feat(viz-platform): complete Sprint 1 - plugin structure and tests

Sprint 1 - viz-platform Plugin completed (13/13 issues):
- Commands: 7 files (initial-setup, chart, dashboard, theme, theme-new, theme-css, component)
- Agents: 3 files (theme-setup, layout-builder, component-check)
- Documentation: README.md, claude-md-integration.md
- Tests: 94 tests passing (68-99% coverage)
- CHANGELOG updated with completion status

Closes: #178, #179, #180, #181, #182

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

mcp-servers/viz-platform/tests/test_config.py

@@ -0,0 +1,156 @@
+"""
+Unit tests for viz-platform configuration loader.
+"""
+import pytest
+import os
+from pathlib import Path
+from unittest.mock import patch, MagicMock
+
+
+@pytest.fixture
+def clean_env():
+    """Clean environment variables before test"""
+    env_vars = ['DMC_VERSION', 'CLAUDE_PROJECT_DIR', 'VIZ_DEFAULT_THEME']
+    saved = {k: os.environ.get(k) for k in env_vars}
+    for k in env_vars:
+        if k in os.environ:
+            del os.environ[k]
+    yield
+    # Restore after test
+    for k, v in saved.items():
+        if v is not None:
+            os.environ[k] = v
+        elif k in os.environ:
+            del os.environ[k]
+
+
+@pytest.fixture
+def config():
+    """Create VizPlatformConfig instance"""
+    from mcp_server.config import VizPlatformConfig
+    return VizPlatformConfig()
+
+
+def test_config_init(config):
+    """Test config initialization"""
+    assert config.dmc_version is None
+    assert config.theme_dir_user == Path.home() / '.config' / 'claude' / 'themes'
+    assert config.theme_dir_project is None
+    assert config.default_theme is None
+
+
+def test_config_load_returns_dict(config, clean_env):
+    """Test config.load() returns expected structure"""
+    result = config.load()
+
+    assert isinstance(result, dict)
+    assert 'dmc_version' in result
+    assert 'dmc_available' in result
+    assert 'theme_dir_user' in result
+    assert 'theme_dir_project' in result
+    assert 'default_theme' in result
+    assert 'project_dir' in result
+
+
+def test_config_respects_env_dmc_version(config, clean_env):
+    """Test that DMC_VERSION env var is respected"""
+    os.environ['DMC_VERSION'] = '0.14.7'
+
+    result = config.load()
+
+    assert result['dmc_version'] == '0.14.7'
+    assert result['dmc_available'] is True
+
+
+def test_config_respects_default_theme_env(config, clean_env):
+    """Test that VIZ_DEFAULT_THEME env var is respected"""
+    os.environ['VIZ_DEFAULT_THEME'] = 'my-dark-theme'
+
+    result = config.load()
+
+    assert result['default_theme'] == 'my-dark-theme'
+
+
+def test_detect_dmc_version_not_installed(config):
+    """Test DMC version detection when not installed"""
+    with patch('importlib.metadata.version', side_effect=ImportError("not installed")):
+        version = config._detect_dmc_version()
+
+    assert version is None
+
+
+def test_detect_dmc_version_installed(config):
+    """Test DMC version detection when installed"""
+    with patch('importlib.metadata.version', return_value='0.14.7'):
+        version = config._detect_dmc_version()
+
+    assert version == '0.14.7'
+
+
+def test_find_project_directory_from_env(config, clean_env, tmp_path):
+    """Test project directory detection from CLAUDE_PROJECT_DIR"""
+    os.environ['CLAUDE_PROJECT_DIR'] = str(tmp_path)
+
+    result = config._find_project_directory()
+
+    assert result == tmp_path
+
+
+def test_find_project_directory_with_git(config, clean_env, tmp_path):
+    """Test project directory detection with .git folder"""
+    git_dir = tmp_path / '.git'
+    git_dir.mkdir()
+
+    with patch.dict(os.environ, {'PWD': str(tmp_path)}):
+        result = config._find_project_directory()
+
+    assert result == tmp_path
+
+
+def test_find_project_directory_with_env_file(config, clean_env, tmp_path):
+    """Test project directory detection with .env file"""
+    env_file = tmp_path / '.env'
+    env_file.touch()
+
+    with patch.dict(os.environ, {'PWD': str(tmp_path)}):
+        result = config._find_project_directory()
+
+    assert result == tmp_path
+
+
+def test_load_config_convenience_function(clean_env):
+    """Test the convenience function load_config()"""
+    from mcp_server.config import load_config
+
+    result = load_config()
+
+    assert isinstance(result, dict)
+    assert 'dmc_version' in result
+
+
+def test_check_dmc_version_not_installed(clean_env):
+    """Test check_dmc_version when DMC not installed"""
+    from mcp_server.config import check_dmc_version
+
+    with patch('mcp_server.config.load_config', return_value={'dmc_available': False}):
+        result = check_dmc_version()
+
+    assert result['installed'] is False
+    assert 'not installed' in result['message'].lower()
+
+
+def test_check_dmc_version_installed_with_registry(clean_env, tmp_path):
+    """Test check_dmc_version when DMC installed with matching registry"""
+    from mcp_server.config import check_dmc_version
+
+    mock_config = {
+        'dmc_available': True,
+        'dmc_version': '2.5.1'
+    }
+
+    with patch('mcp_server.config.load_config', return_value=mock_config):
+        with patch('pathlib.Path.exists', return_value=True):
+            result = check_dmc_version()
+
+    assert result['installed'] is True
+    assert result['version'] == '2.5.1'