diff --git a/tests/test_cache.py b/tests/test_cache.py
new file mode 100644
index 0000000..5d1a1a0
--- /dev/null
+++ b/tests/test_cache.py
@@ -0,0 +1,117 @@
+"""Tests for cache.py."""
+
+import json
+import tempfile
+from datetime import datetime, timedelta
+from pathlib import Path
+
+import pytest
+
+from gitignore_generator.cache import CacheManager
+
+
+class TestCacheManager:
+    """Tests for CacheManager class."""
+
+    @pytest.fixture
+    def cache_dir(self, tmp_path):
+        """Create temp cache directory."""
+        return tmp_path
+
+    @pytest.fixture
+    def cache(self, cache_dir):
+        """Create cache manager with temp directory."""
+        cache = CacheManager()
+        cache._cache_dir = cache_dir
+        return cache
+
+    def test_set_and_get(self, cache):
+        """Test setting and getting cached items."""
+        cache.set('python', 'python content')
+        result = cache.get('python')
+        assert result == 'python content'
+
+    def test_get_nonexistent(self, cache):
+        """Test getting non-existent item."""
+        result = cache.get('nonexistent_xyz_123')
+        assert result is None
+
+    def test_is_valid_fresh_cache(self, cache):
+        """Test cache validity for fresh items."""
+        cache.set('python', 'content')
+        assert cache.is_valid('python') is True
+
+    def test_is_valid_expired_cache(self, cache):
+        """Test cache validity for expired items."""
+        cache.set('python', 'content')
+
+        metadata = cache._load_metadata()
+        metadata['python']['cached_at'] = (datetime.now() - timedelta(days=10)).isoformat()
+        cache._save_metadata(metadata)
+
+        assert cache.is_valid('python') is False
+
+    def test_invalidate(self, cache):
+        """Test invalidating cached item."""
+        cache.set('python', 'content')
+        assert cache.invalidate('python') is True
+        assert cache.get('python') is None
+
+    def test_invalidate_nonexistent(self, cache):
+        """Test invalidating non-existent item."""
+        assert cache.invalidate('nonexistent_xyz_123') is False
+
+    def test_clear(self, cache):
+        """Test clearing all cache."""
+        cache.set('python', 'content')
+        cache.set('node', 'content')
+        cache.set('django', 'content')
+
+        count = cache.clear()
+        assert count == 3
+        assert cache.get('python') is None
+        assert cache.get('node') is None
+        assert cache.get('django') is None
+
+    def test_get_stats(self, cache):
+        """Test getting cache statistics."""
+        cache.set('python', 'content')
+        cache.set('node', 'content')
+
+        stats = cache.get_stats()
+        assert stats['total_items'] == 2
+        assert stats['valid_items'] == 2
+        assert stats['expired_items'] == 0
+
+    def test_get_age(self, cache):
+        """Test getting cache age."""
+        cache.set('python', 'content')
+        age = cache.get_age('python')
+        assert age is not None
+        assert age >= 0
+
+    def test_get_age_nonexistent(self, cache):
+        """Test getting age of non-existent item."""
+        age = cache.get_age('nonexistent_xyz_123')
+        assert age is None
+
+    def test_cleanup_expired(self, cache):
+        """Test cleaning up expired entries."""
+        cache.set('fresh', 'content')
+
+        metadata = cache._load_metadata()
+        metadata['expired'] = {
+            'cached_at': (datetime.now() - timedelta(days=10)).isoformat(),
+            'size': 100
+        }
+        cache._save_metadata(metadata)
+
+        count = cache.cleanup_expired()
+        assert count == 1
+        assert cache.get('expired') is None
+        assert cache.get('fresh') == 'content'
+
+    def test_cache_directory_creation(self, cache):
+        """Test that cache directory is created."""
+        cache.set('test', 'content')
+        assert cache._cache_dir.exists()