US01-07: Automate Phase A End-to-End Acceptance (#53)

tests/e2e/test_traceability.py

@@ -0,0 +1,40 @@
+"""Story-to-test traceability for Phase A (Epic E01).
+
+Every story US01-01..US01-07 must map to test files that exist, and every Phase A
+test file must be claimed by a story — so a new test can't go unexercised and a
+story can't quietly lose its coverage. Whether those tests *pass* is proven by
+running the suite; this guards the mapping's completeness.
+"""
+
+import json
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parents[2]
+MAP = json.loads((REPO / "tests" / "phase_a_traceability.json").read_text())["stories"]
+EXPECTED_STORIES = {f"US01-0{n}" for n in range(1, 8)}
+
+
+def test_all_phase_a_stories_are_mapped():
+    assert set(MAP) == EXPECTED_STORIES
+
+
+def test_every_mapped_test_file_exists_and_is_nonempty():
+    for story, files in MAP.items():
+        assert files, f"{story} maps to no tests"
+        for rel in files:
+            path = REPO / rel
+            assert path.is_file(), f"{story}: missing {rel}"
+            assert path.stat().st_size > 0, f"{story}: empty {rel}"
+            assert "def test_" in path.read_text(), f"{story}: no tests in {rel}"
+
+
+def test_no_unexercised_phase_a_test_files():
+    """Every test_*.py under tests/ is claimed by a story (no orphan coverage)."""
+    mapped = {rel for files in MAP.values() for rel in files}
+    on_disk = {
+        str(p.relative_to(REPO))
+        for p in (REPO / "tests").rglob("test_*.py")
+        if "__pycache__" not in p.parts
+    }
+    unmapped = on_disk - mapped
+    assert not unmapped, f"test files not tied to any story: {sorted(unmapped)}"