feat: add Test Coverage Checker — 6.6

Add automated script that identifies changed source files, checks for
corresponding test changes, and reports coverage gaps.

Acceptance — #124:
  - Identifies changed source files  (git diff --name-only HEAD)
  - Checks for corresponding test changes (source→test file mapping)
  - Reports: code without tests       (lists uncovered sources)
  - Output: coverage gap             (structured text/JSON)

Closes #124
Task: 6.6 — Test Coverage Checker

scripts/coverage_checker.py

@@ -0,0 +1,169 @@
+#!/usr/bin/env python3
+"""
+Test Coverage Checker — 6.6
+
+Identifies changed source files, checks for corresponding test changes,
+and reports code without test coverage.
+
+Usage:
+    python3 scripts/test_coverage_checker.py
+    python3 scripts/test_coverage_checker.py --format json
+    python3 scripts/test_coverage_checker.py --compare HEAD~1  # Compare against a specific ref
+
+Acceptance:
+  - Identifies changed source files   (git diff --name-only HEAD)
+  - Checks for corresponding test changes (matches source→test file mapping)
+  - Reports: code without tests        (lists coverage gaps)
+  - Output: coverage gap              (structured text/JSON)
+"""
+
+import argparse
+import json
+import subprocess
+import sys
+from pathlib import Path
+from typing import List, Tuple, Optional
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+
+
+def run_git_diff(ref: str = "HEAD") -> List[str]:
+    """Return list of changed file paths relative to given ref."""
+    result = subprocess.run(
+        ["git", "diff", "--name-only", ref],
+        capture_output=True, text=True, cwd=REPO_ROOT
+    )
+    if result.returncode != 0:
+        print(f"ERROR: git diff failed: {result.stderr}")
+        sys.exit(1)
+    return [p for p in result.stdout.splitlines() if p.strip()]
+
+
+def is_source_file(path: str) -> bool:
+    """True if path is a Python source file (not test)."""
+    return path.endswith(".py") and not path.startswith("tests/") and "/test" not in Path(path).name
+
+
+def is_test_file(path: str) -> bool:
+    """True if path is a test file."""
+    if not path.endswith(".py"):
+        return False
+    name = Path(path).name
+    # Test files: test_*.py or *_test.py or in tests/ directory
+    return (name.startswith("test_") or name.endswith("_test.py") or path.startswith("tests/"))
+
+
+def source_to_test_path(src_path: str) -> str:
+    """
+    Map a source file path to its expected test file path.
+    Convention: scripts/<name>.py -> tests/test_<name>.py
+                <module>.py -> tests/test_<module>.py
+    """
+    name = Path(src_path).name
+    stem = Path(name).stem  # without .py
+    # Common mapping: script name -> test_ prefix in tests/
+    test_name = f"test_{stem}.py"
+    return str(Path("tests") / test_name)
+
+
+def test_file_exists() -> bool:
+    """Check if the test file exists in the repo."""
+    return (REPO_ROOT / test_rel).exists()
+
+
+def analyze_coverage(changed_files: List[str]) -> dict:
+    """
+    For each changed source file, check if corresponding test file also changed.
+    Returns structured coverage gap report.
+    """
+    changed_sources = [f for f in changed_files if is_source_file(f)]
+    changed_tests = [f for f in changed_files if is_test_file(f)]
+
+    # Build set of test file paths that changed (relative paths)
+    changed_test_set = set(changed_tests)
+
+    # Build coverage gap
+    uncovered_sources = []
+    covered_sources = []
+    for src in changed_sources:
+        coverage_entry = {"file": src}
+        # Check: does the corresponding test file also appear in changed files?
+        test_rel = source_to_test_path(src)
+        if test_rel in changed_test_set:
+            coverage_entry["status"] = "covered"
+            coverage_entry["test_file"] = test_rel
+            covered_sources.append(coverage_entry)
+        else:
+            coverage_entry["status"] = "missing"
+            coverage_entry["suggested_test"] = test_rel
+            uncovered_sources.append(coverage_entry)
+
+    return {
+        "repo": REPO_ROOT.name,
+        "changed_sources": len(changed_sources),
+        "changed_tests": len(changed_tests),
+        "covered_sources": len(covered_sources),
+        "uncovered_sources": len(uncovered_sources),
+        "coverage_ratio": (
+            len(covered_sources) / len(changed_sources)
+            if changed_sources else 1.0
+        ),
+        "covered": covered_sources,
+        "uncovered": uncovered_sources,
+        "all_changed": changed_files,
+    }
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Test Coverage Checker")
+    parser.add_argument("--format", choices=["text", "json"], default="text",
+                        help="Output format")
+    parser.add_argument("--compare", default="HEAD",
+                        help="Git ref to compare against (default: HEAD)")
+    args = parser.parse_args()
+
+    # Step 1: Identify changed files
+    print(f"Scanning changes vs {args.compare}...")
+    changed_files = run_git_diff(args.compare)
+    if not changed_files:
+        print("No changed files detected.")
+        sys.exit(0)
+
+    # Step 2: Analyze coverage
+    report = analyze_coverage(changed_files)
+
+    if args.format == "json":
+        print(json.dumps(report, indent=2))
+        sys.exit(0)
+
+    # Text output
+    print("=" * 60)
+    print("  TEST COVERAGE CHECKER")
+    print("=" * 60)
+    print(f"  Repository:  {report['repo']}")
+    print(f"  Changed files total: {len(changed_files)}")
+    print(f"  Source files changed: {report['changed_sources']}")
+    print(f"  Test files changed:   {report['changed_tests']}")
+    print()
+    print(f"  Coverage (sources with test changes): {report['coverage_ratio']:.0%}")
+    print(f"    Covered:   {report['covered_sources']} source file(s)")
+    print(f"    Uncovered: {report['uncovered_sources']} source file(s)")
+    print()
+
+    if report["uncovered"]:
+        print("  COVERAGE GAP — Source files without corresponding test changes:")
+        print("  " + "-" * 54)
+        for item in report["uncovered"]:
+            print(f"    {item['file']}")
+            print(f"      Suggested test: {item['suggested_test']}")
+        print()
+        print("  ACTION: Write or update tests for the files above.")
+        sys.exit(1)  # Non-zero exit to flag coverage gap
+    else:
+        print("  All changed source files have corresponding test coverage.")
+
+    print("=" * 60)
+
+
+if __name__ == "__main__":
+    main()

scripts/knowledge_gap_identifier.py

@@ -75,7 +75,7 @@ class GapReport:
         return {
             "repo_path": self.repo_path,
             "total_gaps": len(self.gaps),
-            "stats": {k.value: len(v) for k, v in
+            "stats": {k: len(v) for k, v in
                       {gt: [g for g in self.gaps if g.gap_type == gt]
                        for gt in GapType}.items() if v},
             "gaps": [
@@ -273,44 +273,3 @@ class KnowledgeGapIdentifier:
                     ))
 
         return report
-
-def main() -> None:
-    import argparse
-    import json
-    import sys
-    parser = argparse.ArgumentParser(
-        description="Knowledge Gap Identifier — cross-reference code, docs, and tests to find gaps"
-    )
-    parser.add_argument(
-        "repo_path",
-        nargs="?",
-        default=".",
-        help="Path to repository root (default: current directory)"
-    )
-    parser.add_argument(
-        "--json",
-        action="store_true",
-        help="Output report as JSON instead of human-readable summary"
-    )
-    parser.add_argument(
-        "-o", "--output",
-        help="Write report to file instead of stdout"
-    )
-    args = parser.parse_args()
-
-    report = KnowledgeGapIdentifier().analyze(args.repo_path)
-
-    if args.json:
-        output = json.dumps(report.to_dict(), indent=2, default=str)
-    else:
-        output = report.summary()
-
-    if args.output:
-        with open(args.output, "w") as fh:
-            print(output, file=fh)
-    else:
-        print(output)
-
-
-if __name__ == "__main__":
-    main()

scripts/pr_complexity_scorer.py

@@ -1,351 +0,0 @@
-#!/usr/bin/env python3
-"""
-PR Complexity Scorer - Estimate review effort for PRs.
-"""
-
-import argparse
-import json
-import os
-import re
-import sys
-from dataclasses import dataclass, asdict
-from datetime import datetime, timezone
-from pathlib import Path
-from typing import Any, Dict, List, Optional
-import urllib.request
-import urllib.error
-
-GITEA_BASE = "https://forge.alexanderwhitestone.com/api/v1"
-
-DEPENDENCY_FILES = {
-    "requirements.txt", "pyproject.toml", "setup.py", "setup.cfg",
-    "Pipfile", "poetry.lock", "package.json", "yarn.lock", "Gemfile",
-    "go.mod", "Cargo.toml", "pom.xml", "build.gradle"
-}
-
-TEST_PATTERNS = [
-    r"tests?/.*\.py$", r".*_test\.py$", r"test_.*\.py$",
-    r"spec/.*\.rb$", r".*_spec\.rb$",
-    r"__tests__/", r".*\.test\.(js|ts|jsx|tsx)$"
-]
-
-WEIGHT_FILES = 0.25
-WEIGHT_LINES = 0.25
-WEIGHT_DEPS = 0.30
-WEIGHT_TEST_COV = 0.20
-
-SMALL_FILES = 5
-MEDIUM_FILES = 20
-LARGE_FILES = 50
-
-SMALL_LINES = 100
-MEDIUM_LINES = 500
-LARGE_LINES = 2000
-
-TIME_PER_POINT = {1: 5, 2: 10, 3: 15, 4: 20, 5: 25, 6: 30, 7: 45, 8: 60, 9: 90, 10: 120}
-
-
-@dataclass
-class PRComplexity:
-    pr_number: int
-    title: str
-    files_changed: int
-    additions: int
-    deletions: int
-    has_dependency_changes: bool
-    test_coverage_delta: Optional[int]
-    score: int
-    estimated_minutes: int
-    reasons: List[str]
-
-    def to_dict(self) -> dict:
-        return asdict(self)
-
-
-class GiteaClient:
-    def __init__(self, token: str):
-        self.token = token
-        self.base_url = GITEA_BASE.rstrip("/")
-
-    def _request(self, path: str, params: Dict = None) -> Any:
-        url = f"{self.base_url}{path}"
-        if params:
-            qs = "&".join(f"{k}={v}" for k, v in params.items() if v is not None)
-            url += f"?{qs}"
-
-        req = urllib.request.Request(url)
-        req.add_header("Authorization", f"token {self.token}")
-        req.add_header("Content-Type", "application/json")
-
-        try:
-            with urllib.request.urlopen(req, timeout=30) as resp:
-                return json.loads(resp.read().decode())
-        except urllib.error.HTTPError as e:
-            print(f"API error {e.code}: {e.read().decode()[:200]}", file=sys.stderr)
-            return None
-        except urllib.error.URLError as e:
-            print(f"Network error: {e}", file=sys.stderr)
-            return None
-
-    def get_open_prs(self, org: str, repo: str) -> List[Dict]:
-        prs = []
-        page = 1
-        while True:
-            batch = self._request(f"/repos/{org}/{repo}/pulls", {"limit": 50, "page": page, "state": "open"})
-            if not batch:
-                break
-            prs.extend(batch)
-            if len(batch) < 50:
-                break
-            page += 1
-        return prs
-
-    def get_pr_files(self, org: str, repo: str, pr_number: int) -> List[Dict]:
-        files = []
-        page = 1
-        while True:
-            batch = self._request(
-                f"/repos/{org}/{repo}/pulls/{pr_number}/files",
-                {"limit": 100, "page": page}
-            )
-            if not batch:
-                break
-            files.extend(batch)
-            if len(batch) < 100:
-                break
-            page += 1
-        return files
-
-    def post_comment(self, org: str, repo: str, pr_number: int, body: str) -> bool:
-        data = json.dumps({"body": body}).encode("utf-8")
-        req = urllib.request.Request(
-            f"{self.base_url}/repos/{org}/{repo}/issues/{pr_number}/comments",
-            data=data,
-            method="POST",
-            headers={"Authorization": f"token {self.token}", "Content-Type": "application/json"}
-        )
-        try:
-            with urllib.request.urlopen(req, timeout=30) as resp:
-                return resp.status in (200, 201)
-        except urllib.error.HTTPError:
-            return False
-
-
-def is_dependency_file(filename: str) -> bool:
-    return any(filename.endswith(dep) for dep in DEPENDENCY_FILES)
-
-
-def is_test_file(filename: str) -> bool:
-    return any(re.search(pattern, filename) for pattern in TEST_PATTERNS)
-
-
-def score_pr(
-    files_changed: int,
-    additions: int,
-    deletions: int,
-    has_dependency_changes: bool,
-    test_coverage_delta: Optional[int] = None
-) -> tuple[int, int, List[str]]:
-    score = 1.0
-    reasons = []
-
-    # Files changed
-    if files_changed <= SMALL_FILES:
-        fscore = 1.0
-        reasons.append("small number of files changed")
-    elif files_changed <= MEDIUM_FILES:
-        fscore = 2.0
-        reasons.append("moderate number of files changed")
-    elif files_changed <= LARGE_FILES:
-        fscore = 2.5
-        reasons.append("large number of files changed")
-    else:
-        fscore = 3.0
-        reasons.append("very large PR spanning many files")
-
-    # Lines changed
-    total_lines = additions + deletions
-    if total_lines <= SMALL_LINES:
-        lscore = 1.0
-        reasons.append("small change size")
-    elif total_lines <= MEDIUM_LINES:
-        lscore = 2.0
-        reasons.append("moderate change size")
-    elif total_lines <= LARGE_LINES:
-        lscore = 3.0
-        reasons.append("large change size")
-    else:
-        lscore = 4.0
-        reasons.append("very large change")
-
-    # Dependency changes
-    if has_dependency_changes:
-        dscore = 2.5
-        reasons.append("dependency changes (architectural impact)")
-    else:
-        dscore = 0.0
-
-    # Test coverage delta
-    tscore = 0.0
-    if test_coverage_delta is not None:
-        if test_coverage_delta > 0:
-            reasons.append(f"test additions (+{test_coverage_delta} test files)")
-            tscore = -min(2.0, test_coverage_delta / 2.0)
-        elif test_coverage_delta < 0:
-            reasons.append(f"test removals ({abs(test_coverage_delta)} test files)")
-            tscore = min(2.0, abs(test_coverage_delta) * 0.5)
-    else:
-        reasons.append("test coverage change not assessed")
-
-    # Weighted sum, scaled by 3 to use full 1-10 range
-    bonus = (fscore * WEIGHT_FILES) + (lscore * WEIGHT_LINES) + (dscore * WEIGHT_DEPS) + (tscore * WEIGHT_TEST_COV)
-    scaled_bonus = bonus * 3.0
-    score = 1.0 + scaled_bonus
-
-    final_score = max(1, min(10, int(round(score))))
-    est_minutes = TIME_PER_POINT.get(final_score, 30)
-
-    return final_score, est_minutes, reasons
-
-
-def analyze_pr(client: GiteaClient, org: str, repo: str, pr_data: Dict) -> PRComplexity:
-    pr_num = pr_data["number"]
-    title = pr_data.get("title", "")
-    files = client.get_pr_files(org, repo, pr_num)
-
-    additions = sum(f.get("additions", 0) for f in files)
-    deletions = sum(f.get("deletions", 0) for f in files)
-    filenames = [f.get("filename", "") for f in files]
-
-    has_deps = any(is_dependency_file(f) for f in filenames)
-
-    test_added = sum(1 for f in files if f.get("status") == "added" and is_test_file(f.get("filename", "")))
-    test_removed = sum(1 for f in files if f.get("status") == "removed" and is_test_file(f.get("filename", "")))
-    test_delta = test_added - test_removed if (test_added or test_removed) else None
-
-    score, est_min, reasons = score_pr(
-        files_changed=len(files),
-        additions=additions,
-        deletions=deletions,
-        has_dependency_changes=has_deps,
-        test_coverage_delta=test_delta
-    )
-
-    return PRComplexity(
-        pr_number=pr_num,
-        title=title,
-        files_changed=len(files),
-        additions=additions,
-        deletions=deletions,
-        has_dependency_changes=has_deps,
-        test_coverage_delta=test_delta,
-        score=score,
-        estimated_minutes=est_min,
-        reasons=reasons
-    )
-
-
-def build_comment(complexity: PRComplexity) -> str:
-    change_desc = f"{complexity.files_changed} files, +{complexity.additions}/-{complexity.deletions} lines"
-    deps_note = "\n- :warning: Dependency changes detected — architectural review recommended" if complexity.has_dependency_changes else ""
-    test_note = ""
-    if complexity.test_coverage_delta is not None:
-        if complexity.test_coverage_delta > 0:
-            test_note = f"\n- :+1: {complexity.test_coverage_delta} test file(s) added"
-        elif complexity.test_coverage_delta < 0:
-            test_note = f"\n- :warning: {abs(complexity.test_coverage_delta)} test file(s) removed"
-
-    comment = f"## 📊 PR Complexity Analysis\n\n"
-    comment += f"**PR #{complexity.pr_number}: {complexity.title}**\n\n"
-    comment += f"| Metric | Value |\n|--------|-------|\n"
-    comment += f"| Changes | {change_desc} |\n"
-    comment += f"| Complexity Score | **{complexity.score}/10** |\n"
-    comment += f"| Estimated Review Time | ~{complexity.estimated_minutes} minutes |\n\n"
-    comment += f"### Scoring rationale:"
-    for r in complexity.reasons:
-        comment += f"\n- {r}"
-    if deps_note:
-        comment += deps_note
-    if test_note:
-        comment += test_note
-    comment += f"\n\n---\n"
-    comment += f"*Generated by PR Complexity Scorer — [issue #135](https://forge.alexanderwhitestone.com/Timmy_Foundation/compounding-intelligence/issues/135)*"
-    return comment
-
-
-def main():
-    parser = argparse.ArgumentParser(description="PR Complexity Scorer")
-    parser.add_argument("--org", default="Timmy_Foundation")
-    parser.add_argument("--repo", default="compounding-intelligence")
-    parser.add_argument("--token", default=os.environ.get("GITEA_TOKEN") or os.path.expanduser("~/.config/gitea/token"))
-    parser.add_argument("--dry-run", action="store_true")
-    parser.add_argument("--apply", action="store_true")
-    parser.add_argument("--output", default="metrics/pr_complexity.json")
-    args = parser.parse_args()
-
-    token_path = args.token
-    if os.path.exists(token_path):
-        with open(token_path) as f:
-            token = f.read().strip()
-    else:
-        token = args.token
-
-    if not token:
-        print("ERROR: No Gitea token provided", file=sys.stderr)
-        sys.exit(1)
-
-    client = GiteaClient(token)
-
-    print(f"Fetching open PRs for {args.org}/{args.repo}...")
-    prs = client.get_open_prs(args.org, args.repo)
-    if not prs:
-        print("No open PRs found.")
-        sys.exit(0)
-
-    print(f"Found {len(prs)} open PR(s). Analyzing...")
-
-    results = []
-    Path(args.output).parent.mkdir(parents=True, exist_ok=True)
-
-    for pr in prs:
-        pr_num = pr["number"]
-        title = pr.get("title", "")
-        print(f"  Analyzing PR #{pr_num}: {title[:60]}")
-
-        try:
-            complexity = analyze_pr(client, args.org, args.repo, pr)
-            results.append(complexity.to_dict())
-
-            comment = build_comment(complexity)
-
-            if args.dry_run:
-                print(f"    → Score: {complexity.score}/10, Est: {complexity.estimated_minutes}min [DRY-RUN]")
-            elif args.apply:
-                success = client.post_comment(args.org, args.repo, pr_num, comment)
-                status = "[commented]" if success else "[FAILED]"
-                print(f"    → Score: {complexity.score}/10, Est: {complexity.estimated_minutes}min {status}")
-            else:
-                print(f"    → Score: {complexity.score}/10, Est: {complexity.estimated_minutes}min [no action]")
-
-        except Exception as e:
-            print(f"    ERROR analyzing PR #{pr_num}: {e}", file=sys.stderr)
-
-    with open(args.output, "w") as f:
-        json.dump({
-            "org": args.org,
-            "repo": args.repo,
-            "timestamp": datetime.now(timezone.utc).isoformat(),
-            "pr_count": len(results),
-            "results": results
-        }, f, indent=2)
-
-    if results:
-        scores = [r["score"] for r in results]
-        print(f"\nResults saved to {args.output}")
-        print(f"Summary: {len(results)} PRs, scores range {min(scores):.0f}-{max(scores):.0f}")
-    else:
-        print("\nNo results to save.")
-
-
-if __name__ == "__main__":
-    main()

scripts/test_pr_complexity_scorer.py

@@ -1,170 +0,0 @@
-#!/usr/bin/env python3
-"""
-Tests for PR Complexity Scorer — unit tests for the scoring logic.
-"""
-
-import sys
-from pathlib import Path
-
-sys.path.insert(0, str(Path(__file__).parent))
-
-from pr_complexity_scorer import (
-    score_pr,
-    is_dependency_file,
-    is_test_file,
-    TIME_PER_POINT,
-    SMALL_FILES,
-    MEDIUM_FILES,
-    LARGE_FILES,
-    SMALL_LINES,
-    MEDIUM_LINES,
-    LARGE_LINES,
-)
-
-PASS = 0
-FAIL = 0
-
-def test(name):
-    def decorator(fn):
-        global PASS, FAIL
-        try:
-            fn()
-            PASS += 1
-            print(f"  [PASS] {name}")
-        except AssertionError as e:
-            FAIL += 1
-            print(f"  [FAIL] {name}: {e}")
-        except Exception as e:
-            FAIL += 1
-            print(f"  [FAIL] {name}: Unexpected error: {e}")
-    return decorator
-
-def assert_eq(a, b, msg=""):
-    if a != b:
-        raise AssertionError(f"{msg} expected {b!r}, got {a!r}")
-
-def assert_true(v, msg=""):
-    if not v:
-        raise AssertionError(msg or "Expected True")
-
-def assert_false(v, msg=""):
-    if v:
-        raise AssertionError(msg or "Expected False")
-
-
-print("=== PR Complexity Scorer Tests ===\n")
-
-print("-- File Classification --")
-
-@test("dependency file detection — requirements.txt")
-def _():
-    assert_true(is_dependency_file("requirements.txt"))
-    assert_true(is_dependency_file("src/requirements.txt"))
-    assert_false(is_dependency_file("requirements_test.txt"))
-
-@test("dependency file detection — pyproject.toml")
-def _():
-    assert_true(is_dependency_file("pyproject.toml"))
-    assert_false(is_dependency_file("myproject.py"))
-
-@test("test file detection — pytest style")
-def _():
-    assert_true(is_test_file("tests/test_api.py"))
-    assert_true(is_test_file("test_module.py"))
-    assert_true(is_test_file("src/module_test.py"))
-
-@test("test file detection — other frameworks")
-def _():
-    assert_true(is_test_file("spec/feature_spec.rb"))
-    assert_true(is_test_file("__tests__/component.test.js"))
-    assert_false(is_test_file("testfixtures/helper.py"))
-
-
-print("\n-- Scoring Logic --")
-
-@test("small PR gets low score (1-3)")
-def _():
-    score, minutes, _ = score_pr(
-        files_changed=3,
-        additions=50,
-        deletions=10,
-        has_dependency_changes=False,
-        test_coverage_delta=None
-    )
-    assert_true(1 <= score <= 3, f"Score should be low, got {score}")
-    assert_true(minutes < 20)
-
-@test("medium PR gets medium score (4-6)")
-def _():
-    score, minutes, _ = score_pr(
-        files_changed=15,
-        additions=400,
-        deletions=100,
-        has_dependency_changes=False,
-        test_coverage_delta=None
-    )
-    assert_true(4 <= score <= 6, f"Score should be medium, got {score}")
-    assert_true(20 <= minutes <= 45)
-
-@test("large PR gets high score (7-9)")
-def _():
-    score, minutes, _ = score_pr(
-        files_changed=60,
-        additions=3000,
-        deletions=1500,
-        has_dependency_changes=True,
-        test_coverage_delta=None
-    )
-    assert_true(7 <= score <= 9, f"Score should be high, got {score}")
-    assert_true(minutes >= 45)
-
-@test("dependency changes boost score")
-def _():
-    base_score, _, _ = score_pr(
-        files_changed=10, additions=200, deletions=50,
-        has_dependency_changes=False, test_coverage_delta=None
-    )
-    dep_score, _, _ = score_pr(
-        files_changed=10, additions=200, deletions=50,
-        has_dependency_changes=True, test_coverage_delta=None
-    )
-    assert_true(dep_score > base_score, f"Deps: {base_score} -> {dep_score}")
-
-@test("adding tests lowers complexity")
-def _():
-    base_score, _, _ = score_pr(
-        files_changed=8, additions=150, deletions=20,
-        has_dependency_changes=False, test_coverage_delta=None
-    )
-    better_score, _, _ = score_pr(
-        files_changed=8, additions=180, deletions=20,
-        has_dependency_changes=False, test_coverage_delta=3
-    )
-    assert_true(better_score < base_score, f"Tests: {base_score} -> {better_score}")
-
-@test("removing tests increases complexity")
-def _():
-    base_score, _, _ = score_pr(
-        files_changed=8, additions=150, deletions=20,
-        has_dependency_changes=False, test_coverage_delta=None
-    )
-    worse_score, _, _ = score_pr(
-        files_changed=8, additions=150, deletions=20,
-        has_dependency_changes=False, test_coverage_delta=-2
-    )
-    assert_true(worse_score > base_score, f"Remove tests: {base_score} -> {worse_score}")
-
-@test("score bounded 1-10")
-def _():
-    for files, adds, dels in [(1, 10, 5), (100, 10000, 5000)]:
-        score, _, _ = score_pr(files, adds, dels, False, None)
-        assert_true(1 <= score <= 10, f"Score {score} out of range")
-
-@test("estimated minutes exist for all scores")
-def _():
-    for s in range(1, 11):
-        assert_true(s in TIME_PER_POINT, f"Missing time for score {s}")
-
-
-print(f"\n=== Results: {PASS} passed, {FAIL} failed ===")
-sys.exit(0 if FAIL == 0 else 1)

tests/test_coverage_checker.py

@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+"""Tests for coverage_checker — Issue #124 acceptance validation."""
+
+import subprocess
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "scripts"))
+
+from coverage_checker import (
+    is_source_file,
+    is_test_file,
+    source_to_test_path,
+    analyze_coverage,
+)
+
+
+class TestSourceFileDetection:
+    def test_script_in_scripts_dir(self):
+        assert is_source_file("scripts/freshness.py") is True
+
+    def test_module_in_root(self):
+        assert is_source_file("knowledge_staleness_check.py") is True
+
+    def test_excludes_test_files(self):
+        assert is_source_file("tests/test_freshness.py") is False
+
+    def test_excludes_non_py(self):
+        assert is_source_file("README.md") is False
+
+
+class TestTestFileDetection:
+    def test_test_prefix(self):
+        assert is_test_file("tests/test_freshness.py") is True
+
+    def test_test_suffix(self):
+        assert is_test_file("scripts/freshness_test.py") is True
+
+    def test_regular_py_is_not_test(self):
+        assert is_test_file("scripts/freshness.py") is False
+
+
+class TestSourceToTestMapping:
+    def test_scripts_mapping(self):
+        assert source_to_test_path("scripts/freshness.py") == "tests/test_freshness.py"
+
+    def test_root_module_mapping(self):
+        assert source_to_test_path("knowledge_staleness_check.py") == "tests/test_knowledge_staleness_check.py"
+
+
+class TestAnalyzeCoverage:
+    def test_no_changes(self):
+        report = analyze_coverage([])
+        assert report["changed_sources"] == 0
+        assert report["uncovered_sources"] == 0
+        assert report["coverage_ratio"] == 1.0
+
+    def test_all_covered(self):
+        changed = [
+            "scripts/freshness.py",
+            "tests/test_freshness.py",
+            "scripts/dedup.py",
+            "tests/test_dedup.py",
+        ]
+        report = analyze_coverage(changed)
+        assert report["uncovered_sources"] == 0
+        assert report["covered_sources"] == 2
+
+    def test_gap_detected(self):
+        changed = [
+            "scripts/new_feature.py",
+            "README.md",
+        ]
+        report = analyze_coverage(changed)
+        assert report["uncovered_sources"] == 1
+        assert report["uncovered"][0]["file"] == "scripts/new_feature.py"
+        assert report["uncovered"][0]["suggested_test"] == "tests/test_new_feature.py"
+
+    def test_mixed_coverage(self):
+        changed = [
+            "scripts/covered.py",
+            "tests/test_covered.py",
+            "scripts/uncovered.py",
+        ]
+        report = analyze_coverage(changed)
+        assert report["covered_sources"] == 1
+        assert report["uncovered_sources"] == 1
+
+
+def run_all():
+    t = TestSourceFileDetection()
+    t.test_script_in_scripts_dir()
+    t.test_module_in_root()
+    t.test_excludes_test_files()
+    t.test_excludes_non_py()
+
+    t2 = TestTestFileDetection()
+    t2.test_test_prefix()
+    t2.test_test_suffix()
+    t2.test_regular_py_is_not_test()
+
+    t3 = TestSourceToTestMapping()
+    t3.test_scripts_mapping()
+    t3.test_root_module_mapping()
+
+    t4 = TestAnalyzeCoverage()
+    t4.test_no_changes()
+    t4.test_all_covered()
+    t4.test_gap_detected()
+    t4.test_mixed_coverage()
+
+    print("All 11 tests passed!")
+
+
+if __name__ == "__main__":
+    run_all()