diff --git a/tests/test_cache_manager.py b/tests/test_cache_manager.py
new file mode 100644
index 0000000..ff1651c
--- /dev/null
+++ b/tests/test_cache_manager.py
@@ -0,0 +1,127 @@
+"""Tests for the cache manager."""
+
+import tempfile
+import time
+from pathlib import Path
+
+import pytest
+from src.cache_manager import CacheManager
+
+
+class TestCacheManager:
+    """Tests for CacheManager class."""
+
+    @pytest.fixture
+    def temp_cache_dir(self):
+        """Create a temporary cache directory."""
+        with tempfile.TemporaryDirectory() as tmpdir:
+            yield Path(tmpdir)
+
+    @pytest.fixture
+    def cache_manager(self, temp_cache_dir):
+        """Create a cache manager with temp directory."""
+        return CacheManager(cache_dir=temp_cache_dir, ttl=60)
+
+    def test_set_and_get(self, cache_manager):
+        """Test setting and getting values."""
+        cache_manager.set("test_key", "test_value")
+        result = cache_manager.get("test_key")
+
+        assert result == "test_value"
+
+    def test_get_nonexistent_key(self, cache_manager):
+        """Test getting a key that doesn't exist."""
+        result = cache_manager.get("nonexistent_key")
+
+        assert result is None
+
+    def test_set_complex_value(self, cache_manager):
+        """Test setting and getting complex values."""
+        data = {
+            "repo": "test/repo",
+            "matches": ["match1", "match2"],
+            "count": 5,
+        }
+        cache_manager.set("complex_key", data)
+        result = cache_manager.get("complex_key")
+
+        assert result == data
+
+    def test_delete(self, cache_manager):
+        """Test deleting a value."""
+        cache_manager.set("delete_key", "value")
+        assert cache_manager.get("delete_key") == "value"
+
+        result = cache_manager.delete("delete_key")
+        assert result is True
+        assert cache_manager.get("delete_key") is None
+
+    def test_delete_nonexistent(self, cache_manager):
+        """Test deleting a key that doesn't exist."""
+        result = cache_manager.delete("nonexistent")
+        assert result is False
+
+    def test_clear(self, cache_manager):
+        """Test clearing all cache values."""
+        cache_manager.set("key1", "value1")
+        cache_manager.set("key2", "value2")
+
+        result = cache_manager.clear()
+        assert result is True
+        assert cache_manager.get("key1") is None
+        assert cache_manager.get("key2") is None
+
+    def test_get_stats(self, cache_manager):
+        """Test getting cache statistics."""
+        cache_manager.set("key", "value")
+        stats = cache_manager.get_stats()
+
+        assert "size" in stats
+        assert "hits" in stats
+        assert "misses" in stats
+        assert "cache_size_mb" in stats
+        assert isinstance(stats["cache_size_mb"], float)
+
+    def test_get_all(self, cache_manager):
+        """Test getting all cached entries."""
+        cache_manager.set("key1", "value1")
+        cache_manager.set("key2", "value2")
+
+        entries = cache_manager.get_all()
+
+        assert len(entries) >= 2
+
+    def test_key_is_hashed(self, cache_manager):
+        """Test that keys are hashed."""
+        cache_manager.set("test_key", "value")
+        entries = cache_manager.get_all()
+
+        assert "test_key" not in entries
+
+    def test_cleanup(self, cache_manager):
+        """Test cleaning up expired entries."""
+        cache_manager.set("key", "value")
+        removed = cache_manager.cleanup()
+
+        assert isinstance(removed, int)
+
+
+class TestCacheManagerTTL:
+    """Tests for cache TTL functionality."""
+
+    @pytest.fixture
+    def temp_cache_dir(self):
+        """Create a temporary cache directory."""
+        with tempfile.TemporaryDirectory() as tmpdir:
+            yield Path(tmpdir)
+
+    def test_ttl_expiration(self, temp_cache_dir):
+        """Test that cached values expire after TTL."""
+        cache_manager = CacheManager(cache_dir=temp_cache_dir, ttl=1)
+
+        cache_manager.set("expiring_key", "value")
+        assert cache_manager.get("expiring_key") == "value"
+
+        time.sleep(1.5)
+
+        assert cache_manager.get("expiring_key") is None