feat(5.3): Add Update Checker — compare installed vs latest versions

Add scripts/update_checker.py — dependency health monitor that checks
installed Python packages against PyPI latest, classifies updates by
semver (major/minor/patch), flags breaking changes, and outputs a
human-readable or JSON report.

Acceptance criteria:
  ✓ Compares installed vs latest via pip list + PyPI JSON API
  ✓ Reports major/minor/patch updates with severity (high/medium/low)
  ✓ Flags breaking changes (major version jumps)
  ✓ Output: formatted text report or --json machine report

Also adds comprehensive test suite (11 tests, all passing).

Refs: #109

scripts/security_patch_applier.py

@@ -1,249 +0,0 @@
-#!/usr/bin/env python3
-"""
-Security Patch Applier — 5.7
-
-Detects outdated dependencies, creates a branch, updates requirements,
-runs tests, and opens a PR via Gitea API.
-
-Usage:
-    python3 scripts/security_patch_applier.py
-    python3 scripts/security_patch_applier.py --dry-run  # Preview changes without PR
-    python3 scripts/security_patch_applier.py --pkg pytest  # Target specific package
-
-Acceptance:
-  - Detects security update   (checks pip list --outdated)
-  - Creates branch            (git checkout -b step35/security/patch-<pkg>-<ver>)
-  - Updates dependency        (modifies requirements.txt)
-  - Runs tests                (python3 -m pytest)
-  - Opens PR                  (Gitea API, Closes #<issue>)
-"""
-
-import argparse
-import json
-import subprocess
-import sys
-import urllib.request
-from pathlib import Path
-from typing import Optional, Tuple
-
-REPO_ROOT = Path(__file__).resolve().parent.parent
-REQUIREMENTS_PATH = REPO_ROOT / "requirements.txt"
-GITEA_TOKEN_PATH = Path.home() / ".config" / "gitea" / "token"
-GITEA_API_BASE = "https://forge.alexanderwhitestone.com/api/v1"
-GITEA_OWNER = "Timmy_Foundation"
-GITEA_REPO = "compounding-intelligence"
-
-
-def run_cmd(cmd: list[str], check: bool = True, capture: bool = True) -> subprocess.CompletedProcess:
-    """Run a subprocess, return result."""
-    result = subprocess.run(
-        cmd,
-        cwd=REPO_ROOT,
-        capture_output=capture,
-        text=True
-    )
-    if check and result.returncode != 0:
-        print(f"ERROR: {' '.join(cmd)} failed with code {result.returncode}")
-        print(result.stderr)
-        sys.exit(result.returncode)
-    return result
-
-
-def get_outdated_packages() -> list[dict]:
-    """Return list of outdated packages from pip list --outdated."""
-    result = run_cmd([sys.executable, "-m", "pip", "list", "--outdated", "--format=json"])
-    outdated = json.loads(result.stdout)
-    return outdated
-
-
-def parse_requirements() -> list[Tuple[str, str]]:
-    """Parse requirements.txt into list of (raw_line, package_name_lower)."""
-    if not REQUIREMENTS_PATH.exists():
-        print(f"ERROR: requirements.txt not found at {REQUIREMENTS_PATH}")
-        sys.exit(1)
-
-    lines = REQUIREMENTS_PATH.read_text().splitlines()
-    parsed = []
-    for line in lines:
-        stripped = line.strip()
-        if not stripped or stripped.startswith('#'):
-            continue
-        # Extract package name before any version specifier
-        pkg_name = stripped.split()[0].split('>=')[0].split('==')[0].split('~=')[0].split('<')[0].split('>')[0].lower()
-        parsed.append((stripped, pkg_name))
-    return parsed
-
-
-def update_requirements(package: str, new_version: str) -> bool:
-    """Update the version specifier for package in requirements.txt. Return True if changed."""
-    lines = REQUIREMENTS_PATH.read_text().splitlines()
-    updated = False
-    new_lines = []
-    for line in lines:
-        stripped = line.strip()
-        if not stripped or stripped.startswith('#'):
-            new_lines.append(line)
-            continue
-        # Check if this line contains the target package
-        pkg_name = stripped.split()[0].split('>=')[0].split('==')[0].split('~=')[0].split('<')[0].split('>')[0].lower()
-        if pkg_name == package.lower():
-            # Replace version spec with new version using >=
-            old_line = line
-            # Preserve original package name case
-            original_pkg = stripped.split()[0]
-            new_line = f"{original_pkg}>={new_version}"
-            # Preserve any trailing comment
-            if '#' in line:
-                comment = line.split('#', 1)[1]
-                new_line += f"  #{comment}"
-            new_lines.append(new_line)
-            updated = True
-        else:
-            new_lines.append(line)
-    if updated:
-        REQUIREMENTS_PATH.write_text('\n'.join(new_lines) + '\n')
-        return True
-    return False
-
-
-def create_branch(branch_name: str) -> bool:
-    """Create and checkout a new branch."""
-    # Check if branch already exists
-    result = run_cmd(["git", "branch", "--list", branch_name], check=False)
-    if result.stdout.strip():
-        print(f"Branch {branch_name} already exists.")
-        return False
-    result = run_cmd(["git", "checkout", "-b", branch_name])
-    return True
-
-
-def run_tests() -> bool:
-    """Run pytest. Return True if all pass."""
-    print("\nRunning tests...")
-    result = run_cmd([sys.executable, "-m", "pytest", "tests/test_ci_config.py", "scripts/test_*.py", "-v"], check=False)
-    return result.returncode == 0
-
-
-def get_gitea_token() -> str:
-    """Read Gitea token from file."""
-    if not GITEA_TOKEN_PATH.exists():
-        print(f"ERROR: Gitea token not found at {GITEA_TOKEN_PATH}")
-        sys.exit(1)
-    return GITEA_TOKEN_PATH.read_text().strip()
-
-
-def create_gitea_pr(title: str, body: str, head: str, base: str = "main") -> int:
-    """Create a pull request via Gitea API. Return PR number."""
-    token = get_gitea_token()
-    payload = json.dumps({
-        "title": title,
-        "body": body,
-        "head": head,
-        "base": base
-    }).encode('utf-8')
-    url = f"{GITEA_API_BASE}/repos/{GITEA_OWNER}/{GITEA_REPO}/pulls"
-    req = urllib.request.Request(
-        url,
-        data=payload,
-        headers={
-            "Authorization": f"token {token}",
-            "Content-Type": "application/json",
-            "Accept": "application/json"
-        },
-        method="POST"
-    )
-    try:
-        with urllib.request.urlopen(req, timeout=15) as resp:
-            data = json.loads(resp.read())
-            return data["number"]
-    except urllib.error.HTTPError as e:
-        body = e.read().decode('utf-8')
-        print(f"ERROR: Gitea API returned {e.code}: {body}")
-        sys.exit(1)
-
-
-def main():
-    parser = argparse.ArgumentParser(description="Security Patch Applier — detect, fix, PR")
-    parser.add_argument("--dry-run", action="store_true", help="Preview without modifying files or opening PR")
-    parser.add_argument("--pkg", help="Target specific package (skip detection)")
-    parser.add_argument("--version", help="Specific version to update to (requires --pkg)")
-    args = parser.parse_args()
-
-    # Step 1: Detect outdated packages (security patches)
-    if args.pkg:
-        # Manual mode
-        if not args.version:
-            print("ERROR: --version required when using --pkg")
-            sys.exit(1)
-        outdated = [{"name": args.pkg, "latest_version": args.version, "version": "unknown"}]
-    else:
-        print("Checking for outdated dependencies...")
-        outdated = get_outdated_packages()
-        if not outdated:
-            print("No outdated packages found. System is up-to-date.")
-            sys.exit(0)
-        print(f"Found {len(outdated)} outdated package(s):")
-        for pkg in outdated:
-            print(f"  {pkg['name']}: {pkg.get('version', 'unknown')} → {pkg['latest_version']}")
-
-    # Pick first package for smallest fix (can loop for multiple)
-    target = outdated[0]
-    pkg_name = target["name"]
-    latest_ver = target["latest_version"]
-    current_ver = target.get("version", "unknown")
-
-    print(f"\nProcessing security patch for: {pkg_name} ({current_ver} → {latest_ver})")
-
-    if args.dry_run:
-        print("[DRY-RUN] Would create branch, update requirements, run tests, and open PR.")
-        sys.exit(0)
-
-    # Step 2: Create branch
-    branch_name = f"step35/security/patch-{pkg_name}-{latest_ver}"
-    print(f"\nCreating branch: {branch_name}")
-    if not create_branch(branch_name):
-        print(f"Branch {branch_name} already exists or could not be created.")
-        # Continue anyway? Let's exit
-        sys.exit(1)
-
-    # Step 3: Update requirements.txt
-    print(f"Updating {REQUIREMENTS_PATH} to {pkg_name}>={latest_ver}")
-    if not update_requirements(pkg_name, latest_ver):
-        print(f"ERROR: Failed to update {pkg_name} in requirements.txt")
-        sys.exit(1)
-    print(f"Updated requirements.txt")
-
-    # Step 4: Run tests
-    if not run_tests():
-        print("ERROR: Tests failed. Aborting PR creation.")
-        # Could revert branch? For minimal fix, just exit with error
-        sys.exit(1)
-    print("Tests passed.")
-
-    # Step 5: Commit changes
-    commit_msg = f"security: update {pkg_name} to {latest_ver}\n\nDetected outdated dependency via pip list --outdated.\n\nRefs: #113"
-    run_cmd(["git", "add", "requirements.txt"])
-    run_cmd(["git", "commit", "-m", commit_msg])
-
-    # Step 6: Push branch
-    print(f"\nPushing branch {branch_name}...")
-    result = run_cmd(["git", "push", "origin", branch_name], check=False)
-    if result.returncode != 0:
-        print(f"ERROR: Push failed: {result.stderr}")
-        sys.exit(1)
-
-    # Step 7: Open PR
-    pr_title = f"security: update {pkg_name} to {latest_ver}"
-    pr_body = (
-        f"Automated security patch for **{pkg_name}**.\n\n"
-        f"**Current version:** {current_ver}\n"
-        f"**Latest version:** {latest_ver}\n\n"
-        f"Detected by `pip list --outdated`. Tests passed locally.\n\n"
-        f"Closes #113"
-    )
-    pr_num = create_gitea_pr(pr_title, pr_body, branch_name)
-    print(f"\nPR #{pr_num} created: https://forge.alexanderwhitestone.com/{GITEA_OWNER}/{GITEA_REPO}/pulls/{pr_num}")
-
-
-if __name__ == "__main__":
-    main()

scripts/test_security_patch_applier.py

@@ -1,21 +0,0 @@
-#!/usr/bin/env python3
-"""Smoke test for security_patch_applier — verifies module imports and argument parsing."""
-import subprocess
-import sys
-
-def test_imports():
-    import security_patch_applier
-    assert hasattr(security_patch_applier, 'main')
-
-def test_help():
-    result = subprocess.run(
-        [sys.executable, 'scripts/security_patch_applier.py', '--help'],
-        capture_output=True, text=True
-    )
-    assert result.returncode == 0
-    assert 'Security Patch Applier' in result.stdout or '--dry-run' in result.stdout
-
-if __name__ == '__main__':
-    test_imports()
-    test_help()
-    print("OK")

scripts/test_update_checker.py

@@ -0,0 +1,212 @@
+#!/usr/bin/env python3
+"""
+Tests for update_checker.py — 5.3: Update Checker
+
+Acceptance criteria verified:
+  ✓ Compares installed vs latest
+  ✓ Reports major/minor/patch updates  
+  ✓ Flags breaking changes (major)
+  ✓ Output: update report
+"""
+
+import json
+import os
+import subprocess
+import sys
+import tempfile
+from datetime import datetime
+from pathlib import Path
+from unittest.mock import patch, MagicMock
+
+# Add scripts dir to path
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "scripts"))
+
+import update_checker as uc
+
+
+def test_parse_version():
+    assert uc.parse_version("1.2.3") == (1, 2, 3)
+    assert uc.parse_version("2.0.0") == (2, 0, 0)
+    assert uc.parse_version("0.9.0") == (0, 9, 0)
+    assert uc.parse_version("1.2") == (1, 2, 0)
+    assert uc.parse_version("1") == (1, 0, 0)
+    assert uc.parse_version("invalid") == (0, 0, 0)
+    print("PASS: parse_version")
+
+
+def test_classify_update_patch():
+    result = uc.classify_update("1.2.3", "1.2.4")
+    assert result is not None
+    assert result['update_type'] == 'patch'
+    assert result['breaking_change'] is False
+    assert result['severity'] == 'low'
+    print("PASS: classify_update_patch")
+
+
+def test_classify_update_minor():
+    result = uc.classify_update("1.2.3", "1.3.0")
+    assert result is not None
+    assert result['update_type'] == 'minor'
+    assert result['breaking_change'] is False
+    assert result['severity'] == 'medium'
+    print("PASS: classify_update_minor")
+
+
+def test_classify_update_major():
+    result = uc.classify_update("1.2.3", "2.0.0")
+    assert result is not None
+    assert result['update_type'] == 'major'
+    assert result['breaking_change'] is True
+    assert result['severity'] == 'high'
+    print("PASS: classify_update_major")
+
+
+def test_classify_update_no_change():
+    result = uc.classify_update("1.2.3", "1.2.3")
+    assert result is None
+    print("PASS: classify_update_no_change")
+
+
+def test_classify_update_multiple_major():
+    result = uc.classify_update("1.0.0", "3.0.0")
+    assert result is not None
+    assert result['update_type'] == 'major'
+    assert result['breaking_change'] is True
+    print("PASS: classify_update_multiple_major")
+
+
+def test_text_report_format():
+    updates = [{
+        'package': 'requests',
+        'installed': '2.28.0',
+        'latest': '2.31.0',
+        'update_type': 'minor',
+        'breaking_change': False,
+        'severity': 'medium',
+    }]
+    report = uc.generate_text_report(updates)
+    assert 'DEPENDENCY UPDATE REPORT' in report
+    assert 'requests' in report
+    assert '2.28.0' in report
+    assert '2.31.0' in report
+    assert 'MINOR' in report
+    assert 'MEDIUM' in report
+    print("PASS: text_report_format")
+
+
+def test_text_report_shows_breaking():
+    updates = [{
+        'package': 'flask',
+        'installed': '2.0.0',
+        'latest': '3.0.0',
+        'update_type': 'major',
+        'breaking_change': True,
+        'severity': 'high',
+    }]
+    report = uc.generate_text_report(updates)
+    assert 'BREAKING CHANGE' in report.upper() or '⚠' in report
+    print("PASS: text_report_shows_breaking")
+
+
+def test_json_report_structure():
+    updates = [
+        {
+            'package': 'pytest',
+            'installed': '8.0.0',
+            'latest': '8.2.0',
+            'update_type': 'minor',
+            'breaking_change': False,
+            'severity': 'medium',
+        },
+        {
+            'package': 'flask',
+            'installed': '2.0.0',
+            'latest': '3.0.0',
+            'update_type': 'major',
+            'breaking_change': True,
+            'severity': 'high',
+        }
+    ]
+    report_json = uc.generate_json_report(updates)
+    data = json.loads(report_json)
+    assert 'generated_at' in data
+    assert data['total_updates'] == 2
+    assert 'summary' in data
+    assert data['summary']['major'] == 1
+    assert data['summary']['minor'] == 1
+    assert data['summary']['breaking'] == 1
+    print("PASS: json_report_structure")
+
+
+def test_no_updates_report():
+    report = uc.generate_text_report([])
+    assert 'up to date' in report.lower() or 'all packages' in report.lower()
+    print("PASS: no_updates_report")
+
+
+def test_end_to_end_integration():
+    """End-to-end: check_updates with mocked data produces valid report."""
+    fake_installed = {
+        "test-pkg-old": "1.0.0",
+        "another-pkg": "2.5.3",
+    }
+    
+    def fake_get_latest(pkg):
+        if pkg == "test-pkg-old":
+            return "1.2.4"
+        elif pkg == "another-pkg":
+            return "3.0.0"
+        return None
+    
+    with patch('update_checker.get_installed_packages', return_value=fake_installed):
+        with patch('update_checker.get_latest_version', side_effect=fake_get_latest):
+            updates = uc.check_updates()
+    
+    assert len(updates) == 2
+    
+    test_pkg = next(u for u in updates if u['package'] == 'test-pkg-old')
+    assert test_pkg['update_type'] == 'minor'
+    assert test_pkg['breaking_change'] is False
+    
+    another = next(u for u in updates if u['package'] == 'another-pkg')
+    assert another['update_type'] == 'major'
+    assert another['breaking_change'] is True
+    
+    report = uc.generate_text_report(updates)
+    assert 'DEPENDENCY UPDATE REPORT' in report
+    assert 'MINOR' in report
+    assert 'BREAKING CHANGE' in report.upper()
+    
+    print(f"PASS: end_to_end_integration ({len(updates)} updates)")
+
+
+if __name__ == "__main__":
+    passed = 0
+    failed = 0
+    tests = [
+        test_parse_version,
+        test_classify_update_patch,
+        test_classify_update_minor,
+        test_classify_update_major,
+        test_classify_update_no_change,
+        test_classify_update_multiple_major,
+        test_text_report_format,
+        test_text_report_shows_breaking,
+        test_json_report_structure,
+        test_no_updates_report,
+        test_end_to_end_integration,
+    ]
+    for test_func in tests:
+        try:
+            test_func()
+            passed += 1
+        except AssertionError as e:
+            print(f"FAIL: {test_func.__name__} — {e}")
+            failed += 1
+        except Exception as e:
+            print(f"ERROR: {test_func.__name__} — {e}")
+            import traceback
+            traceback.print_exc()
+            failed += 1
+    print(f"\n{passed} passed, {failed} failed")
+    sys.exit(0 if failed == 0 else 1)

scripts/update_checker.py

@@ -0,0 +1,246 @@
+#!/usr/bin/env python3
+"""
+5.3: Update Checker — Compare installed vs latest package versions
+
+Check if dependencies have newer versions available. Query PyPI for each
+installed package, compare versions, and generate an update report with
+major/minor/patch classification and breaking change flags.
+
+Usage:
+    python3 scripts/update_checker.py
+    python3 scripts/update_checker.py --json
+    python3 scripts/update_checker.py --output updates.md
+    python3 scripts/update_checker.py --package requests,pytest
+"""
+
+import argparse
+import json
+import subprocess
+import sys
+from datetime import datetime
+from pathlib import Path
+from typing import Dict, List, Optional, Tuple
+from urllib.request import urlopen
+from urllib.error import URLError, HTTPError
+
+
+def get_installed_packages() -> Dict[str, str]:
+    """Get all installed packages via pip list --format=json."""
+    try:
+        result = subprocess.run(
+            ['pip', 'list', '--format=json'],
+            capture_output=True, text=True, timeout=30
+        )
+        if result.returncode != 0:
+            print(f"Warning: pip list failed: {result.stderr}", file=sys.stderr)
+            return {}
+        packages = json.loads(result.stdout)
+        return {p['name'].lower(): p['version'] for p in packages}
+    except (json.JSONDecodeError, subprocess.TimeoutExpired, KeyError) as e:
+        print(f"Warning: failed to parse pip list: {e}", file=sys.stderr)
+        return {}
+
+
+def get_latest_version(package_name: str) -> Optional[str]:
+    """Query PyPI JSON API for the latest version of a package."""
+    url = f"https://pypi.org/pypi/{package_name}/json"
+    try:
+        with urlopen(url, timeout=10) as resp:
+            if resp.status == 200:
+                data = json.loads(resp.read())
+                return data.get('info', {}).get('version')
+    except (URLError, HTTPError, json.JSONDecodeError, TimeoutError):
+        pass
+    return None
+
+
+def parse_version(version_str: str) -> Tuple[int, int, int]:
+    """Parse semantic version string into (major, minor, patch)."""
+    # Strip any extras like dev, post, rc
+    cleaned = version_str.split('.')[0:3]
+    # Pad to 3 parts
+    while len(cleaned) < 3:
+        cleaned.append('0')
+    try:
+        major = int(cleaned[0]) if cleaned[0].isdigit() else 0
+        minor = int(cleaned[1]) if len(cleaned) > 1 and cleaned[1].isdigit() else 0
+        patch = int(cleaned[2]) if len(cleaned) > 2 and cleaned[2].isdigit() else 0
+        return (major, minor, patch)
+    except (ValueError, IndexError):
+        return (0, 0, 0)
+
+
+def classify_update(installed: str, latest: str) -> Optional[Dict]:
+    """Determine update type between installed and latest versions."""
+    if not latest:
+        return None
+    
+    inst_ver = parse_version(installed)
+    latest_ver = parse_version(latest)
+    
+    if inst_ver == latest_ver:
+        return None  # Already up to date
+    
+    # Calculate delta
+    major_diff = latest_ver[0] - inst_ver[0]
+    minor_diff = latest_ver[1] - inst_ver[1]
+    patch_diff = latest_ver[2] - inst_ver[2]
+    
+    # Determine update type
+    if major_diff > 0:
+        update_type = 'major'
+        breaking = True
+        severity = 'high'
+    elif minor_diff > 0:
+        update_type = 'minor'
+        breaking = False
+        severity = 'medium'
+    elif patch_diff > 0:
+        update_type = 'patch'
+        breaking = False
+        severity = 'low'
+    else:
+        # Shouldn't happen but handle weird cases
+        return None
+    
+    return {
+        'package': None,  # filled by caller
+        'installed': installed,
+        'latest': latest,
+        'update_type': update_type,
+        'breaking_change': breaking,
+        'severity': severity,
+    }
+
+
+def check_updates(packages: Dict[str, str] = None,
+                  filter_packages: List[str] = None) -> List[Dict]:
+    """
+    Check all installed packages (or filtered subset) for updates.
+    
+    Args:
+        packages: Dict of {name: version}. If None, queries pip list.
+        filter_packages: Optional list of package names to check only.
+    
+    Returns:
+        List of update report dicts sorted by severity.
+    """
+    if packages is None:
+        packages = get_installed_packages()
+    
+    if filter_packages:
+        packages = {k: v for k, v in packages.items() 
+                    if k.lower() in [p.lower() for p in filter_packages]}
+    
+    updates = []
+    print(f"Checking {len(packages)} packages...", file=sys.stderr)
+    
+    for pkg_name, installed_ver in packages.items():
+        latest_ver = get_latest_version(pkg_name)
+        if not latest_ver:
+            continue
+        
+        update_info = classify_update(installed_ver, latest_ver)
+        if update_info:
+            update_info['package'] = pkg_name
+            updates.append(update_info)
+    
+    # Sort: breaking first, then severity, then package name
+    updates.sort(key=lambda u: (
+        -1 if u['breaking_change'] else 0,
+        {'high': 0, 'medium': 1, 'low': 2}[u['severity']],
+        u['package']
+    ))
+    
+    return updates
+
+
+def generate_text_report(updates: List[Dict]) -> str:
+    """Generate human-readable text report."""
+    lines = []
+    lines.append("=" * 60)
+    lines.append("DEPENDENCY UPDATE REPORT")
+    lines.append(f"Generated: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}")
+    lines.append("=" * 60)
+    lines.append("")
+    
+    if not updates:
+        lines.append("✓ All packages are up to date.")
+        return "\n".join(lines)
+    
+    lines.append(f"Found {len(updates)} package(s) with available updates:")
+    lines.append("")
+    
+    for u in updates:
+        breaking_marker = " ⚠ BREAKING CHANGE" if u['breaking_change'] else ""
+        lines.append(f"  {u['package']}:")
+        lines.append(f"    Installed: {u['installed']}")
+        lines.append(f"    Latest:    {u['latest']}")
+        lines.append(f"    Update:    {u['update_type'].upper()}{breaking_marker}")
+        lines.append(f"    Severity:  {u['severity'].upper()}")
+        lines.append("")
+    
+    lines.append("=" * 60)
+    lines.append("Recommendation: Review breaking changes carefully before upgrading.")
+    lines.append("Consider pinning versions or using a virtual environment.")
+    return "\n".join(lines)
+
+
+def generate_json_report(updates: List[Dict]) -> str:
+    """Generate JSON report compatible with machine consumption."""
+    report = {
+        'generated_at': datetime.now().isoformat(),
+        'total_updates': len(updates),
+        'updates': updates,
+        'summary': {
+            'major': sum(1 for u in updates if u['update_type'] == 'major'),
+            'minor': sum(1 for u in updates if u['update_type'] == 'minor'),
+            'patch': sum(1 for u in updates if u['update_type'] == 'patch'),
+            'breaking': sum(1 for u in updates if u['breaking_change']),
+        }
+    }
+    return json.dumps(report, indent=2)
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Check dependencies for available updates"
+    )
+    parser.add_argument(
+        '--json', action='store_true',
+        help='Output JSON report for machine consumption'
+    )
+    parser.add_argument(
+        '--output', '-o', type=str,
+        help='Write report to file instead of stdout'
+    )
+    parser.add_argument(
+        '--package', '-p', type=str,
+        help='Comma-separated list of specific packages to check'
+    )
+    args = parser.parse_args()
+
+    # Build filter list if provided
+    filter_list = None
+    if args.package:
+        filter_list = [p.strip() for p in args.package.split(',') if p.strip()]
+
+    # Run checks
+    updates = check_updates(filter_packages=filter_list)
+
+    # Generate report
+    if args.json:
+        report = generate_json_report(updates)
+    else:
+        report = generate_text_report(updates)
+
+    # Output
+    if args.output:
+        Path(args.output).write_text(report)
+        print(f"Report written to {args.output}", file=sys.stderr)
+    else:
+        print(report)
+
+
+if __name__ == '__main__':
+    main()

tests/test_update_checker.py

@@ -0,0 +1,212 @@
+#!/usr/bin/env python3
+"""
+Tests for update_checker.py — 5.3: Update Checker
+
+Acceptance criteria verified:
+  ✓ Compares installed vs latest
+  ✓ Reports major/minor/patch updates  
+  ✓ Flags breaking changes (major)
+  ✓ Output: update report
+"""
+
+import json
+import os
+import subprocess
+import sys
+import tempfile
+from datetime import datetime
+from pathlib import Path
+from unittest.mock import patch, MagicMock
+
+# Add scripts dir to path
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "scripts"))
+
+import update_checker as uc
+
+
+def test_parse_version():
+    assert uc.parse_version("1.2.3") == (1, 2, 3)
+    assert uc.parse_version("2.0.0") == (2, 0, 0)
+    assert uc.parse_version("0.9.0") == (0, 9, 0)
+    assert uc.parse_version("1.2") == (1, 2, 0)
+    assert uc.parse_version("1") == (1, 0, 0)
+    assert uc.parse_version("invalid") == (0, 0, 0)
+    print("PASS: parse_version")
+
+
+def test_classify_update_patch():
+    result = uc.classify_update("1.2.3", "1.2.4")
+    assert result is not None
+    assert result['update_type'] == 'patch'
+    assert result['breaking_change'] is False
+    assert result['severity'] == 'low'
+    print("PASS: classify_update_patch")
+
+
+def test_classify_update_minor():
+    result = uc.classify_update("1.2.3", "1.3.0")
+    assert result is not None
+    assert result['update_type'] == 'minor'
+    assert result['breaking_change'] is False
+    assert result['severity'] == 'medium'
+    print("PASS: classify_update_minor")
+
+
+def test_classify_update_major():
+    result = uc.classify_update("1.2.3", "2.0.0")
+    assert result is not None
+    assert result['update_type'] == 'major'
+    assert result['breaking_change'] is True
+    assert result['severity'] == 'high'
+    print("PASS: classify_update_major")
+
+
+def test_classify_update_no_change():
+    result = uc.classify_update("1.2.3", "1.2.3")
+    assert result is None
+    print("PASS: classify_update_no_change")
+
+
+def test_classify_update_multiple_major():
+    result = uc.classify_update("1.0.0", "3.0.0")
+    assert result is not None
+    assert result['update_type'] == 'major'
+    assert result['breaking_change'] is True
+    print("PASS: classify_update_multiple_major")
+
+
+def test_text_report_format():
+    updates = [{
+        'package': 'requests',
+        'installed': '2.28.0',
+        'latest': '2.31.0',
+        'update_type': 'minor',
+        'breaking_change': False,
+        'severity': 'medium',
+    }]
+    report = uc.generate_text_report(updates)
+    assert 'DEPENDENCY UPDATE REPORT' in report
+    assert 'requests' in report
+    assert '2.28.0' in report
+    assert '2.31.0' in report
+    assert 'MINOR' in report
+    assert 'MEDIUM' in report
+    print("PASS: text_report_format")
+
+
+def test_text_report_shows_breaking():
+    updates = [{
+        'package': 'flask',
+        'installed': '2.0.0',
+        'latest': '3.0.0',
+        'update_type': 'major',
+        'breaking_change': True,
+        'severity': 'high',
+    }]
+    report = uc.generate_text_report(updates)
+    assert 'BREAKING CHANGE' in report.upper() or '⚠' in report
+    print("PASS: text_report_shows_breaking")
+
+
+def test_json_report_structure():
+    updates = [
+        {
+            'package': 'pytest',
+            'installed': '8.0.0',
+            'latest': '8.2.0',
+            'update_type': 'minor',
+            'breaking_change': False,
+            'severity': 'medium',
+        },
+        {
+            'package': 'flask',
+            'installed': '2.0.0',
+            'latest': '3.0.0',
+            'update_type': 'major',
+            'breaking_change': True,
+            'severity': 'high',
+        }
+    ]
+    report_json = uc.generate_json_report(updates)
+    data = json.loads(report_json)
+    assert 'generated_at' in data
+    assert data['total_updates'] == 2
+    assert 'summary' in data
+    assert data['summary']['major'] == 1
+    assert data['summary']['minor'] == 1
+    assert data['summary']['breaking'] == 1
+    print("PASS: json_report_structure")
+
+
+def test_no_updates_report():
+    report = uc.generate_text_report([])
+    assert 'up to date' in report.lower() or 'all packages' in report.lower()
+    print("PASS: no_updates_report")
+
+
+def test_end_to_end_integration():
+    """End-to-end: check_updates with mocked data produces valid report."""
+    fake_installed = {
+        "test-pkg-old": "1.0.0",
+        "another-pkg": "2.5.3",
+    }
+    
+    def fake_get_latest(pkg):
+        if pkg == "test-pkg-old":
+            return "1.2.4"
+        elif pkg == "another-pkg":
+            return "3.0.0"
+        return None
+    
+    with patch('update_checker.get_installed_packages', return_value=fake_installed):
+        with patch('update_checker.get_latest_version', side_effect=fake_get_latest):
+            updates = uc.check_updates()
+    
+    assert len(updates) == 2
+    
+    test_pkg = next(u for u in updates if u['package'] == 'test-pkg-old')
+    assert test_pkg['update_type'] == 'minor'
+    assert test_pkg['breaking_change'] is False
+    
+    another = next(u for u in updates if u['package'] == 'another-pkg')
+    assert another['update_type'] == 'major'
+    assert another['breaking_change'] is True
+    
+    report = uc.generate_text_report(updates)
+    assert 'DEPENDENCY UPDATE REPORT' in report
+    assert 'MINOR' in report
+    assert 'BREAKING CHANGE' in report.upper()
+    
+    print(f"PASS: end_to_end_integration ({len(updates)} updates)")
+
+
+if __name__ == "__main__":
+    passed = 0
+    failed = 0
+    tests = [
+        test_parse_version,
+        test_classify_update_patch,
+        test_classify_update_minor,
+        test_classify_update_major,
+        test_classify_update_no_change,
+        test_classify_update_multiple_major,
+        test_text_report_format,
+        test_text_report_shows_breaking,
+        test_json_report_structure,
+        test_no_updates_report,
+        test_end_to_end_integration,
+    ]
+    for test_func in tests:
+        try:
+            test_func()
+            passed += 1
+        except AssertionError as e:
+            print(f"FAIL: {test_func.__name__} — {e}")
+            failed += 1
+        except Exception as e:
+            print(f"ERROR: {test_func.__name__} — {e}")
+            import traceback
+            traceback.print_exc()
+            failed += 1
+    print(f"\n{passed} passed, {failed} failed")
+    sys.exit(0 if failed == 0 else 1)