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/run_tests.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+"""
+Test runner script for TheChart application.
+Run this script to execute all tests with coverage reporting.
+"""
+
+import os
+import subprocess
+import sys
+
+
+def run_tests():
+    """Run all tests with coverage reporting."""
+
+    # Change to project root directory
+    project_root = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+    os.chdir(project_root)
+
+    print("Running TheChart tests with coverage...")
+    print(f"Project root: {project_root}")
+
+    # Run pytest with coverage
+    cmd = [
+        sys.executable,
+        "-m",
+        "pytest",
+        "tests/",
+        "--verbose",
+        "--cov=src",
+        "--cov-report=term-missing",
+        "--cov-report=html:htmlcov",
+        "--cov-report=xml",
+    ]
+
+    try:
+        result = subprocess.run(cmd, check=False)
+        return result.returncode
+    except Exception as e:
+        print(f"Error running tests: {e}")
+        return 1
+
+
+if __name__ == "__main__":
+    exit_code = run_tests()
+    sys.exit(exit_code)