test: enforce model and CLI boundary contracts

tests/test_coverage_thresholds.py

@@ -13,35 +13,42 @@ MODULE = importlib.util.module_from_spec(SPEC)
 SPEC.loader.exec_module(MODULE)
 
 
-def _report(line: float = 49.0, branch: float = 36.0) -> dict[str, object]:
+def _report(line: float = 55.0, branch: float = 42.0) -> dict[str, object]:
     return {
         "totals": {
             "percent_statements_covered": line,
             "percent_branches_covered": branch,
         },
+        "files": {
+            "obliteratus/example.py": {
+                "summary": {"percent_statements_covered": 70.0},
+                "executed_lines": [1, 2, 4],
+                "missing_lines": [3],
+            },
+        },
     }
 
 
 def test_validate_coverage_accepts_exact_floors():
     assert MODULE.validate_coverage(
-        _report(), min_line=49.0, min_branch=36.0,
+        _report(), min_line=55.0, min_branch=42.0,
     ) == []
 
 
 def test_validate_coverage_reports_each_regression():
     failures = MODULE.validate_coverage(
-        _report(line=48.9, branch=35.9), min_line=49.0, min_branch=36.0,
+        _report(line=54.9, branch=41.9), min_line=55.0, min_branch=42.0,
     )
 
     assert failures == [
-        "line coverage 48.90% is below the 49.00% floor",
-        "branch coverage 35.90% is below the 36.00% floor",
+        "line coverage 54.90% is below the 55.00% floor",
+        "branch coverage 41.90% is below the 42.00% floor",
     ]
 
 
 def test_validate_coverage_rejects_malformed_totals():
     assert MODULE.validate_coverage(
-        {}, min_line=49.0, min_branch=36.0,
+        {}, min_line=55.0, min_branch=42.0,
     ) == ["coverage report is missing the totals object"]
 
 
@@ -51,8 +58,56 @@ def test_validate_coverage_rejects_non_numeric_metrics():
     report["totals"]["percent_branches_covered"] = float("nan")
 
     assert MODULE.validate_coverage(
-        report, min_line=49.0, min_branch=36.0,
+        report, min_line=55.0, min_branch=42.0,
     ) == [
         "coverage report is missing numeric percent_statements_covered",
         "coverage report is missing numeric percent_branches_covered",
     ]
+
+
+def test_validate_coverage_enforces_critical_file_floors():
+    assert MODULE.validate_coverage(
+        _report(),
+        min_line=55.0,
+        min_branch=42.0,
+        file_floors={"obliteratus/example.py": 70.0},
+    ) == []
+
+    report = _report()
+    report["files"]["obliteratus/example.py"]["summary"]["percent_statements_covered"] = 69.9
+    assert MODULE.validate_coverage(
+        report,
+        min_line=55.0,
+        min_branch=42.0,
+        file_floors={"obliteratus/example.py": 70.0, "missing.py": 70.0},
+    ) == [
+        "critical file obliteratus/example.py coverage 69.90% is below the 70.00% floor",
+        "coverage report is missing critical file missing.py",
+    ]
+
+
+def test_parse_changed_lines_and_measurement_ignore_non_executable_lines():
+    diff = """diff --git a/obliteratus/example.py b/obliteratus/example.py
++++ b/obliteratus/example.py
+@@ -1,2 +1,4 @@
+diff --git a/tests/test_example.py b/tests/test_example.py
++++ b/tests/test_example.py
+@@ -0,0 +1,2 @@
+"""
+    changed = MODULE.parse_changed_lines(diff)
+    assert changed == {
+        "obliteratus/example.py": {1, 2, 3, 4},
+        "tests/test_example.py": {1, 2},
+    }
+    assert MODULE.changed_line_coverage(_report(), changed) == (3, 4, 75.0)
+    assert MODULE.validate_changed_coverage(
+        _report(), changed, minimum=90.0,
+    ) == ["changed-line coverage 75.00% (3/4) is below the 90.00% floor"]
+
+
+def test_changed_line_gate_passes_when_diff_has_no_measured_source():
+    assert MODULE.changed_line_coverage(_report(), {"tests/test_example.py": {1}}) == (
+        0,
+        0,
+        100.0,
+    )