Add InMemoryIndex unit tests

pkg/kvcache/kvblock/in_memory_test.go

@@ -29,3 +29,73 @@ func TestInMemoryAddBasic(t *testing.T) {
 	assert.NoError(t, err)
 	testAddBasic(t, index)
 }
+
+func TestInMemoryIndexSize(t *testing.T) {
+	// Test with small size to verify eviction
+	cfg := &kvblock.InMemoryIndexConfig{
+		Size:         2, // Only 2 keys max
+		PodCacheSize: 1, // Pod cache size doesn't matter for this test
+	}
+
+	index, err := kvblock.NewInMemoryIndex(cfg)
+	assert.NoError(t, err)
+
+	ctx := t.Context()
+
+	// Add first key
+	key1 := kvblock.Key{ModelName: "test-model", ChunkHash: 111}
+	err = index.Add(ctx, []kvblock.Key{key1}, []kvblock.PodEntry{{PodIdentifier: "pod1", DeviceTier: "gpu"}})
+	assert.NoError(t, err)
+
+	// Add second key
+	key2 := kvblock.Key{ModelName: "test-model", ChunkHash: 222}
+	err = index.Add(ctx, []kvblock.Key{key2}, []kvblock.PodEntry{{PodIdentifier: "pod2", DeviceTier: "gpu"}})
+	assert.NoError(t, err)
+
+	// Add third key - should evict the first one due to LRU
+	key3 := kvblock.Key{ModelName: "test-model", ChunkHash: 333}
+	err = index.Add(ctx, []kvblock.Key{key3}, []kvblock.PodEntry{{PodIdentifier: "pod3", DeviceTier: "cpu"}})
+	assert.NoError(t, err)
+
+	// Lookup should only return the last two keys
+	podsPerKey, err := index.Lookup(ctx, []kvblock.Key{key1, key2, key3}, nil)
+	assert.NoError(t, err)
+
+	assert.Len(t, podsPerKey, 2) // Only key2 and key3 should be present
+	assert.Len(t, podsPerKey[key2], 1)
+	assert.Len(t, podsPerKey[key3], 1)
+	assert.Contains(t, podsPerKey[key2], "pod2")
+	assert.Contains(t, podsPerKey[key3], "pod3")
+}
+
+func TestInMemoryIndexPodCacheSize(t *testing.T) {
+	// Test with small limits to verify enforcement
+	cfg := &kvblock.InMemoryIndexConfig{
+		Size:         1, // Only 1 key max
+		PodCacheSize: 2, // Only 2 pods per key
+	}
+
+	index, err := kvblock.NewInMemoryIndex(cfg)
+	assert.NoError(t, err)
+
+	// Test PodCacheSize limit: add more pods than the limit for one key
+	key := kvblock.Key{ModelName: "test-model", ChunkHash: 111}
+	pods := []kvblock.PodEntry{
+		{PodIdentifier: "pod1", DeviceTier: "gpu"},
+		{PodIdentifier: "pod2", DeviceTier: "gpu"},
+		{PodIdentifier: "pod3", DeviceTier: "cpu"}, // This should evict pod1 due to LRU
+	}
+
+	ctx := t.Context()
+
+	err = index.Add(ctx, []kvblock.Key{key}, pods)
+	assert.NoError(t, err)
+
+	// Lookup should only return 2 pods (pod2 and pod3), pod1 should be evicted
+	podsPerKey, err := index.Lookup(ctx, []kvblock.Key{key}, nil)
+	assert.NoError(t, err)
+	assert.Len(t, podsPerKey, 1)
+	assert.Len(t, podsPerKey[key], 2, "Should only have 2 pods due to PodCacheSize limit")
+	assert.Contains(t, podsPerKey[key], "pod2")
+	assert.Contains(t, podsPerKey[key], "pod3")
+}