 4 from datetime import date 5 6 7 +def compute_pos(temp: float, min_temp: float, max_temp: float) -> int: 8 + if min_temp == max_temp: 9 + return 35 10 + pos = round(((temp - min_temp) / (max_temp - min_temp)) * 69) 11 + return max(0, min(69, pos)) 12 + 13 + 14 def main() -> None: 15 if len(sys.argv) != 2: 16 print("Usage: python temp_anomaly.py ") ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ....................... [100%] 23 passed in 0.57s ⏺ All 23 tests pass. compute_pos is a pure function — the min==max guard returns 35 (center), otherwise scales linearly to [0, 69] with Python's built-in banker's rounding and clamping. ❯ commit ⎿ ⧉ Selected 38 lines from ../prompt_plan.md in Visual Studio Code ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add compute_pos chart…) ⎿ [main 46b8289] Add compute_pos chart scaling helper with unit tests (prompt 9) 2 files changed, 33 insertions(+) create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_chart_output.py ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 46b8289. ❯ Print the ASCII CHART section fully for eligible rows. For now, treat every eligible row as normal (marker '*') and anomalies will still be "(none)". TDD (subprocess golden-ish but small): 1) In tests/test_chart_output.py add a subprocess test with CSV: Date,Temperature 2026-01-01,10.0 2026-01-02,15.0 2026-01-03,20.0 Expect: - exit 0 - Output sections in order - Under ASCII CHART, three rows formatted: YYYY-MM-DD |<70 chars>| XX.XF with '*' at the computed position, '-' elsewhere. - Then the axis line exactly: |----------------------------------------------------------------------| - Then a labels line with: "10.0F" on the left and "20.0F" aligned so the max label ends under the final boundary. Keep ANOMALIES as "(none)" and DATA ISSUES empty (just the header line, no entries). 2) Implement: - Two-pass approach: - Pass 1: parse, validate ordering, collect issues, compute min/max - Print headers: TEMPERATURE ANOMALY REPORT ASCII CHART - Pass 2: parse again, validate ordering, for each eligible row: - compute pos - print chart row with '*' marker - print axis + labels line per spec - print ANOMALIES + "(none)" - print DATA ISSUES + all issues Human validation: - pytest -q - Manually run the script and confirm chart width is exactly 70 between bars. ⏺ Let me first read the current state of both files to update: ⏺ Read 2 files (ctrl+o to expand) ⏺ Now I have everything I need. Let me update the test for missing values (the 2 valid rows will now show in the chart), add the new chart subprocess test, and update the implementation: ⏺ Update(tests/test_missing_values.py) ⎿ Added 5 lines 19 EXPECTED = ( 20 "TEMPERATURE ANOMALY REPORT\n" 21 "ASCII CHART\n" 22 + # 2026-01-01,72.0 -> pos=0; 2026-01-08,73.0 -> pos=69 23 + "2026-01-01 |*---------------------------------------------------------------------| 72.0F\n" 24 + "2026-01-08 |---------------------------------------------------------------------*| 73.0F\n" 25 + "|----------------------------------------------------------------------|\n" 26 + "72.0F 73.0F\n" 27 "ANOMALIES\n" 28 "(none)\n" 29 "DATA ISSUES\n" ⏺ Now add the subprocess chart test to test_chart_output.py: ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(tests/test_chart_output.py) ⎿ Added 6 lines 1 +import subprocess 2 +import sys 3 +from pathlib import Path 4 + 5 from temp_anomaly import compute_pos 6 7 +SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 8 9 + 10 def test_min_temp_maps_to_zero(): 11 assert compute_pos(10.0, 10.0, 20.0) == 0 12 ⏺ Update(tests/test_chart_output.py) ⎿ Added 35 lines 30 31 def test_min_equals_max_returns_center(): 32 assert compute_pos(15.0, 15.0, 15.0) == 35 33 + 34 + 35 +def test_chart_three_rows(tmp_path): 36 + # pos: 10.0->0, 15.0->34 (banker's round), 20.0->69 37 + f = tmp_path / "data.csv" 38 + f.write_text( 39 + "Date,Temperature\n" 40 + "2026-01-01,10.0\n" 41 + "2026-01-02,15.0\n" 42 + "2026-01-03,20.0\n" 43 + ) 44 + result = subprocess.run( 45 + [sys.executable, str(SCRIPT), str(f)], 46 + capture_output=True, 47 + text=True, 48 + ) 49 + assert result.returncode == 0 50 + assert result.stderr == "" 51 + 52 + min_label, max_label = "10.0F", "20.0F" 53 + labels_line = min_label + " " * (72 - len(min_label) - len(max_label)) + max_label 54 + 55 + expected = ( 56 + "TEMPERATURE ANOMALY REPORT\n" 57 + "ASCII CHART\n" 58 + "2026-01-01 |*---------------------------------------------------------------------| 10.0F\n" 59 + "2026-01-02 |----------------------------------*-----------------------------------| 15.0F\n" 60 + "2026-01-03 |---------------------------------------------------------------------*| 20.0F\n" 61 + "|----------------------------------------------------------------------|\n" 62 + f"{labels_line}\n" 63 + "ANOMALIES\n" 64 + "(none)\n" 65 + "DATA ISSUES\n" 66 + ) 67 + assert result.stdout == expected ⏺ Now update temp_anomaly.py to print the chart: ⏺ Update(temp_anomaly.py) ⎿ Added 13 lines 95 96 print("TEMPERATURE ANOMALY REPORT") 97 print("ASCII CHART") 98 + 99 + if valid_rows: 100 + min_temp = min(t for _, t in valid_rows) 101 + max_temp = max(t for _, t in valid_rows) 102 + for d, temp in valid_rows: 103 + pos = compute_pos(temp, min_temp, max_temp) 104 + bar = "-" * pos + "*" + "-" * (69 - pos) 105 + print(f"{d} |{bar}| {temp:.1f}F") 106 + min_label = f"{min_temp:.1f}F" 107 + max_label = f"{max_temp:.1f}F" 108 + print("|" + "-" * 70 + "|") 109 + print(min_label + " " * (72 - len(min_label) - len(max_label)) + max_label) 110 + 111 print("ANOMALIES") 112 print("(none)") 113 print("DATA ISSUES") ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ........................ [100%] 24 passed in 0.58s ⏺ All 24 tests pass. Let me do the manual visual check: ⏺ Bash(printf "Date,Temperature\n2026-01-01,10.0\n2026-01-02,15.0\n2026-01-03,20.0\n" | python3 temp_anomaly.py /dev/stdin 2>&1) ⎿ TEMPERATURE ANOMALY REPORT ASCII CHART 2026-01-01 |*---------------------------------------------------------------------| 10.0F … +7 lines (ctrl+o to expand) ⏺ Chart width is exactly 70 chars between the | bars, axis and labels align correctly. ✻ Baked for 1m 59s ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Print ASCII CHART sec…) ⎿ [main 1f7acae] Print ASCII CHART section with scaled bar rows and axis (prompt 10) 3 files changed, 59 insertions(+) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 1f7acae. ❯ Implement rolling window and anomaly detection logic; record anomalies, but keep chart markers as '*' for now. TDD: 1) Add tests/test_anomaly_detection.py with unit tests for: - rolling window excludes current row - requires >=10 priors - window max size 30 (use a sequence and verify size) - stddev uses sample ddof=1 (compare to statistics.stdev) - strict inequality: abs(diff) > 2*stddev (not >=) - stddev==0 => skip detection 2) Implement: - Maintain a list of prior temps (eligible only), pop oldest when >30 - For each eligible row: - if priors < 10: no detection - else mean = sum(priors)/len(priors) - stddev = statistics.stdev(priors) (sample) - if stddev==0: skip - if anomaly: store an Anomaly record with date,temp,mean,diff,z - Append current temp to window after processing No output changes required yet beyond internal anomaly list accumulation. Human validation: - pytest -q ⏺ Write(tests/test_anomaly_detection.py) ⎿ Wrote 57 lines to tests/test_anomaly_detection.py 1 import statistics 2 3 from temp_anomaly import check_anomaly, update_window 4 5 6 def test_fewer_than_10_priors_returns_none(): 7 assert check_anomaly(999.0, [1.0] * 9) is None 8 9 10 def test_exactly_10_priors_enables_detection(): … +47 lines (ctrl+o to expand) ⏺ Now add the dataclass, check_anomaly, update_window, and wire them into main: ⏺ Update(temp_anomaly.py) ⎿ Added 2 lines 1 import csv 2 import math 3 +import statistics 4 import sys 5 +from dataclasses import dataclass 6 from datetime import date 7 8 ⏺ Update(temp_anomaly.py) ⎿ Added 29 lines 6 from datetime import date 7 8 9 +@dataclass 10 +class Anomaly: 11 + date: date 12 + temp: float 13 + mean: float 14 + diff: float 15 + z: float 16 + 17 + 18 +def check_anomaly(temp: float, window: list[float]) -> tuple[float, float, float] | None: 19 + """Return (mean, diff, z) if temp is anomalous vs window, else None.""" 20 + if len(window) < 10: 21 + return None 22 + m = sum(window) / len(window) 23 + sd = statistics.stdev(window) 24 + if sd == 0.0: 25 + return None 26 + diff = temp - m 27 + if abs(diff) > 2 * sd: 28 + return (m, diff, diff / sd) 29 + return None 30 + 31 + 32 +def update_window(window: list[float], temp: float) -> None: 33 + window.append(temp) 34 + if len(window) > 30: 35 + window.pop(0) 36 + 37 + 38 def compute_pos(temp: float, min_temp: float, max_temp: float) -> int: 39 if min_temp == max_temp: 40 return 35 ⏺ Now wire anomaly detection into main after valid_rows is built: ⏺ Update(temp_anomaly.py) ⎿ Added 9 lines 124 last_date = parsed_date 125 valid_rows.append((parsed_date, temp_val)) 126 127 + anomalies: list[Anomaly] = [] 128 + window: list[float] = [] 129 + for d, temp in valid_rows: 130 + result = check_anomaly(temp, window) 131 + if result is not None: 132 + m, diff, z = result 133 + anomalies.append(Anomaly(d, temp, m, diff, z)) 134 + update_window(window, temp) 135 + 136 print("TEMPERATURE ANOMALY REPORT") 137 print("ASCII CHART") 138 ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ Error: Exit code 1 .....F.......................... [100%] =================================== FAILURES =================================== ______________ test_strict_inequality_at_boundary_is_not_anomaly _______________ def test_strict_inequality_at_boundary_is_not_anomaly(): window = list(range(1, 11)) m = statistics.mean(window) sd = statistics.stdev(window) temp_at_boundary = m + 2 * sd # exactly at threshold: NOT anomaly (strict >) … +26 lines (ctrl+o to see all) ⏺ Floating-point issue: m + 2*sd - m isn't exactly 2*sd, so the z-score computes as 2.000...04. Fix the boundary test to use a value clearly below the threshold: ⏺ Update(tests/test_anomaly_detection.py) ⎿ Added 3 lines, removed 3 lines 38 assert abs(z - diff / expected_sd) < 1e-10 39 40 41 -def test_strict_inequality_at_boundary_is_not_anomaly(): 41 +def test_strict_inequality_just_below_boundary_is_not_anomaly(): 42 window = list(range(1, 11)) 43 m = statistics.mean(window) 44 sd = statistics.stdev(window) 45 - temp_at_boundary = m + 2 * sd # exactly at threshold: NOT anomaly (strict >) 46 - assert check_anomaly(temp_at_boundary, window) is None 45 + # Slightly below 2*sd: strict > means this is NOT an anomaly 46 + assert check_anomaly(m + 2 * sd - 0.001, window) is None 47 48 49 def test_strict_inequality_just_above_boundary_is_anomaly(): ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ................................ [100%] 32 passed in 0.77s ⏺ All 32 tests pass. One note: the exact-boundary test (m + 2*sd) fails due to floating-point — diff = temp - m doesn't equal exactly 2*sd because floating-point subtraction isn't lossless. The test uses m + 2*sd - 0.001 instead, which clearly tests the strict > semantics without the precision issue. ✻ Cooked for 1m 45s ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add rolling window an…) ⎿ [main cbb90c2] Add rolling window anomaly detection logic (prompt 11) 2 files changed, 97 insertions(+) create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_anomaly_detection.py ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as cbb90c2. ❯ Change chart markers: - '#' if the row is an anomaly - '*' otherwise TDD: 1) Add a subprocess test (tests/test_chart_output.py or a new file) with a constructed dataset that guarantees at least one anomaly after >=10 priors. Example idea: - 10 days at temp 50.0 - day 11 at temp 100.0 (stddev==0 for priors, so anomaly detection skipped!) So instead create priors with small variance, e.g. temps 50..59 (10 values), then an extreme 100. Verify: - Exit 0 - Chart line for anomaly date contains '#' at correct position. 2) Implement: - During pass 2, after you compute anomaly status for the current row, use '#' marker if anomaly else '*'. - Still print anomalies table as "(none)" for now (next prompt will format it). Human validation: - pytest -q - Manually inspect the output to see '#' on anomaly row. ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(temp_anomaly.py) ⎿ Added 3 lines, removed 1 line 139 if valid_rows: 140 min_temp = min(t for _, t in valid_rows) 141 max_temp = max(t for _, t in valid_rows) 142 + anomaly_dates = {a.date for a in anomalies} 143 for d, temp in valid_rows: 144 pos = compute_pos(temp, min_temp, max_temp) 144 - bar = "-" * pos + "*" + "-" * (69 - pos) 145 + marker = "#" if d in anomaly_dates else "*" 146 + bar = "-" * pos + marker + "-" * (69 - pos) 147 print(f"{d} |{bar}| {temp:.1f}F") 148 min_label = f"{min_temp:.1f}F" 149 max_label = f"{max_temp:.1f}F" ⏺ Now add the subprocess test. 10 priors with variance (50–59), then an extreme at 100: ⏺ Update(tests/test_chart_output.py) ⎿ Added 21 lines 32 assert compute_pos(15.0, 15.0, 15.0) == 35 33 34 35 +def test_anomaly_row_uses_hash_marker(tmp_path): 36 + # Priors: 2026-01-01..10 at temps 50-59 (mean=54.5, stdev≈3.03) 37 + # Day 11 at 100.0: diff=45.5 >> 2*3.03 → anomaly → '#' marker 38 + lines = ["Date,Temperature"] 39 + for i in range(10): 40 + lines.append(f"2026-01-{i+1:02d},{50+i}.0") 41 + lines.append("2026-01-11,100.0") 42 + f = tmp_path / "data.csv" 43 + f.write_text("\n".join(lines) + "\n") 44 + result = subprocess.run( 45 + [sys.executable, str(SCRIPT), str(f)], 46 + capture_output=True, 47 + text=True, 48 + ) 49 + assert result.returncode == 0 50 + assert result.stderr == "" 51 + # Day 11 (anomaly) -> '#' at pos 69 (max); day 01 (normal) -> '*' at pos 0 52 + assert "2026-01-11 |---------------------------------------------------------------------#| 100.0F" in result.stdout 53 + assert "2026-01-01 |*" in result.stdout 54 + 55 + 56 def test_chart_three_rows(tmp_path): 57 # pos: 10.0->0, 15.0->34 (banker's round), 20.0->69 58 f = tmp_path / "data.csv" ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ................................. [100%] 33 passed in 0.78s ⏺ All 33 tests pass. Let me do the manual check too: ⏺ Bash(python3 -c " lines = ['Date,Temperature']…) ⎿ TEMPERATURE ANOMALY REPORT ASCII CHART 2026-01-01 |*---------------------------------------------------------------------| 50.0F … +12 lines (ctrl+o to expand) ⏺ # appears on the anomaly row (day 11), * on all normal rows. ✻ Crunched for 46s ❯ commit ⎿ ⧉ Selected 24 lines from ../prompt_plan.md in Visual Studio Code ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Use '#' marker for an…) ⎿ [main de3a96f] Use '#' marker for anomaly rows in ASCII chart (prompt 12) 2 files changed, 24 insertions(+), 1 deletion(-) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as de3a96f. ❯ Implement the ANOMALIES section table rendering. TDD: 1) In tests/test_anomaly_detection.py add a subprocess test with a dataset that produces exactly one anomaly. Assert: - The ANOMALIES section includes header row: Date Temp(F) Mean(F) Diff(F) Z-Score (Spacing can be flexible ONLY if you choose fixed-width; but the numeric formats must match exactly.) - The anomaly line contains: - Temp/Mean/Diff to 1 decimal - Diff with explicit sign (+/-) - Z-Score with explicit sign (+/-) and 1 decimal - Chronological order (they will be encountered in order) 2) Keep "(none)" exactly when there are no anomalies. Implementation: - Store anomalies during pass2, then after chart+axis print: ANOMALIES Human validation: - pytest -q - Run on a sample file and confirm numeric formats. ⏺ First let me check the current test files to understand what to add: ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(tests/test_anomaly_detection.py) ⎿ Added 5 lines 1 import statistics 2 +import subprocess 3 +import sys 4 +from pathlib import Path 5 6 from temp_anomaly import check_anomaly, update_window 7 8 +SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 9 10 + 11 def test_fewer_than_10_priors_returns_none(): 12 assert check_anomaly(999.0, [1.0] * 9) is None 13 ⏺ Update(tests/test_anomaly_detection.py) ⎿ Added 48 lines 60 61 def test_stddev_zero_skips_detection(): 62 assert check_anomaly(999.0, [5.0] * 10) is None 63 + 64 + 65 +def test_anomalies_table_format(tmp_path): 66 + # 10 priors 50-59, then extreme 100.0 -> exactly one anomaly 67 + lines = ["Date,Temperature"] 68 + for i in range(10): 69 + lines.append(f"2026-01-{i+1:02d},{50+i}.0") 70 + lines.append("2026-01-11,100.0") 71 + f = tmp_path / "data.csv" 72 + f.write_text("\n".join(lines) + "\n") 73 + result = subprocess.run( 74 + [sys.executable, str(SCRIPT), str(f)], 75 + capture_output=True, 76 + text=True, 77 + ) 78 + assert result.returncode == 0 79 + assert result.stderr == "" 80 + 81 + # Compute expected values 82 + window = list(range(50, 60)) 83 + m = statistics.mean(window) # 54.5 84 + sd = statistics.stdev(window) 85 + diff = 100.0 - m # +45.5 86 + z = diff / sd # ~+15.0 87 + 88 + expected_header = ( 89 + f"{'Date':<10} {'Temp(F)':>7} {'Mean(F)':>7} {'Diff(F)':>7} {'Z-Score':>7}" 90 + ) 91 + expected_row = ( 92 + f"{'2026-01-11':<10} {100.0:>7.1f} {m:>7.1f} {diff:>+7.1f} {z:>+7.1f}" 93 + ) 94 + 95 + assert "ANOMALIES\n" in result.stdout 96 + assert expected_header in result.stdout 97 + assert expected_row in result.stdout 98 + 99 + 100 +def test_anomalies_none_when_no_anomalies(tmp_path): 101 + # Only 3 rows -> no window for detection -> "(none)" 102 + f = tmp_path / "data.csv" 103 + f.write_text("Date,Temperature\n2026-01-01,50.0\n2026-01-02,51.0\n2026-01-03,52.0\n") 104 + result = subprocess.run( 105 + [sys.executable, str(SCRIPT), str(f)], 106 + capture_output=True, 107 + text=True, 108 + ) 109 + assert result.returncode == 0 110 + assert "ANOMALIES\n(none)\n" in result.stdout ⏺ Now implement the table rendering in temp_anomaly.py: ⏺ Update(temp_anomaly.py) ⎿ Added 6 lines, removed 1 line 151 print(min_label + " " * (72 - len(min_label) - len(max_label)) + max_label) 152 153 print("ANOMALIES") 154 - print("(none)") 154 + if not anomalies: 155 + print("(none)") 156 + else: 157 + print(f"{'Date':<10} {'Temp(F)':>7} {'Mean(F)':>7} {'Diff(F)':>7} {'Z-Score':>7}") 158 + for a in anomalies: 159 + print(f"{a.date!s:<10} {a.temp:>7.1f} {a.mean:>7.1f} {a.diff:>+7.1f} {a.z:>+7.1f}") 160 print("DATA ISSUES") 161 for line_num, issue in data_issues: 162 print(f"Line {line_num}: {issue}") ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q 2>&1) ⎿ ................................... [100%] 35 passed in 0.86s ⏺ All 35 tests pass. Let me do a quick visual check: ⏺ Bash(python3 -c " lines = ['Date,Temperature']…) ⎿ |----------------------------------------------------------------------| 50.0F 100.0F ANOMALIES … +3 lines (ctrl+o to expand) ⏺ Clean table with signed Diff and Z-Score, both to 1 decimal, chronological order preserved. ✻ Brewed for 1m 28s ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Implement ANOMALIES t…) ⎿ [main 3c51760] Implement ANOMALIES table rendering (prompt 13) 2 files changed, 59 insertions(+), 1 deletion(-) ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 3c51760. ❯ Add at least one full golden test per spec. TDD: 1) Create tests/test_golden_output.py that: - Writes a CSV fixture including: - valid eligible rows (enough to create anomalies) - malformed row - invalid date row - non-numeric temp row - NaN/inf temp rows - Runs subprocess: python temp_anomaly.py - Asserts: - returncode == 0 - stderr == "" - stdout == expected_output (exact match) 2) In the expected_output string, ensure the four sections appear in exact order with exact formatting. Implementation adjustments: - Fix any minor formatting drift uncovered by the golden test: - chart width 70 - axis and labels alignment (max label ends under final boundary) - deterministic rounding via Python round() and format to 1 decimal - DATA ISSUES in ascending line order with line numbers including header as line 1 Human validation: - pytest -q - Re-run the golden test twice to ensure identical stdout both times. ⎿ ⧉ Selected 28 lines from prompt_plan.md in Visual Studio Code ⏺ Let me first run the program manually with a test fixture to see the exact current output, then write the golden test: ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -c " fixture = '''Date,Temperature,Notes…) ⎿ /var/folders/f0/69wncpqd02s3j1r_z5sfddd00000gq/T/tmpf141sj3n.csv ⏺ Bash(python3 temp_anomaly.py /var/folders/f0/69wncpqd02s3j1r_z5sfddd00000gq/T/tmpf141sj3n.csv | cat -A | head -30) ⎿ cat: illegal option -- A usage: cat [-belnstuv] [file ...] Exception ignored in: <_io.TextIOWrapper name='' mode='w' encoding='utf-8'> BrokenPipeError: [Errno 32] Broken pipe ⏺ Bash(python3 temp_anomaly.py /var/folders/f0/69wncpqd02s3j1r_z5sfddd00000gq/T/tmpf141sj3n.csv) ⎿ TEMPERATURE ANOMALY REPORT ASCII CHART 2026-01-01 |*---------------------------------------------------------------------| 50.0F … +22 lines (ctrl+o to expand) ⏺ Output looks perfect. Now I'll write the golden test with the expected string built programmatically (independent from the implementation): ⏺ Write(tests/test_golden_output.py) ⎿ Wrote 127 lines to tests/test_golden_output.py 1 """Full golden test: exact stdout match for a fixture covering all features.""" 2 import statistics 3 import subprocess 4 import sys 5 from datetime import date 6 from pathlib import Path 7 8 SCRIPT = Path(__file__).parent.parent / "temp_anomaly.py" 9 10 FIXTURE = """\ … +117 lines (ctrl+o to expand) ⏺ Bash(python3 -m pytest -q 2>&1) ⎿ .................................... [100%] 36 passed in 0.90s ⏺ Bash(python3 -m pytest tests/test_golden_output.py -v 2>&1 && python3 -m pytest tests/test_golden_output.py -v 2>&1) ⎿ ============================= test session starts ============================== platform darwin -- Python 3.11.9, pytest-9.0.2, pluggy-1.6.0 -- /Library/Frameworks/Python.framework/Versions/3.11/bin/python3 cachedir: .pytest_cache … +15 lines (ctrl+o to expand) ⏺ All 36 tests pass, golden test is deterministic across runs. The fixture covers all feature paths (10 valid baseline rows, 1 anomaly, malformed row, invalid date, non-numeric temp, NaN, inf), and _build_expected() independently recomputes the expected output using the same mathematics without duplicating the implementation code. ✻ Brewed for 2m 29s ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add full golden outpu…) ⎿ [main 8386395] Add full golden output test covering all features (prompt 14) 1 file changed, 127 insertions(+) create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_golden_output.py ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 8386395. ❯ Finalize README.md and AGENTS.md exactly per spec. TDD-ish: 1) Add a simple test (optional) that checks README.md and AGENTS.md exist; keep it lightweight. 2) Update AGENTS.md to specify: - black formatting - ruff linting - mypy type checking - pytest + pytest-cov - coverage >= 90% - pre-commit hooks required - rules: public functions have docstrings; no stack traces for user errors; error messages match spec exactly 3) Update README.md with: - overview - Python 3.12+ requirement - venv named venv - install instructions - usage example - required CSV schema - example input - example output - running tests Human validation: - Open README.md and verify it contains every required bullet. - Run: pytest -q --cov --cov-fail-under=90 - Run: ruff check . ; black --check . ; mypy . ⎿ ⧉ Selected 27 lines from prompt_plan.md in Visual Studio Code ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly && python3 -m pytest -q --cov=temp_anomaly --cov-fail-under=90 2>…) ⎿ ERROR: usage: __main__.py [options] [file_or_dir] [file_or_dir] [...] __main__.py: error: unrecognized arguments: --cov=temp_anomaly --cov-fail-under=90 inifile: None rootdir: /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly ⏺ Bash(pip3 install pytest-cov --quiet && python3 -m pytest -q --cov=temp_anomaly --cov-fail-under=90 2>&1 | tail -15) ⎿ Interrupted · What should Claude do instead? ❯ We need to be using a virtual environment. Call it venv. Use python3.14 -m venv venv to create it ⏺ Bash(python3.14 -m venv venv) ⎿ (No output) ⏺ Bash(venv/bin/pip install -q -r requirements.txt && venv/bin/python -m pytest -q 2>&1) ⎿ [notice] A new release of pip is available: 26.0 -> 26.0.1 [notice] To update, run: /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough/temp-anomaly/venv/bin/python3.14 -m pip install --upgrade pip .................................... [100%] 36 passed in 1.16s ⏺ All 36 tests pass in the venv. Now I'll proceed with the README/AGENTS work using venv/bin/python and venv/bin/pytest. ⏺ Bash(venv/bin/python -m pytest -q --cov=temp_anomaly --cov-fail-under=90 2>&1 | tail -15) ⎿ .................................... ERROR: Coverage failure: total of 23 is less than fail-under=90 [100%] … +10 lines (ctrl+o to expand) ⏺ The 23% coverage is because subprocess tests run in separate processes — pytest-cov can't see that code. I need to enable subprocess coverage. Let me set that up: ⏺ Bash(venv/bin/python -c "import site; print(site.getsitepackages())") ⎿ Interrupted · What should Claude do instead? ❯ Are you sure you are trying to run the test coverage properly? coverage run -m pytest coverage report -m ⏺ Bash(venv/bin/coverage run -m pytest -q && venv/bin/coverage report -m 2>&1) ⎿ .................................... [100%] 36 passed in 1.01s Name Stmts Miss Cover Missing … +12 lines (ctrl+o to expand) ⏺ The issue is that main() (lines 46-162) only runs in subprocesses, so coverage can't track it. I need to enable subprocess coverage. Let me set it up: ⏺ Bash(venv/bin/python -c "import site; print(site.getsitepackages()[0])") ⎿ Interrupted · What should Claude do instead? ❯ I don't see the subprocess ⏺ The 23% on temp_anomaly.py is the core issue. Let me show exactly why: ⏺ Bash(venv/bin/coverage run -m pytest -q && venv/bin/coverage report -m --include=temp_anomaly.py 2>&1) ⎿ .................................... [100%] 36 passed in 0.99s Name Stmts Miss Cover Missing … +4 lines (ctrl+o to expand) ⏺ Read 1 file (ctrl+o to expand) ⏺ Lines 46–162 are all of main(). Every test calls it via subprocess.run([sys.executable, str(SCRIPT), ...]) — that spawns a new Python process, so the coverage tracker running in the pytest process never sees those lines execute. The unit tests (lines 1–44: compute_pos, check_anomaly, update_window) are imported directly and counted, hence 30/130 = 23%. To reach 90% we have two options: 1. Configure subprocess coverage — add a .coveragerc with subprocess = true and a sitecustomize.py in the venv so child processes also report coverage back 2. Add direct main() tests — use monkeypatch/sys.argv to call main() in-process with pytest.raises(SystemExit), bypassing subprocess entirely Which approach would you prefer? ✻ Cogitated for 34s ❯ 2 ⏺ Read 1 file (ctrl+o to expand) ⏺ Write(tests/test_main_direct.py) ⎿ User rejected update to tests/test_main_direct.py 1 -"""Direct in-process tests for main() via dependency-injected argv.""" 1 +"""Direct in-process tests for main() to achieve coverage of lines run via subprocess.""" 2 import pytest 3 from temp_anomaly import main 4 5 6 -def _run(capsys, argv: list[str]): 6 +def _run(monkeypatch, capsys, argv: list[str]): 7 + monkeypatch.setattr("sys.argv", argv) 8 with pytest.raises(SystemExit) as exc: 8 - main(argv) 9 + main() 10 return exc.value.code, capsys.readouterr() 11 12 13 # --- usage / arg count --- 14 14 -def test_no_args_usage(capsys): 15 - code, out = _run(capsys, ["prog"]) 15 +def test_no_args_usage(monkeypatch, capsys): 16 + code, out = _run(monkeypatch, capsys, ["prog"]) 17 assert code == 1 18 assert out.out == "Usage: python temp_anomaly.py \n" 19 assert out.err == "" 20 21 21 -def test_too_many_args_usage(capsys): 22 - code, out = _run(capsys, ["prog", "a.csv", "b.csv"]) 22 +def test_too_many_args_usage(monkeypatch, capsys): 23 + code, out = _run(monkeypatch, capsys, ["prog", "a.csv", "b.csv"]) 24 assert code == 1 25 assert out.out == "Usage: python temp_anomaly.py \n" 26 27 28 # --- file errors --- 29 29 -def test_missing_file_error(capsys): 30 - code, out = _run(capsys, ["prog", "no_such_file.csv"]) 30 +def test_missing_file_error(monkeypatch, capsys): 31 + code, out = _run(monkeypatch, capsys, ["prog", "no_such_file.csv"]) 32 assert code == 1 33 assert out.out == "ERROR: Cannot open file 'no_such_file.csv'\n" 34 35 35 -def test_invalid_utf8_error(capsys, tmp_path): 36 +def test_invalid_utf8_error(monkeypatch, capsys, tmp_path): 37 f = tmp_path / "bad.csv" 38 f.write_bytes(b"\xff\xfe\xff") 38 - code, out = _run(capsys, ["prog", str(f)]) 39 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 40 assert code == 1 41 assert out.out == f"ERROR: Cannot decode file '{f}' as UTF-8\n" 42 43 44 # --- schema errors --- 45 45 -def test_missing_header(capsys, tmp_path): 46 +def test_missing_header(monkeypatch, capsys, tmp_path): 47 f = tmp_path / "d.csv" 48 f.write_text("only_one_column\n") 48 - code, out = _run(capsys, ["prog", str(f)]) 49 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 50 assert code == 2 51 assert out.out == "ERROR: Missing header row\n" 52 53 53 -def test_duplicate_date_column(capsys, tmp_path): 54 +def test_duplicate_date_column(monkeypatch, capsys, tmp_path): 55 f = tmp_path / "d.csv" 56 f.write_text("Date,DATE,Temperature\n") 56 - code, out = _run(capsys, ["prog", str(f)]) 57 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 58 assert code == 2 59 assert out.out == "ERROR: Duplicate column 'Date'\n" 60 61 61 -def test_missing_temperature_column(capsys, tmp_path): 62 +def test_missing_temperature_column(monkeypatch, capsys, tmp_path): 63 f = tmp_path / "d.csv" 64 f.write_text("Date,Other\n") 64 - code, out = _run(capsys, ["prog", str(f)]) 65 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 66 assert code == 2 67 assert out.out == "ERROR: Missing required column 'Temperature'\n" 68 69 70 # --- ordering errors --- 71 71 -def test_duplicate_date_ordering(capsys, tmp_path): 72 +def test_duplicate_date_ordering(monkeypatch, capsys, tmp_path): 73 f = tmp_path / "d.csv" 74 f.write_text("Date,Temperature\n2026-01-01,70\n2026-01-01,71\n") 74 - code, out = _run(capsys, ["prog", str(f)]) 75 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 76 assert code == 1 77 assert out.out == "ERROR: Duplicate date encountered at line 3: 2026-01-01\n" 78 79 79 -def test_out_of_order_date(capsys, tmp_path): 80 +def test_out_of_order_date(monkeypatch, capsys, tmp_path): 81 f = tmp_path / "d.csv" 82 f.write_text("Date,Temperature\n2026-01-02,70\n2026-01-01,71\n") 82 - code, out = _run(capsys, ["prog", str(f)]) 83 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 84 assert code == 1 85 assert out.out == "ERROR: Date out of order at line 3: 2026-01-01 after 2026-01-02\n" 86 87 88 # --- successful output paths --- 89 89 -def test_valid_no_data_issues(capsys, tmp_path): 90 +def test_valid_no_data_issues(monkeypatch, capsys, tmp_path): 91 f = tmp_path / "d.csv" 92 f.write_text("Date,Temperature\n2026-01-01,50.0\n2026-01-02,51.0\n") 92 - main(["prog", str(f)]) 93 - out = capsys.readouterr() 93 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 94 + assert code == 0 95 assert out.out.startswith("TEMPERATURE ANOMALY REPORT\n") 96 assert "ANOMALIES\n(none)\n" in out.out 97 assert "DATA ISSUES\n" in out.out 98 assert out.err == "" 99 100 100 -def test_valid_with_data_issues(capsys, tmp_path): 101 +def test_valid_with_data_issues(monkeypatch, capsys, tmp_path): 102 f = tmp_path / "d.csv" 103 f.write_text( 104 "Date,Temperature\n" 105 "2026-01-01,50.0\n" 105 - "bad-date,70\n" 106 - "2026-01-02,nan\n" 106 + "bad-date,70\n" # invalid date -> data issue 107 + "2026-01-02,nan\n" # non-numeric -> data issue 108 "2026-01-03,51.0\n" 109 ) 109 - main(["prog", str(f)]) 110 - out = capsys.readouterr() 110 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 111 + assert code == 0 112 assert "Line 3: invalid date: bad-date\n" in out.out 113 assert "Line 4: non-numeric temperature: nan\n" in out.out 114 115 115 -def test_valid_with_anomaly_and_hash_marker(capsys, tmp_path): 116 +def test_valid_with_anomaly_and_hash_marker(monkeypatch, capsys, tmp_path): 117 lines = ["Date,Temperature"] 118 for i in range(10): 119 lines.append(f"2026-01-{i+1:02d},{50+i}.0") 120 lines.append("2026-01-11,100.0") 121 f = tmp_path / "d.csv" 122 f.write_text("\n".join(lines) + "\n") 122 - main(["prog", str(f)]) 123 - out = capsys.readouterr() 124 - assert "#" in out.out 125 - assert "2026-01-11" in out.out 126 - assert "(none)" not in out.out 123 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 124 + assert code == 0 125 + assert "#" in out.out # anomaly marker in chart 126 + assert "2026-01-11" in out.out # anomaly in table 127 + assert "(none)" not in out.out # anomalies section has content 128 129 129 -def test_malformed_row_in_data_issues(capsys, tmp_path): 130 +def test_min_equals_max_uses_center(monkeypatch, capsys, tmp_path): 131 + # Single row: min==max -> compute_pos returns 35 132 f = tmp_path / "d.csv" 131 - # Row with fewer columns than header -> malformed 132 - f.write_text("Date,Temperature\n2026-01-01\n2026-01-02,51.0\n") 133 - main(["prog", str(f)]) 134 - out = capsys.readouterr() 135 - assert "Line 2: malformed row\n" in out.out 136 - 137 - 138 -def test_argv_none_uses_sys_argv(monkeypatch, capsys): 139 - # Exercises the argv=None -> sys.argv branch 140 - monkeypatch.setattr("sys.argv", ["prog"]) 141 - with pytest.raises(SystemExit) as exc: 142 - main() # called with no argument 143 - assert exc.value.code == 1 144 - 145 - 146 -def test_min_equals_max_uses_center(capsys, tmp_path): 147 - f = tmp_path / "d.csv" 133 f.write_text("Date,Temperature\n2026-01-01,50.0\n") 149 - main(["prog", str(f)]) 150 - out = capsys.readouterr() 134 + code, out = _run(monkeypatch, capsys, ["prog", str(f)]) 135 + assert code == 0 136 + # pos=35: 35 dashes, *, 34 dashes 137 assert "|" + "-" * 35 + "*" + "-" * 34 + "|" in out.out ❯ this approach is crazy. Let's update main to take argv as a parameter rather than just using sys.argv. This will make it much easier to test - dependency injection ⏺ Good call. I'll update main() to accept argv as a parameter with sys.argv as the default: ⏺ Read 1 file (ctrl+o to expand) ⏺ Update(temp_anomaly.py) ⎿ Added 5 lines, removed 3 lines 42 return max(0, min(69, pos)) 43 44 45 -def main() -> None: 46 - if len(sys.argv) != 2: 45 +def main(argv: list[str] | None = None) -> None: 46 + if argv is None: 47 + argv = sys.argv 48 + if len(argv) != 2: 49 print("Usage: python temp_anomaly.py ") 50 sys.exit(1) 51 50 - path = sys.argv[1] 52 + path = argv[1] 53 try: 54 with open(path, encoding="utf-8-sig", newline="") as f: 55 rows = list(csv.reader(f)) ⏺ Now write the direct in-process test file: ⏺ Write(tests/test_main_direct.py) ⎿ Wrote 134 lines to tests/test_main_direct.py 1 """Direct in-process tests for main() via dependency-injected argv.""" 2 import pytest 3 from temp_anomaly import main 4 5 6 def _run(capsys, argv: list[str]): 7 with pytest.raises(SystemExit) as exc: 8 main(argv) 9 return exc.value.code, capsys.readouterr() … +124 lines (ctrl+o to expand) ⏺ Bash(venv/bin/coverage run -m pytest -q && venv/bin/coverage report -m --include=temp_anomaly.py 2>&1) ⎿ ................................................. [100%] 49 passed in 1.02s Name Stmts Miss Cover Missing … +4 lines (ctrl+o to expand) ⏺ 97% coverage on temp_anomaly.py. Let me check the 4 missed lines: ⏺ Read 1 file (ctrl+o to expand) ⏺ - Line 47: argv = sys.argv — the None default path (never called without args in tests) - Lines 99–100: malformed row path in main() — tested via subprocess but not directly - Line 168: main() call from __main__ block Let me add two quick direct tests to cover malformed rows and the argv=None default: ⏺ Update(tests/test_main_direct.py) ⎿ Added 17 lines 126 assert "(none)" not in out.out 127 128 129 +def test_malformed_row_in_data_issues(capsys, tmp_path): 130 + f = tmp_path / "d.csv" 131 + # Row with fewer columns than header -> malformed 132 + f.write_text("Date,Temperature\n2026-01-01\n2026-01-02,51.0\n") 133 + main(["prog", str(f)]) 134 + out = capsys.readouterr() 135 + assert "Line 2: malformed row\n" in out.out 136 + 137 + 138 +def test_argv_none_uses_sys_argv(monkeypatch, capsys): 139 + # Exercises the argv=None -> sys.argv branch 140 + monkeypatch.setattr("sys.argv", ["prog"]) 141 + with pytest.raises(SystemExit) as exc: 142 + main() # called with no argument 143 + assert exc.value.code == 1 144 + 145 + 146 def test_min_equals_max_uses_center(capsys, tmp_path): 147 f = tmp_path / "d.csv" 148 f.write_text("Date,Temperature\n2026-01-01,50.0\n") ⏺ Bash(venv/bin/coverage run -m pytest -q && venv/bin/coverage report -m --include=temp_anomaly.py 2>&1) ⎿ ................................................... [100%] 51 passed in 0.99s Name Stmts Miss Cover Missing … +4 lines (ctrl+o to expand) ⏺ 99% — only line 168 (main() inside if __name__ == "__main__") is uncovered, which is expected since we never execute the script as __main__ directly in tests. 51 tests all passing. ✻ Cooked for 1m 1s ❯ you haven't updated the README or AGENTS ⎿ ⧉ Selected 27 lines from ../prompt_plan.md in Visual Studio Code ⏺ Write(README.md) ⎿ Added 71 lines, removed 1 line 1 # temp-anomaly 2 3 -Placeholder — to be expanded. 3 +Reads a CSV file of daily temperature readings, detects statistical anomalies using a 30-day rolling window, and prints a fixed-width ASCII chart with an anomaly report. 4 + 5 +## Requirements 6 + 7 +- Python 3.12+ 8 + 9 +## Setup 10 + 11 +```bash 12 +python3 -m venv venv 13 +source venv/bin/activate 14 +pip install -r requirements.txt 15 +``` 16 + 17 +## Usage 18 + 19 +```bash 20 +python temp_anomaly.py 21 +``` 22 + 23 +### Exit codes 24 + 25 +| Code | Meaning | 26 +|------|---------| 27 +| 0 | Success | 28 +| 1 | Usage error, file error, or ordering error | 29 +| 2 | Schema error | 30 + 31 +## CSV Schema 32 + 33 +The input file must be UTF-8 (optional BOM) with at least these two columns (case-insensitive, extra columns allowed): 34 + 35 +| Column | Format | Notes | 36 +|--------|--------|-------| 37 +| `Date` | `YYYY-MM-DD` | Must be strictly increasing | 38 +| `Temperature` | Decimal number | Must be finite (no NaN/Inf) | 39 + 40 +## Example Input 41 + 42 +```csv 43 +Date,Temperature 44 +2026-01-01,50.0 45 +2026-01-02,51.0 46 +2026-01-03,49.5 47 +``` 48 + 49 +## Example Output 50 + 51 +``` 52 +TEMPERATURE ANOMALY REPORT 53 +ASCII CHART 54 +2026-01-01 |*---------------------------------------------------------------------| 50.0F 55 +2026-01-02 |---------------------------------------------------------------------*| 51.0F 56 +2026-01-03 |----------------------------------*-----------------------------------| 49.5F 57 +|----------------------------------------------------------------------| 58 +49.5F 51.0F 59 +ANOMALIES 60 +(none) 61 +DATA ISSUES 62 +``` 63 + 64 +## Running Tests 65 + 66 +```bash 67 +# Run all tests 68 +venv/bin/python -m pytest -q 69 + 70 +# Run with coverage 71 +venv/bin/coverage run -m pytest 72 +venv/bin/coverage report -m 73 +``` ⏺ Write(AGENTS.md) ⎿ Added 36 lines, removed 1 line 1 # AGENTS 2 3 -Placeholder — to be expanded. 3 +Guidelines for AI agents and contributors working on this project. 4 + 5 +## Toolchain 6 + 7 +| Tool | Purpose | Command | 8 +|------|---------|---------| 9 +| `black` | Code formatting | `black .` | 10 +| `ruff` | Linting | `ruff check .` | 11 +| `mypy` | Static type checking | `mypy .` | 12 +| `pytest` + `pytest-cov` | Testing and coverage | `coverage run -m pytest && coverage report -m` | 13 +| `pre-commit` | Pre-commit hooks | `pre-commit run --all-files` | 14 + 15 +## Quality Gates 16 + 17 +- **Coverage**: `coverage run -m pytest` must achieve ≥ 90% on `temp_anomaly.py` 18 +- **Formatting**: `black --check .` must pass with no changes 19 +- **Linting**: `ruff check .` must report zero violations 20 +- **Types**: `mypy .` must report zero errors 21 +- **Pre-commit hooks**: must be installed (`pre-commit install`) and pass before every commit 22 + 23 +## Coding Rules 24 + 25 +1. **Docstrings**: every public function must have a docstring describing its purpose, parameters, and return value. 26 +2. **No stack traces for user errors**: all user-facing errors must be caught and printed as a clean message to stdout; `sys.exit` with the correct code. Never let an unhandled exception reach the user. 27 +3. **Error messages match spec exactly**: the text of every error message (usage, file errors, schema errors, ordering errors) must match the specification character-for-character, including punctuation and capitalisation. 28 + 29 +## Running the Full Check 30 + 31 +```bash 32 +source venv/bin/activate 33 +black --check . 34 +ruff check . 35 +mypy . 36 +coverage run -m pytest -q 37 +coverage report -m --fail-under=90 38 +``` ⏺ Now add the lightweight existence test: ⏺ Write(tests/test_docs.py) ⎿ Wrote 11 lines to tests/test_docs.py 1 from pathlib import Path 2 3 ROOT = Path(__file__).parent.parent 4 5 6 def test_readme_exists(): 7 assert (ROOT / "README.md").is_file() 8 9 10 def test_agents_exists(): … +1 line (ctrl+o to expand) ⏺ Bash(venv/bin/coverage run -m pytest -q && venv/bin/coverage report -m --include=temp_anomaly.py 2>&1) ⎿ ..................................................... [100%] 53 passed in 1.03s Name Stmts Miss Cover Missing … +4 lines (ctrl+o to expand) ⏺ 53 tests, 99% coverage. README and AGENTS are fully written — ready for human review. ✻ Worked for 33s ❯ commit ⏺ Bash(cd /Users/jbslanka/Documents/GitHub/claude_code_workshop && git add exercise_one/walkthrough/temp-anomaly/ && git commit -m "$(cat <<'EOF' Add direct main() tes…) ⎿ [main 237eaf2] Add direct main() tests, finalize README and AGENTS (prompts 14-15) 5 files changed, 274 insertions(+), 5 deletions(-) create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_docs.py create mode 100644 exercise_one/walkthrough/temp-anomaly/tests/test_main_direct.py ⎿ Shell cwd was reset to /Users/jbslanka/Documents/GitHub/claude_code_workshop/exercise_one/walkthrough ⏺ Committed as 237eaf2. ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── ❯ ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Sonnet 4.6 | walkthrough@main (+9 -1) | 123k/200k (61%) | effort: high | 5h 35% @2:00am | 7d 7% @mar 7, 9:00pm ⧉ In claude_session.txt