New unit tests

1-5-running-docker-compose/app-python/Dockerfile.test

@@ -0,0 +1,14 @@
+# Dockerfile for running tests
+FROM python:3.9-slim
+
+WORKDIR /app
+
+# Copy requirements and install dependencies
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy application code and tests
+COPY . .
+
+# Run tests by default
+CMD ["python", "-m", "pytest", "-v", "test_app.py"]

1-5-running-docker-compose/app-python/requirements.txt

@@ -1,2 +1,5 @@
 Flask
-Redis
+Redis
+pytest>=7.4.0
+pytest-flask>=1.2.0
+pytest-mock>=3.11.0

1-5-running-docker-compose/app-python/test_app.py

@@ -0,0 +1,206 @@
+"""
+Unit tests for the Flask application using unittest framework.
+
+This test suite covers:
+- Flask route functionality
+- Redis connection and counter behavior
+- Error handling for Redis failures
+- Environment variable handling
+"""
+
+import unittest
+from unittest.mock import patch, MagicMock
+import os
+from redis import RedisError
+from app import app
+
+
+class TestFlaskApp(unittest.TestCase):
+    """Test suite for the Flask application."""
+
+    def setUp(self):
+        """Set up test client and test environment."""
+        self.app = app
+        self.app.config['TESTING'] = True
+        self.client = self.app.test_client()
+
+    def tearDown(self):
+        """Clean up after tests."""
+        # Remove any environment variables set during tests
+        if 'NAME' in os.environ:
+            del os.environ['NAME']
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_hello_route_success(self, mock_hostname, mock_redis):
+        """Test successful request to hello route with Redis working."""
+        # Arrange
+        mock_redis.incr.return_value = 5
+        mock_hostname.return_value = 'test-container'
+        os.environ['NAME'] = 'TestUser'
+
+        # Act
+        response = self.client.get('/')
+
+        # Assert
+        self.assertEqual(response.status_code, 200)
+        self.assertIn(b'TestUser', response.data)
+        self.assertIn(b'test-container', response.data)
+        self.assertIn(b'5', response.data)
+        mock_redis.incr.assert_called_once_with('counter')
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_hello_route_redis_error(self, mock_hostname, mock_redis):
+        """Test hello route when Redis connection fails."""
+        # Arrange
+        mock_redis.incr.side_effect = RedisError('Connection failed')
+        mock_hostname.return_value = 'test-container'
+        os.environ['NAME'] = 'TestUser'
+
+        # Act
+        response = self.client.get('/')
+
+        # Assert
+        self.assertEqual(response.status_code, 200)
+        self.assertIn(b'cannot connect to Redis, counter disabled', response.data)
+        self.assertIn(b'TestUser', response.data)
+        self.assertIn(b'test-container', response.data)
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_hello_route_default_name(self, mock_hostname, mock_redis):
+        """Test hello route with default NAME environment variable."""
+        # Arrange
+        mock_redis.incr.return_value = 1
+        mock_hostname.return_value = 'test-container'
+        # Ensure NAME is not set
+        if 'NAME' in os.environ:
+            del os.environ['NAME']
+
+        # Act
+        response = self.client.get('/')
+
+        # Assert
+        self.assertEqual(response.status_code, 200)
+        self.assertIn(b'world', response.data)  # Default value
+        self.assertIn(b'test-container', response.data)
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_hello_route_counter_increments(self, mock_hostname, mock_redis):
+        """Test that Redis counter increments on multiple requests."""
+        # Arrange
+        mock_hostname.return_value = 'test-container'
+        counter_values = [1, 2, 3]
+        mock_redis.incr.side_effect = counter_values
+
+        # Act & Assert
+        for expected_count in counter_values:
+            response = self.client.get('/')
+            self.assertEqual(response.status_code, 200)
+            self.assertIn(str(expected_count).encode(), response.data)
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_hello_route_custom_hostname(self, mock_hostname, mock_redis):
+        """Test that the actual hostname is displayed correctly."""
+        # Arrange
+        mock_redis.incr.return_value = 1
+        custom_hostname = 'my-custom-docker-container-xyz'
+        mock_hostname.return_value = custom_hostname
+
+        # Act
+        response = self.client.get('/')
+
+        # Assert
+        self.assertEqual(response.status_code, 200)
+        self.assertIn(custom_hostname.encode(), response.data)
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_hello_route_special_characters_in_name(self, mock_hostname, mock_redis):
+        """Test hello route with special characters in NAME."""
+        # Arrange
+        mock_redis.incr.return_value = 1
+        mock_hostname.return_value = 'test-container'
+        os.environ['NAME'] = 'Test & User <123>'
+
+        # Act
+        response = self.client.get('/')
+
+        # Assert
+        self.assertEqual(response.status_code, 200)
+        # Flask auto-escapes HTML, so we check for escaped content
+        self.assertIn(b'Test', response.data)
+
+    def test_app_configuration(self):
+        """Test that Flask app is properly configured."""
+        # Assert
+        self.assertIsNotNone(self.app)
+        self.assertTrue(self.app.config['TESTING'])
+
+    @patch('app.redis')
+    def test_redis_connection_parameters(self, mock_redis):
+        """Test that Redis is configured with correct parameters."""
+        # This test verifies the Redis initialization in app.py
+        # The actual connection is made at module level
+        from app import redis as app_redis
+        # Just verify redis object exists
+        self.assertIsNotNone(app_redis)
+
+
+class TestFlaskAppIntegration(unittest.TestCase):
+    """Integration tests for Flask app endpoints."""
+
+    def setUp(self):
+        """Set up test client."""
+        self.app = app
+        self.app.config['TESTING'] = True
+        self.client = self.app.test_client()
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_multiple_requests_sequence(self, mock_hostname, mock_redis):
+        """Test a sequence of multiple requests to verify consistency."""
+        # Arrange
+        mock_hostname.return_value = 'test-container'
+        mock_redis.incr.side_effect = [1, 2, 3, 4, 5]
+
+        # Act
+        responses = [self.client.get('/') for _ in range(5)]
+
+        # Assert
+        for response in responses:
+            self.assertEqual(response.status_code, 200)
+        self.assertEqual(mock_redis.incr.call_count, 5)
+
+    @patch('app.redis')
+    @patch('app.socket.gethostname')
+    def test_redis_intermittent_failure(self, mock_hostname, mock_redis):
+        """Test handling of intermittent Redis failures."""
+        # Arrange
+        mock_hostname.return_value = 'test-container'
+        # Simulate success, then failure, then success
+        mock_redis.incr.side_effect = [
+            1,
+            RedisError('Temporary failure'),
+            2
+        ]
+
+        # Act & Assert
+        response1 = self.client.get('/')
+        self.assertEqual(response1.status_code, 200)
+        self.assertIn(b'1', response1.data)
+
+        response2 = self.client.get('/')
+        self.assertEqual(response2.status_code, 200)
+        self.assertIn(b'cannot connect to Redis', response2.data)
+
+        response3 = self.client.get('/')
+        self.assertEqual(response3.status_code, 200)
+        self.assertIn(b'2', response3.data)
+
+
+if __name__ == '__main__':
+    unittest.main()

2-building-images/Dockerfile.test

@@ -0,0 +1,14 @@
+# Dockerfile for running tests
+FROM python:3.9-slim
+
+WORKDIR /app
+
+# Copy requirements and install dependencies
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy application code and tests
+COPY . .
+
+# Run tests by default
+CMD ["python", "-m", "pytest", "-v", "test_app.py"]

2-building-images/requirements.txt

@@ -1,2 +1,5 @@
 Flask
-Redis
+Redis
+pytest>=7.4.0
+pytest-flask>=1.2.0
+pytest-mock>=3.11.0