diff --git a/Documentation/TESTING.md b/Documentation/TESTING.md
new file mode 100644
index 0000000..1254aea
--- /dev/null
+++ b/Documentation/TESTING.md
@@ -0,0 +1,259 @@
+# Running Tests
+
+This document describes how to run the test suite for the vgui-cicd project.
+
+## Test Structure
+
+The project includes comprehensive unit tests for the diagram caching functionality:
+
+```
+abschnitte/
+├── tests.py                              # Tests for rendering functions
+├── management/
+│   └── commands/
+│       └── test_clear_diagram_cache.py  # Tests for management command
+
+diagramm_proxy/
+└── test_diagram_cache.py                # Tests for caching module
+```
+
+## Running All Tests
+
+To run the entire test suite:
+
+```bash
+python manage.py test
+```
+
+## Running Specific Test Modules
+
+Run tests for a specific app:
+
+```bash
+# Test abschnitte rendering
+python manage.py test abschnitte
+
+# Test diagram caching
+python manage.py test diagramm_proxy
+
+# Test management commands
+python manage.py test abschnitte.management.commands
+```
+
+## Running Individual Test Cases
+
+Run a specific test case:
+
+```bash
+# Test diagram cache functionality
+python manage.py test diagramm_proxy.test_diagram_cache.DiagramCacheTestCase
+
+# Test rendering functions
+python manage.py test abschnitte.tests.RenderTextabschnitteTestCase
+
+# Test management command
+python manage.py test abschnitte.management.commands.test_clear_diagram_cache
+```
+
+## Running Individual Tests
+
+Run a single test method:
+
+```bash
+python manage.py test abschnitte.tests.RenderTextabschnitteTestCase.test_render_diagram_success
+```
+
+## Test Coverage
+
+To generate a coverage report, install coverage.py:
+
+```bash
+pip install coverage
+```
+
+Then run:
+
+```bash
+# Run tests with coverage
+coverage run --source='.' manage.py test
+
+# Generate coverage report
+coverage report
+
+# Generate HTML coverage report
+coverage html
+# Open htmlcov/index.html in browser
+```
+
+## Test Options
+
+### Verbose Output
+
+Get more detailed output:
+
+```bash
+python manage.py test --verbosity=2
+```
+
+### Keep Test Database
+
+Keep the test database after tests complete (useful for debugging):
+
+```bash
+python manage.py test --keepdb
+```
+
+### Fail Fast
+
+Stop after first test failure:
+
+```bash
+python manage.py test --failfast
+```
+
+### Parallel Testing
+
+Run tests in parallel (faster for large test suites):
+
+```bash
+python manage.py test --parallel
+```
+
+## What the Tests Cover
+
+### Diagram Caching Tests (`diagramm_proxy/test_diagram_cache.py`)
+
+- ✅ Hash computation and consistency
+- ✅ Cache path generation
+- ✅ Cache miss (diagram generation)
+- ✅ Cache hit (using cached diagrams)
+- ✅ HTTP error handling
+- ✅ Cache clearing (all and by type)
+- ✅ Unicode content handling
+- ✅ Timeout configuration
+- ✅ Full lifecycle integration tests
+
+### Rendering Tests (`abschnitte/tests.py`)
+
+- ✅ Text rendering with markdown
+- ✅ Unordered and ordered lists
+- ✅ Table rendering
+- ✅ Diagram rendering (success and error)
+- ✅ Diagram with custom options
+- ✅ Code blocks
+- ✅ Edge cases (empty content, missing types)
+- ✅ Multiple sections
+- ✅ Mixed content integration tests
+
+### Management Command Tests (`abschnitte/management/commands/test_clear_diagram_cache.py`)
+
+- ✅ Clearing all cache
+- ✅ Clearing by specific type
+- ✅ Clearing empty cache
+- ✅ Command help text
+- ✅ Full workflow integration
+
+## Continuous Integration
+
+These tests are designed to run in CI/CD pipelines. Example GitHub Actions workflow:
+
+```yaml
+name: Tests
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.11
+      - name: Install dependencies
+        run: |
+          pip install -r requirements.txt
+      - name: Run tests
+        run: |
+          python manage.py test --verbosity=2
+```
+
+## Debugging Failed Tests
+
+If tests fail, you can:
+
+1. **Run with verbose output** to see detailed error messages:
+   ```bash
+   python manage.py test --verbosity=2
+   ```
+
+2. **Run specific failing test** to isolate the issue:
+   ```bash
+   python manage.py test path.to.TestCase.test_method
+   ```
+
+3. **Use pdb for debugging**:
+   ```python
+   import pdb; pdb.set_trace()  # Add to test code
+   ```
+
+4. **Check test database**:
+   ```bash
+   python manage.py test --keepdb
+   ```
+
+## Test Requirements
+
+The tests use:
+- Django's built-in `TestCase` class
+- Python's `unittest.mock` for mocking external dependencies
+- `@override_settings` for temporary setting changes
+- `tempfile` for creating temporary directories
+
+No additional testing libraries are required beyond what's in `requirements.txt`.
+
+## Writing New Tests
+
+When adding new features, follow these patterns:
+
+1. **Test file location**: Place tests in the same app as the code being tested
+2. **Test class naming**: Use descriptive names ending in `TestCase`
+3. **Test method naming**: Start with `test_` and describe what's being tested
+4. **Use mocks**: Mock external dependencies (HTTP calls, file systems when needed)
+5. **Clean up**: Use `setUp()` and `tearDown()` or temporary directories
+6. **Test edge cases**: Include tests for error conditions and edge cases
+
+Example:
+
+```python
+from django.test import TestCase
+from unittest.mock import patch
+
+class MyFeatureTestCase(TestCase):
+    def setUp(self):
+        """Set up test fixtures."""
+        self.test_data = "example"
+    
+    def test_basic_functionality(self):
+        """Test that the feature works correctly."""
+        result = my_function(self.test_data)
+        self.assertEqual(result, expected_value)
+    
+    @patch('my_app.module.external_call')
+    def test_with_mock(self, mock_call):
+        """Test with mocked external dependency."""
+        mock_call.return_value = "mocked"
+        result = my_function(self.test_data)
+        mock_call.assert_called_once()
+```
+
+## Test Best Practices
+
+- Write tests before or alongside code (TDD approach)
+- Each test should test one thing
+- Tests should be independent (no shared state)
+- Use descriptive test names
+- Mock external dependencies (HTTP, filesystem, etc.)
+- Test both success and failure cases
+- Aim for high code coverage (>80%)
diff --git a/TESTING_QUICKSTART.md b/TESTING_QUICKSTART.md
new file mode 100644
index 0000000..d09802f
--- /dev/null
+++ b/TESTING_QUICKSTART.md
@@ -0,0 +1,99 @@
+# Quick Test Guide
+
+Quick reference for running tests in the vgui-cicd project.
+
+## 🚀 Quick Start
+
+```bash
+# Run all tests
+python manage.py test
+
+# Or use the convenient runner
+python run_tests.py all
+```
+
+## 📋 Common Commands
+
+| Command | Description |
+|---------|-------------|
+| `python run_tests.py all` | Run all tests with verbose output |
+| `python run_tests.py cache` | Run diagram cache tests only |
+| `python run_tests.py render` | Run rendering tests only |
+| `python run_tests.py commands` | Run management command tests |
+| `python run_tests.py coverage` | Run tests with coverage report |
+| `python run_tests.py fast` | Run with fail-fast (stops at first failure) |
+
+## 🎯 Run Specific Tests
+
+```bash
+# Test a specific module
+python manage.py test diagramm_proxy
+
+# Test a specific test case
+python manage.py test abschnitte.tests.RenderTextabschnitteTestCase
+
+# Test a specific method
+python manage.py test abschnitte.tests.RenderTextabschnitteTestCase.test_render_diagram_success
+```
+
+## 📊 Coverage Report
+
+```bash
+# Generate coverage report
+python run_tests.py coverage
+
+# Or manually
+pip install coverage
+coverage run --source='.' manage.py test
+coverage report
+coverage html  # Creates htmlcov/index.html
+```
+
+## ✅ What's Tested
+
+### Diagram Caching (`diagramm_proxy/test_diagram_cache.py`)
+- Hash computation ✓
+- Cache hit/miss ✓
+- HTTP errors ✓
+- Cache clearing ✓
+- Unicode support ✓
+
+### Rendering (`abschnitte/tests.py`)
+- Markdown to HTML ✓
+- Lists (ordered/unordered) ✓
+- Tables ✓
+- Diagrams ✓
+- Code blocks ✓
+
+### Management Commands (`abschnitte/management/commands/test_clear_diagram_cache.py`)
+- Clear all cache ✓
+- Clear by type ✓
+- Help text ✓
+
+## 🐛 Debugging Failed Tests
+
+```bash
+# Run with more detail
+python manage.py test --verbosity=2
+
+# Stop at first failure
+python manage.py test --failfast
+
+# Keep test database
+python manage.py test --keepdb
+```
+
+## 📖 More Information
+
+See `Documentation/TESTING.md` for complete documentation.
+
+## 🎓 Test Statistics
+
+- **Total Test Files**: 3
+- **Total Test Cases**: 29+
+- **Lines of Test Code**: 790+
+- **Coverage Target**: >80%
+
+---
+
+**Need help?** Check the full testing guide in `Documentation/TESTING.md`
diff --git a/abschnitte/management/commands/test_clear_diagram_cache.py b/abschnitte/management/commands/test_clear_diagram_cache.py
new file mode 100644
index 0000000..4b1347b
--- /dev/null
+++ b/abschnitte/management/commands/test_clear_diagram_cache.py
@@ -0,0 +1,164 @@
+import os
+import tempfile
+from io import StringIO
+from unittest.mock import patch, Mock
+from django.test import TestCase, override_settings
+from django.core.management import call_command
+from django.core.files.storage import default_storage
+from django.core.files.base import ContentFile
+
+
+class ClearDiagramCacheCommandTestCase(TestCase):
+    """Test cases for clear_diagram_cache management command."""
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    def test_clear_all_cache(self):
+        """Test clearing all cached diagrams."""
+        # Create test cache files
+        test_files = [
+            'diagram_cache/plantuml/hash1.svg',
+            'diagram_cache/plantuml/hash2.svg',
+            'diagram_cache/mermaid/hash3.svg',
+        ]
+        
+        for path in test_files:
+            full_path = default_storage.path(path)
+            os.makedirs(os.path.dirname(full_path), exist_ok=True)
+            default_storage.save(path, ContentFile(b'test diagram'))
+        
+        # Verify files exist
+        for path in test_files:
+            self.assertTrue(default_storage.exists(path))
+        
+        # Run command
+        out = StringIO()
+        call_command('clear_diagram_cache', stdout=out)
+        
+        # Verify files are deleted
+        for path in test_files:
+            self.assertFalse(default_storage.exists(path))
+        
+        # Verify success message
+        output = out.getvalue()
+        self.assertIn('Clearing all diagram caches', output)
+        self.assertIn('Cache cleared successfully', output)
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    def test_clear_cache_by_type(self):
+        """Test clearing cache for specific diagram type."""
+        # Create test cache files
+        plantuml_files = [
+            'diagram_cache/plantuml/hash1.svg',
+            'diagram_cache/plantuml/hash2.svg',
+        ]
+        mermaid_files = [
+            'diagram_cache/mermaid/hash3.svg',
+        ]
+        
+        for path in plantuml_files + mermaid_files:
+            full_path = default_storage.path(path)
+            os.makedirs(os.path.dirname(full_path), exist_ok=True)
+            default_storage.save(path, ContentFile(b'test diagram'))
+        
+        # Run command for plantuml only
+        out = StringIO()
+        call_command('clear_diagram_cache', type='plantuml', stdout=out)
+        
+        # Verify only plantuml files are deleted
+        for path in plantuml_files:
+            self.assertFalse(default_storage.exists(path))
+        
+        for path in mermaid_files:
+            self.assertTrue(default_storage.exists(path))
+        
+        # Verify output message
+        output = out.getvalue()
+        self.assertIn('Clearing cache for plantuml', output)
+        self.assertIn('Cache cleared successfully', output)
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    def test_clear_empty_cache(self):
+        """Test clearing cache when no files exist."""
+        # Don't create any files
+        
+        # Should not raise error
+        out = StringIO()
+        call_command('clear_diagram_cache', stdout=out)
+        
+        # Should still show success
+        output = out.getvalue()
+        self.assertIn('Cache cleared successfully', output)
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    @patch('diagramm_proxy.diagram_cache.clear_cache')
+    def test_command_calls_clear_cache_function(self, mock_clear):
+        """Test that command properly calls the clear_cache function."""
+        # Call without type
+        call_command('clear_diagram_cache')
+        mock_clear.assert_called_once_with(None)
+        
+        # Call with type
+        mock_clear.reset_mock()
+        call_command('clear_diagram_cache', type='plantuml')
+        mock_clear.assert_called_once_with('plantuml')
+    
+    def test_command_help_text(self):
+        """Test that command has proper help text."""
+        out = StringIO()
+        call_command('clear_diagram_cache', '--help', stdout=out)
+        output = out.getvalue()
+        
+        self.assertIn('Clear cached diagrams', output)
+        self.assertIn('--type', output)
+
+
+class ManagementCommandIntegrationTestCase(TestCase):
+    """Integration tests for management command with real filesystem."""
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    def test_full_command_workflow(self):
+        """Test complete workflow: create cache, clear specific type, clear all."""
+        # Create mixed cache files
+        files = {
+            'plantuml': [
+                'diagram_cache/plantuml/abc123.svg',
+                'diagram_cache/plantuml/def456.svg',
+            ],
+            'mermaid': [
+                'diagram_cache/mermaid/ghi789.svg',
+            ],
+            'graphviz': [
+                'diagram_cache/graphviz/jkl012.svg',
+            ]
+        }
+        
+        # Create all files
+        for file_list in files.values():
+            for path in file_list:
+                full_path = default_storage.path(path)
+                os.makedirs(os.path.dirname(full_path), exist_ok=True)
+                default_storage.save(path, ContentFile(b'diagram content'))
+        
+        # Verify all exist
+        for file_list in files.values():
+            for path in file_list:
+                self.assertTrue(default_storage.exists(path))
+        
+        # Clear plantuml
+        call_command('clear_diagram_cache', type='plantuml')
+        
+        # Verify plantuml deleted, others remain
+        for path in files['plantuml']:
+            self.assertFalse(default_storage.exists(path))
+        for path in files['mermaid']:
+            self.assertTrue(default_storage.exists(path))
+        for path in files['graphviz']:
+            self.assertTrue(default_storage.exists(path))
+        
+        # Clear all remaining
+        call_command('clear_diagram_cache')
+        
+        # Verify all deleted
+        for file_list in files.values():
+            for path in file_list:
+                self.assertFalse(default_storage.exists(path))
diff --git a/abschnitte/tests.py b/abschnitte/tests.py
index 7ce503c..93a0813 100644
--- a/abschnitte/tests.py
+++ b/abschnitte/tests.py
@@ -1,3 +1,377 @@
-from django.test import TestCase
+from unittest.mock import Mock, patch, MagicMock
+from django.test import TestCase, override_settings
+from abschnitte.models import AbschnittTyp, Textabschnitt
+from abschnitte.utils import render_textabschnitte, md_table_to_html
 
-# Create your tests here.
+
+class MockTextabschnitt:
+    """Mock object for Textabschnitt (since it's abstract)."""
+    def __init__(self, abschnitttyp, inhalt):
+        self.abschnitttyp = abschnitttyp
+        self.inhalt = inhalt
+
+
+class RenderTextabschnitteTestCase(TestCase):
+    """Test cases for render_textabschnitte function."""
+    
+    def setUp(self):
+        """Set up test fixtures."""
+        # Create mock AbschnittTyp objects
+        self.typ_text = Mock()
+        self.typ_text.abschnitttyp = "text"
+        
+        self.typ_liste_ungeordnet = Mock()
+        self.typ_liste_ungeordnet.abschnitttyp = "liste ungeordnet"
+        
+        self.typ_liste_geordnet = Mock()
+        self.typ_liste_geordnet.abschnitttyp = "liste geordnet"
+        
+        self.typ_tabelle = Mock()
+        self.typ_tabelle.abschnitttyp = "tabelle"
+        
+        self.typ_diagramm = Mock()
+        self.typ_diagramm.abschnitttyp = "diagramm"
+        
+        self.typ_code = Mock()
+        self.typ_code.abschnitttyp = "code"
+    
+    def test_render_basic_text(self):
+        """Test rendering basic text content."""
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_text,
+            inhalt="This is **bold** text with *italic*."
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        self.assertEqual(len(result), 1)
+        typ, html = result[0]
+        self.assertEqual(typ, "text")
+        self.assertIn("<strong>bold</strong>", html)
+        self.assertIn("<em>italic</em>", html)
+    
+    def test_render_unordered_list(self):
+        """Test rendering unordered list."""
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_liste_ungeordnet,
+            inhalt="Item 1\nItem 2\nItem 3"
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        self.assertEqual(len(result), 1)
+        typ, html = result[0]
+        self.assertEqual(typ, "liste ungeordnet")
+        self.assertIn("<ul>", html)
+        self.assertIn("<li>Item 1</li>", html)
+        self.assertIn("<li>Item 2</li>", html)
+        self.assertIn("<li>Item 3</li>", html)
+    
+    def test_render_ordered_list(self):
+        """Test rendering ordered list."""
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_liste_geordnet,
+            inhalt="First item\nSecond item\nThird item"
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        self.assertEqual(len(result), 1)
+        typ, html = result[0]
+        self.assertEqual(typ, "liste geordnet")
+        self.assertIn("<ol>", html)
+        self.assertIn("<li>First item</li>", html)
+    
+    def test_render_table(self):
+        """Test rendering markdown table."""
+        table_content = """| Header 1 | Header 2 |
+|----------|----------|
+| Cell 1   | Cell 2   |
+| Cell 3   | Cell 4   |"""
+        
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_tabelle,
+            inhalt=table_content
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        self.assertEqual(len(result), 1)
+        typ, html = result[0]
+        self.assertEqual(typ, "tabelle")
+        self.assertIn("<table", html)
+        self.assertIn("Header 1", html)
+        self.assertIn("Cell 1", html)
+        self.assertIn("table-bordered", html)
+    
+    @override_settings(MEDIA_URL='/media/')
+    @patch('abschnitte.utils.get_cached_diagram')
+    def test_render_diagram_success(self, mock_get_cached):
+        """Test rendering diagram with successful cache."""
+        mock_get_cached.return_value = 'diagram_cache/plantuml/abc123.svg'
+        
+        diagram_content = """plantuml
+@startuml
+A -> B
+@enduml"""
+        
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_diagramm,
+            inhalt=diagram_content
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        self.assertEqual(len(result), 1)
+        typ, html = result[0]
+        self.assertEqual(typ, "diagramm")
+        
+        # Verify diagram cache was called correctly
+        mock_get_cached.assert_called_once_with(
+            'plantuml',
+            '@startuml\nA -> B\n@enduml'
+        )
+        
+        # Verify HTML contains correct image tag
+        self.assertIn('<img', html)
+        self.assertIn('/media/diagram_cache/plantuml/abc123.svg', html)
+        self.assertIn('width="100%"', html)
+    
+    @patch('abschnitte.utils.get_cached_diagram')
+    def test_render_diagram_with_options(self, mock_get_cached):
+        """Test rendering diagram with custom options."""
+        mock_get_cached.return_value = 'diagram_cache/mermaid/def456.svg'
+        
+        diagram_content = """mermaid
+option:width="50%" height="300px"
+graph TD
+A --> B"""
+        
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_diagramm,
+            inhalt=diagram_content
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        typ, html = result[0]
+        
+        # Verify custom options are used
+        self.assertIn('width="50%"', html)
+        self.assertIn('height="300px"', html)
+        
+        # Verify diagram content doesn't include option line
+        call_args = mock_get_cached.call_args[0]
+        self.assertNotIn('option:', call_args[1])
+    
+    @patch('abschnitte.utils.get_cached_diagram')
+    def test_render_diagram_error(self, mock_get_cached):
+        """Test rendering diagram when caching fails."""
+        mock_get_cached.side_effect = Exception("Kroki server unavailable")
+        
+        diagram_content = """plantuml
+@startuml
+A -> B
+@enduml"""
+        
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_diagramm,
+            inhalt=diagram_content
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        typ, html = result[0]
+        
+        # Should show error message
+        self.assertIn('Error generating diagram', html)
+        self.assertIn('Kroki server unavailable', html)
+        self.assertIn('text-danger', html)
+    
+    def test_render_code(self):
+        """Test rendering code block."""
+        code_content = """def hello():
+    print("Hello, World!")"""
+        
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_code,
+            inhalt=code_content
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        typ, html = result[0]
+        self.assertEqual(typ, "code")
+        self.assertIn("<pre>", html)
+        self.assertIn("<code>", html)
+        self.assertIn("def hello():", html)
+    
+    def test_render_empty_content(self):
+        """Test rendering with empty or None content."""
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=self.typ_text,
+            inhalt=None
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        self.assertEqual(len(result), 1)
+        typ, html = result[0]
+        self.assertEqual(typ, "text")
+        # Should not crash, should return empty or minimal HTML
+    
+    def test_render_multiple_abschnitte(self):
+        """Test rendering multiple sections."""
+        abschnitte = [
+            MockTextabschnitt(self.typ_text, "First paragraph"),
+            MockTextabschnitt(self.typ_liste_ungeordnet, "Item 1\nItem 2"),
+            MockTextabschnitt(self.typ_text, "Second paragraph"),
+        ]
+        
+        result = render_textabschnitte(abschnitte)
+        
+        self.assertEqual(len(result), 3)
+        self.assertEqual(result[0][0], "text")
+        self.assertEqual(result[1][0], "liste ungeordnet")
+        self.assertEqual(result[2][0], "text")
+    
+    def test_render_no_abschnitttyp(self):
+        """Test rendering when abschnitttyp is None."""
+        abschnitt = MockTextabschnitt(
+            abschnitttyp=None,
+            inhalt="Some content"
+        )
+        
+        result = render_textabschnitte([abschnitt])
+        
+        self.assertEqual(len(result), 1)
+        typ, html = result[0]
+        self.assertEqual(typ, "")
+        # Should still render as markdown
+        self.assertIn("Some content", html)
+
+
+class MdTableToHtmlTestCase(TestCase):
+    """Test cases for md_table_to_html function."""
+    
+    def test_basic_table(self):
+        """Test converting basic markdown table to HTML."""
+        md = """| Name | Age |
+|------|-----|
+| Alice | 30 |
+| Bob | 25 |"""
+        
+        html = md_table_to_html(md)
+        
+        self.assertIn('<table', html)
+        self.assertIn('table-bordered', html)
+        self.assertIn('table-hover', html)
+        self.assertIn('<thead>', html)
+        self.assertIn('<tbody>', html)
+        self.assertIn('<th>Name</th>', html)
+        self.assertIn('<th>Age</th>', html)
+        self.assertIn('<td>Alice</td>', html)
+        self.assertIn('<td>30</td>', html)
+    
+    def test_table_with_spaces(self):
+        """Test table with various spacing."""
+        md = """|  Name  |  Age  |
+|--------|-------|
+|  Alice |   30  |
+|   Bob  |  25   |"""
+        
+        html = md_table_to_html(md)
+        
+        # Spaces should be trimmed
+        self.assertIn('<th>Name</th>', html)
+        self.assertIn('<th>Age</th>', html)
+        self.assertIn('<td>Alice</td>', html)
+    
+    def test_table_no_outer_pipes(self):
+        """Test table without outer pipe characters."""
+        md = """Name | Age
+-----|-----
+Alice | 30
+Bob | 25"""
+        
+        html = md_table_to_html(md)
+        
+        self.assertIn('<th>Name</th>', html)
+        self.assertIn('<td>Alice</td>', html)
+    
+    def test_table_insufficient_rows(self):
+        """Test error handling for malformed table."""
+        md = """| Name |
+|------|"""
+        
+        with self.assertRaises(ValueError) as context:
+            md_table_to_html(md)
+        
+        self.assertIn("at least header + separator", str(context.exception))
+    
+    def test_table_with_empty_cells(self):
+        """Test table with empty cells."""
+        md = """| Name | Age |
+|------|-----|
+| Alice |  |
+|  | 25 |"""
+        
+        html = md_table_to_html(md)
+        
+        self.assertIn('<td>Alice</td>', html)
+        self.assertIn('<td></td>', html)
+        self.assertIn('<td>25</td>', html)
+    
+    def test_table_three_columns(self):
+        """Test table with more columns."""
+        md = """| First | Middle | Last |
+|-------|--------|------|
+| John  | Q      | Doe  |"""
+        
+        html = md_table_to_html(md)
+        
+        self.assertIn('<th>First</th>', html)
+        self.assertIn('<th>Middle</th>', html)
+        self.assertIn('<th>Last</th>', html)
+        self.assertIn('<td>John</td>', html)
+        self.assertIn('<td>Q</td>', html)
+        self.assertIn('<td>Doe</td>', html)
+
+
+class RenderIntegrationTestCase(TestCase):
+    """Integration tests for rendering pipeline."""
+    
+    @patch('abschnitte.utils.get_cached_diagram')
+    def test_mixed_content_rendering(self, mock_get_cached):
+        """Test rendering a mix of different content types."""
+        mock_get_cached.return_value = 'diagram_cache/test.svg'
+        
+        # Create various types of content
+        typ_text = Mock(abschnitttyp="text")
+        typ_liste = Mock(abschnitttyp="liste ungeordnet")
+        typ_diagram = Mock(abschnitttyp="diagramm")
+        
+        abschnitte = [
+            MockTextabschnitt(typ_text, "Introduction paragraph"),
+            MockTextabschnitt(typ_liste, "Point 1\nPoint 2\nPoint 3"),
+            MockTextabschnitt(typ_diagram, "plantuml\n@startuml\nA -> B\n@enduml"),
+            MockTextabschnitt(typ_text, "Conclusion"),
+        ]
+        
+        result = render_textabschnitte(abschnitte)
+        
+        # Should have 4 results
+        self.assertEqual(len(result), 4)
+        
+        # Verify each type was rendered correctly
+        self.assertEqual(result[0][0], "text")
+        self.assertIn("Introduction", result[0][1])
+        
+        self.assertEqual(result[1][0], "liste ungeordnet")
+        self.assertIn("<ul>", result[1][1])
+        
+        self.assertEqual(result[2][0], "diagramm")
+        self.assertIn("<img", result[2][1])
+        
+        self.assertEqual(result[3][0], "text")
+        self.assertIn("Conclusion", result[3][1])
diff --git a/diagramm_proxy/test_diagram_cache.py b/diagramm_proxy/test_diagram_cache.py
new file mode 100644
index 0000000..eed7f42
--- /dev/null
+++ b/diagramm_proxy/test_diagram_cache.py
@@ -0,0 +1,267 @@
+import os
+import hashlib
+import tempfile
+from unittest.mock import patch, Mock, MagicMock
+from django.test import TestCase, override_settings
+from django.core.files.storage import default_storage
+from django.core.files.base import ContentFile
+from diagramm_proxy.diagram_cache import (
+    get_cache_path,
+    compute_hash,
+    get_cached_diagram,
+    clear_cache,
+    KROKI_UPSTREAM
+)
+
+
+class DiagramCacheTestCase(TestCase):
+    """Test cases for diagram caching functionality."""
+    
+    def setUp(self):
+        """Set up test fixtures."""
+        self.test_diagram_content = """
+        @startuml
+        Alice -> Bob: Hello
+        Bob -> Alice: Hi
+        @enduml
+        """
+        self.diagram_type = "plantuml"
+        self.temp_media_root = tempfile.mkdtemp()
+    
+    def tearDown(self):
+        """Clean up after tests."""
+        # Clean up temporary files
+        import shutil
+        if os.path.exists(self.temp_media_root):
+            shutil.rmtree(self.temp_media_root)
+    
+    def test_compute_hash(self):
+        """Test that hash computation is consistent."""
+        content1 = "test content"
+        content2 = "test content"
+        content3 = "different content"
+        
+        hash1 = compute_hash(content1)
+        hash2 = compute_hash(content2)
+        hash3 = compute_hash(content3)
+        
+        # Same content should produce same hash
+        self.assertEqual(hash1, hash2)
+        
+        # Different content should produce different hash
+        self.assertNotEqual(hash1, hash3)
+        
+        # Hash should be valid SHA256 (64 hex characters)
+        self.assertEqual(len(hash1), 64)
+        self.assertTrue(all(c in '0123456789abcdef' for c in hash1))
+    
+    def test_get_cache_path(self):
+        """Test cache path generation."""
+        content_hash = "abc123def456"
+        diagram_type = "mermaid"
+        
+        path = get_cache_path(diagram_type, content_hash)
+        
+        # Path should contain diagram type and hash
+        self.assertIn("diagram_cache", path)
+        self.assertIn(diagram_type, path)
+        self.assertIn(content_hash, path)
+        self.assertTrue(path.endswith(".svg"))
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    @patch('diagramm_proxy.diagram_cache.requests.post')
+    def test_get_cached_diagram_cache_miss(self, mock_post):
+        """Test diagram generation on cache miss."""
+        # Mock successful Kroki response
+        mock_response = Mock()
+        mock_response.status_code = 200
+        mock_response.content = b'<svg>test diagram</svg>'
+        mock_response.raise_for_status = Mock()
+        mock_post.return_value = mock_response
+        
+        # Call function
+        result = get_cached_diagram(self.diagram_type, self.test_diagram_content)
+        
+        # Verify POST was called with correct parameters
+        expected_url = f"{KROKI_UPSTREAM}/{self.diagram_type}/svg"
+        mock_post.assert_called_once()
+        call_args = mock_post.call_args
+        self.assertEqual(call_args[0][0], expected_url)
+        self.assertEqual(call_args[1]['data'], self.test_diagram_content.encode('utf-8'))
+        self.assertEqual(call_args[1]['headers']['Content-Type'], 'text/plain')
+        
+        # Verify result is a valid path
+        self.assertIsNotNone(result)
+        self.assertIn('diagram_cache', result)
+        
+        # Verify file was cached
+        self.assertTrue(default_storage.exists(result))
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    def test_get_cached_diagram_cache_hit(self):
+        """Test that cached diagrams are retrieved without HTTP call."""
+        # Pre-populate cache
+        content_hash = compute_hash(self.test_diagram_content)
+        cache_path = get_cache_path(self.diagram_type, content_hash)
+        
+        # Create cache directory and file
+        full_path = default_storage.path(cache_path)
+        os.makedirs(os.path.dirname(full_path), exist_ok=True)
+        default_storage.save(cache_path, ContentFile(b'<svg>cached diagram</svg>'))
+        
+        # Mock requests.post to ensure it's NOT called
+        with patch('diagramm_proxy.diagram_cache.requests.post') as mock_post:
+            result = get_cached_diagram(self.diagram_type, self.test_diagram_content)
+            
+            # Verify POST was NOT called (cache hit)
+            mock_post.assert_not_called()
+            
+            # Verify correct path returned
+            self.assertEqual(result, cache_path)
+            
+            # Verify file exists
+            self.assertTrue(default_storage.exists(result))
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    @patch('diagramm_proxy.diagram_cache.requests.post')
+    def test_get_cached_diagram_http_error(self, mock_post):
+        """Test error handling when Kroki server fails."""
+        # Mock failed HTTP response
+        mock_post.side_effect = Exception("Connection failed")
+        
+        # Should raise exception
+        with self.assertRaises(Exception):
+            get_cached_diagram(self.diagram_type, self.test_diagram_content)
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    def test_clear_cache_all(self):
+        """Test clearing all cached diagrams."""
+        # Create some test cache files
+        test_files = [
+            ('diagram_cache/plantuml/hash1.svg', b'diagram1'),
+            ('diagram_cache/plantuml/hash2.svg', b'diagram2'),
+            ('diagram_cache/mermaid/hash3.svg', b'diagram3'),
+        ]
+        
+        for path, content in test_files:
+            full_path = default_storage.path(path)
+            os.makedirs(os.path.dirname(full_path), exist_ok=True)
+            default_storage.save(path, ContentFile(content))
+        
+        # Verify files exist
+        for path, _ in test_files:
+            self.assertTrue(default_storage.exists(path))
+        
+        # Clear all cache
+        clear_cache()
+        
+        # Verify files are deleted
+        for path, _ in test_files:
+            self.assertFalse(default_storage.exists(path))
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    def test_clear_cache_by_type(self):
+        """Test clearing cache for specific diagram type."""
+        # Create test cache files
+        plantuml_file = 'diagram_cache/plantuml/hash1.svg'
+        mermaid_file = 'diagram_cache/mermaid/hash2.svg'
+        
+        for path in [plantuml_file, mermaid_file]:
+            full_path = default_storage.path(path)
+            os.makedirs(os.path.dirname(full_path), exist_ok=True)
+            default_storage.save(path, ContentFile(b'test'))
+        
+        # Clear only plantuml cache
+        clear_cache('plantuml')
+        
+        # Verify plantuml file is deleted but mermaid remains
+        self.assertFalse(default_storage.exists(plantuml_file))
+        self.assertTrue(default_storage.exists(mermaid_file))
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    @patch('diagramm_proxy.diagram_cache.requests.post')
+    def test_same_content_different_type(self, mock_post):
+        """Test that same content but different type creates different cache entries."""
+        mock_response = Mock()
+        mock_response.status_code = 200
+        mock_response.content = b'<svg>diagram</svg>'
+        mock_response.raise_for_status = Mock()
+        mock_post.return_value = mock_response
+        
+        # Generate for two different types
+        path1 = get_cached_diagram('plantuml', self.test_diagram_content)
+        path2 = get_cached_diagram('mermaid', self.test_diagram_content)
+        
+        # Paths should be different
+        self.assertNotEqual(path1, path2)
+        self.assertIn('plantuml', path1)
+        self.assertIn('mermaid', path2)
+        
+        # Both should exist
+        self.assertTrue(default_storage.exists(path1))
+        self.assertTrue(default_storage.exists(path2))
+    
+    def test_compute_hash_unicode(self):
+        """Test hash computation with unicode characters."""
+        content_with_unicode = "Test with émojis 🎨 and ümlauts"
+        
+        # Should not raise exception
+        result = compute_hash(content_with_unicode)
+        
+        # Should produce valid hash
+        self.assertEqual(len(result), 64)
+        self.assertTrue(all(c in '0123456789abcdef' for c in result))
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    @patch('diagramm_proxy.diagram_cache.requests.post')
+    def test_timeout_configuration(self, mock_post):
+        """Test that POST request includes timeout."""
+        mock_response = Mock()
+        mock_response.status_code = 200
+        mock_response.content = b'<svg>test</svg>'
+        mock_response.raise_for_status = Mock()
+        mock_post.return_value = mock_response
+        
+        get_cached_diagram(self.diagram_type, self.test_diagram_content)
+        
+        # Verify timeout parameter was passed
+        call_kwargs = mock_post.call_args[1]
+        self.assertIn('timeout', call_kwargs)
+        self.assertEqual(call_kwargs['timeout'], 30)
+
+
+class DiagramCacheIntegrationTestCase(TestCase):
+    """Integration tests for diagram caching with file system."""
+    
+    @override_settings(MEDIA_ROOT=tempfile.mkdtemp())
+    @patch('diagramm_proxy.diagram_cache.requests.post')
+    def test_full_cache_lifecycle(self, mock_post):
+        """Test complete lifecycle: cache miss, cache hit, clear."""
+        diagram_content = "@startuml\nA -> B\n@enduml"
+        diagram_type = "plantuml"
+        
+        # Mock Kroki response
+        mock_response = Mock()
+        mock_response.status_code = 200
+        mock_response.content = b'<svg>lifecycle test</svg>'
+        mock_response.raise_for_status = Mock()
+        mock_post.return_value = mock_response
+        
+        # First call - cache miss
+        path1 = get_cached_diagram(diagram_type, diagram_content)
+        self.assertEqual(mock_post.call_count, 1)
+        self.assertTrue(default_storage.exists(path1))
+        
+        # Second call - cache hit
+        path2 = get_cached_diagram(diagram_type, diagram_content)
+        self.assertEqual(mock_post.call_count, 1)  # Still 1, not called again
+        self.assertEqual(path1, path2)
+        
+        # Clear cache
+        clear_cache()
+        self.assertFalse(default_storage.exists(path1))
+        
+        # Third call - cache miss again
+        path3 = get_cached_diagram(diagram_type, diagram_content)
+        self.assertEqual(mock_post.call_count, 2)  # Called again
+        self.assertTrue(default_storage.exists(path3))
diff --git a/pytest.ini b/pytest.ini
new file mode 100644
index 0000000..0396ddf
--- /dev/null
+++ b/pytest.ini
@@ -0,0 +1,60 @@
+[tool:pytest]
+# Pytest configuration for vgui-cicd project
+# To use pytest instead of Django's test runner:
+#   pip install pytest pytest-django
+#   pytest
+
+DJANGO_SETTINGS_MODULE = VorgabenUI.settings
+python_files = tests.py test_*.py *_tests.py
+python_classes = *TestCase *Test
+python_functions = test_*
+
+# Test discovery patterns
+testpaths = 
+    abschnitte
+    diagramm_proxy
+    standards
+    stichworte
+    referenzen
+    rollen
+    pages
+
+# Output options
+addopts = 
+    --verbose
+    --strict-markers
+    --tb=short
+    --reuse-db
+    
+# Coverage options (when using pytest-cov)
+# Uncomment to enable:
+# --cov=.
+# --cov-report=html
+# --cov-report=term-missing
+
+# Markers for organizing tests
+markers =
+    slow: marks tests as slow (deselect with '-m "not slow"')
+    integration: marks tests as integration tests
+    unit: marks tests as unit tests
+    cache: marks tests related to caching
+    render: marks tests related to rendering
+    commands: marks tests related to management commands
+
+# Ignore paths
+norecursedirs = 
+    .git
+    .tox
+    dist
+    build
+    *.egg
+    __pycache__
+    static
+    staticfiles
+    media
+    data
+    venv
+    .venv
+
+# Django-specific settings
+django_find_project = false
diff --git a/run_tests.py b/run_tests.py
new file mode 100644
index 0000000..2157c54
--- /dev/null
+++ b/run_tests.py
@@ -0,0 +1,108 @@
+#!/usr/bin/env python
+"""
+Test runner script for vgui-cicd project.
+Provides convenient shortcuts for running different test suites.
+"""
+
+import sys
+import os
+from django.core.management import execute_from_command_line
+
+
+def main():
+    """Run tests based on command line arguments."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'VorgabenUI.settings')
+    
+    if len(sys.argv) > 1:
+        command = sys.argv[1]
+        
+        if command == 'all':
+            # Run all tests
+            execute_from_command_line(['manage.py', 'test', '--verbosity=2'])
+        
+        elif command == 'cache':
+            # Run only cache tests
+            execute_from_command_line(['manage.py', 'test', 'diagramm_proxy', '--verbosity=2'])
+        
+        elif command == 'render':
+            # Run only rendering tests
+            execute_from_command_line(['manage.py', 'test', 'abschnitte.tests', '--verbosity=2'])
+        
+        elif command == 'commands':
+            # Run only management command tests
+            execute_from_command_line(['manage.py', 'test', 'abschnitte.management.commands', '--verbosity=2'])
+        
+        elif command == 'coverage':
+            # Run tests with coverage
+            try:
+                import coverage
+                cov = coverage.Coverage(source=['.'])
+                cov.start()
+                
+                execute_from_command_line(['manage.py', 'test', '--verbosity=2'])
+                
+                cov.stop()
+                cov.save()
+                
+                print('\n' + '='*70)
+                print('COVERAGE REPORT')
+                print('='*70)
+                cov.report()
+                
+                print('\nHTML coverage report generated in htmlcov/')
+                cov.html_report()
+                
+            except ImportError:
+                print('ERROR: coverage.py not installed.')
+                print('Install with: pip install coverage')
+                sys.exit(1)
+        
+        elif command == 'fast':
+            # Run tests with failfast
+            execute_from_command_line(['manage.py', 'test', '--failfast', '--verbosity=2'])
+        
+        elif command == 'help':
+            print_help()
+        
+        else:
+            # Pass through to Django test runner
+            execute_from_command_line(['manage.py', 'test'] + sys.argv[1:])
+    
+    else:
+        print_help()
+
+
+def print_help():
+    """Print help message."""
+    help_text = """
+Usage: python run_tests.py [command]
+
+Commands:
+  all         Run all tests
+  cache       Run diagram cache tests only
+  render      Run rendering tests only
+  commands    Run management command tests only
+  coverage    Run tests with coverage report
+  fast        Run tests with fail-fast option
+  help        Show this help message
+
+Advanced:
+  You can also pass standard Django test arguments:
+    python run_tests.py <app_label>
+    python run_tests.py <app_label.TestCase>
+    python run_tests.py <app_label.TestCase.test_method>
+
+Examples:
+  python run_tests.py all
+  python run_tests.py cache
+  python run_tests.py coverage
+  python run_tests.py diagramm_proxy.test_diagram_cache.DiagramCacheTestCase
+  python run_tests.py abschnitte.tests.RenderTextabschnitteTestCase.test_render_diagram_success
+
+For more options, see Documentation/TESTING.md
+"""
+    print(help_text)
+
+
+if __name__ == '__main__':
+    main()