Add comprehensive test coverage for CLI utilities

Expand test suite from 118 to 166 tests (+48 new tests) with focus on
untested CLI tools and utility functions. Overall coverage increased
from 14% to 25%.

New test files:
- tests/test_utilities.py (42 tests) - API keys, file validation, formatting
- tests/test_package_skill.py (11 tests) - Skill packaging workflow
- tests/test_estimate_pages.py (8 tests) - Page estimation functionality
- tests/test_upload_skill.py (7 tests) - Skill upload validation

Coverage improvements by module:
- cli/utils.py: 0% → 72% (+72%)
- cli/upload_skill.py: 0% → 53% (+53%)
- cli/estimate_pages.py: 0% → 47% (+47%)
- cli/package_skill.py: 0% → 43% (+43%)

All 166 tests passing. Added pytest-cov for coverage reporting.
Updated requirements.txt with all dependencies including MCP packages.

Test execution: 9.6s for complete suite

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/test_upload_skill.py

@@ -0,0 +1,142 @@
+#!/usr/bin/env python3
+"""
+Tests for cli/upload_skill.py functionality
+"""
+
+import unittest
+import tempfile
+import zipfile
+import os
+from pathlib import Path
+import sys
+
+# Add cli directory to path
+sys.path.insert(0, str(Path(__file__).parent.parent / 'cli'))
+
+from upload_skill import upload_skill_api
+
+
+class TestUploadSkillAPI(unittest.TestCase):
+    """Test upload_skill_api function"""
+
+    def setUp(self):
+        """Store original API key state"""
+        self.original_api_key = os.environ.get('ANTHROPIC_API_KEY')
+
+    def tearDown(self):
+        """Restore original API key state"""
+        if self.original_api_key:
+            os.environ['ANTHROPIC_API_KEY'] = self.original_api_key
+        elif 'ANTHROPIC_API_KEY' in os.environ:
+            del os.environ['ANTHROPIC_API_KEY']
+
+    def create_test_zip(self, tmpdir):
+        """Helper to create a test .zip file"""
+        zip_path = Path(tmpdir) / "test-skill.zip"
+
+        with zipfile.ZipFile(zip_path, 'w') as zf:
+            zf.writestr("SKILL.md", "---\nname: test\n---\n# Test Skill")
+            zf.writestr("references/index.md", "# Index")
+
+        return zip_path
+
+    def test_upload_without_api_key(self):
+        """Test that upload fails gracefully without API key"""
+        # Remove API key
+        if 'ANTHROPIC_API_KEY' in os.environ:
+            del os.environ['ANTHROPIC_API_KEY']
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            zip_path = self.create_test_zip(tmpdir)
+
+            success, message = upload_skill_api(zip_path)
+
+            self.assertFalse(success)
+            # Check for api_key (with underscore) in message
+            self.assertTrue('api_key' in message.lower() or 'api key' in message.lower())
+
+    def test_upload_with_nonexistent_file(self):
+        """Test upload with nonexistent file"""
+        os.environ['ANTHROPIC_API_KEY'] = 'sk-ant-test-key'
+
+        success, message = upload_skill_api("/nonexistent/file.zip")
+
+        self.assertFalse(success)
+        self.assertIn('not found', message.lower())
+
+    def test_upload_with_invalid_zip(self):
+        """Test upload with invalid zip file (not a zip)"""
+        os.environ['ANTHROPIC_API_KEY'] = 'sk-ant-test-key'
+
+        with tempfile.NamedTemporaryFile(suffix='.zip', delete=False) as tmpfile:
+            tmpfile.write(b"Not a valid zip file")
+            tmpfile.flush()
+
+            try:
+                success, message = upload_skill_api(tmpfile.name)
+
+                # Should either fail validation or detect invalid zip
+                self.assertFalse(success)
+            finally:
+                os.unlink(tmpfile.name)
+
+    def test_upload_accepts_path_object(self):
+        """Test that upload_skill_api accepts Path objects"""
+        os.environ['ANTHROPIC_API_KEY'] = 'sk-ant-test-key'
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            zip_path = self.create_test_zip(tmpdir)
+
+            # This should not raise TypeError
+            try:
+                success, message = upload_skill_api(Path(zip_path))
+            except TypeError:
+                self.fail("upload_skill_api should accept Path objects")
+
+
+class TestUploadSkillCLI(unittest.TestCase):
+    """Test upload_skill.py command-line interface"""
+
+    def test_cli_help_output(self):
+        """Test that --help works"""
+        import subprocess
+
+        result = subprocess.run(
+            ['python3', 'cli/upload_skill.py', '--help'],
+            capture_output=True,
+            text=True
+        )
+
+        self.assertEqual(result.returncode, 0)
+        self.assertIn('usage:', result.stdout.lower())
+
+    def test_cli_executes_without_errors(self):
+        """Test that script can be executed"""
+        import subprocess
+
+        result = subprocess.run(
+            ['python3', 'cli/upload_skill.py', '--help'],
+            capture_output=True,
+            text=True
+        )
+
+        self.assertEqual(result.returncode, 0)
+
+    def test_cli_requires_zip_argument(self):
+        """Test that CLI requires zip file argument"""
+        import subprocess
+
+        result = subprocess.run(
+            ['python3', 'cli/upload_skill.py'],
+            capture_output=True,
+            text=True
+        )
+
+        # Should fail or show usage
+        self.assertTrue(
+            result.returncode != 0 or 'usage' in result.stderr.lower() or 'usage' in result.stdout.lower()
+        )
+
+
+if __name__ == '__main__':
+    unittest.main()