feat: Add test scripts and runner for TheChart application

- Created demo_failing_test.py to demonstrate pre-commit blocking with a failing test.
- Added run_tests.py for executing all tests with coverage reporting.
- Introduced test.py as a quick test runner for the application, providing coverage reports and user-friendly output.

scripts/test.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+"""
+Quick test runner for TheChart application.
+This script provides a simple way to run the test suite.
+"""
+
+import os
+import subprocess
+import sys
+
+
+def main():
+    """Run the test suite."""
+    print("🧪 Running TheChart Test Suite")
+    print("=" * 50)
+
+    # Change to project directory
+    os.chdir(os.path.dirname(os.path.abspath(__file__)))
+
+    # Run tests with coverage
+    cmd = [
+        "uv",
+        "run",
+        "pytest",
+        "tests/",
+        "--cov=src",
+        "--cov-report=term-missing",
+        "--cov-report=html:htmlcov",
+        "-v",
+    ]
+
+    try:
+        result = subprocess.run(cmd, check=False)
+        if result.returncode == 0:
+            print("\n✅ All tests passed!")
+        else:
+            print(f"\n❌ Some tests failed (exit code: {result.returncode})")
+
+        print("\n📊 Coverage report generated in htmlcov/index.html")
+        return result.returncode
+
+    except KeyboardInterrupt:
+        print("\n⚠️  Tests interrupted by user")
+        return 1
+    except Exception as e:
+        print(f"\n💥 Error running tests: {e}")
+        return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())