test: add quality-depth gates and mature CPU coverage

tests/test_coverage_thresholds.py

@@ -2,15 +2,7 @@
 
 from __future__ import annotations
 
-import importlib.util
-from pathlib import Path
-
-
-SCRIPT = Path(__file__).parents[1] / "scripts" / "check_coverage_thresholds.py"
-SPEC = importlib.util.spec_from_file_location("check_coverage_thresholds", SCRIPT)
-assert SPEC is not None and SPEC.loader is not None
-MODULE = importlib.util.module_from_spec(SPEC)
-SPEC.loader.exec_module(MODULE)
+from scripts import check_coverage_thresholds as MODULE
 
 
 def _report(line: float = 55.0, branch: float = 42.0) -> dict[str, object]:
@@ -86,6 +78,30 @@ def test_validate_coverage_enforces_critical_file_floors():
     ]
 
 
+def test_critical_file_validation_continues_and_rejects_malformed_values():
+    report = _report()
+    report["files"]["bool.py"] = {
+        "summary": {"percent_statements_covered": True},
+    }
+    report["files"]["text.py"] = {
+        "summary": {"percent_statements_covered": "70"},
+    }
+    assert MODULE.validate_coverage(
+        report,
+        min_line=55.0,
+        min_branch=42.0,
+        file_floors={
+            "missing.py": 70.0,
+            "bool.py": 70.0,
+            "text.py": 70.0,
+        },
+    ) == [
+        "coverage report is missing critical file missing.py",
+        "coverage report is missing numeric line coverage for bool.py",
+        "coverage report is missing numeric line coverage for text.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
@@ -111,3 +127,41 @@ def test_changed_line_gate_passes_when_diff_has_no_measured_source():
         0,
         100.0,
     )
+
+
+def test_changed_line_parser_ignores_hunks_before_paths_and_defaults_count_to_one():
+    diff = """@@ -1 +99 @@
++++ b/obliteratus/example.py
+@@ -2 +3 @@
+"""
+    assert MODULE.parse_changed_lines(diff) == {"obliteratus/example.py": {3}}
+
+
+def test_changed_line_measurement_handles_missing_fields_and_multiple_files():
+    report = {
+        "files": {
+            "obliteratus/no-fields.py": {"summary": {}},
+            "obliteratus/first.py": {
+                "executed_lines": [1],
+                "missing_lines": [2],
+            },
+            "obliteratus/second.py": {
+                "executed_lines": [4],
+                "missing_lines": [5],
+            },
+        },
+    }
+    changed = {
+        "missing-entry.py": {1},
+        "obliteratus/no-fields.py": {1},
+        "obliteratus/first.py": {1, 2, 99},
+        "obliteratus/second.py": {4, 5, 100},
+    }
+    assert MODULE.changed_line_coverage(report, changed) == (2, 4, 50.0)
+
+
+def test_changed_line_gate_accepts_exact_floor():
+    changed = {"obliteratus/example.py": {1, 2, 3, 4}}
+    assert MODULE.validate_changed_coverage(
+        _report(), changed, minimum=75.0,
+    ) == []