Fix and test for MemoryCachingByteStore.

pkg/analyzer/test/src/dart/analysis/byte_store_test.dart

Index: pkg/analyzer/test/src/dart/analysis/byte_store_test.dart
diff --git a/pkg/analyzer/test/src/dart/analysis/byte_store_test.dart b/pkg/analyzer/test/src/dart/analysis/byte_store_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..20998631f997759ece7f3978d0f4f095852632d4
--- /dev/null
+++ b/pkg/analyzer/test/src/dart/analysis/byte_store_test.dart
@@ -0,0 +1,79 @@
+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:analyzer/src/dart/analysis/byte_store.dart';
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+import 'package:typed_mock/typed_mock.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(MemoryCachingByteStoreTest);
+  });
+}
+
+@reflectiveTest
+class MemoryCachingByteStoreTest {
+  test_get_put_evict() {
+    var store = new _TestByteStore();
+    var cachingStore = new MemoryCachingByteStore(store, 100);
+
+    // Keys: [1, 2].
+    cachingStore.put('1', _b(40));
+    cachingStore.put('2', _b(50));
+
+    // Request '1', so now it is the most recently used.
+    // Keys: [2, 1].
+    cachingStore.get('1');
+
+    // 40 + 50 + 30 > 100
+    // So, '2' is evicted.
+    cachingStore.put('3', _b(30));
+    expect(cachingStore.get('1'), hasLength(40));
+    expect(cachingStore.get('2'), isNull);
+    expect(cachingStore.get('3'), hasLength(30));
+  }
+
+  test_put_evict_first() {
+    var store = new _TestByteStore();
+    var cachingStore = new MemoryCachingByteStore(store, 100);
+
+    // 40 + 50 < 100
+    cachingStore.put('1', _b(40));
+    cachingStore.put('2', _b(50));
+    expect(cachingStore.get('1'), hasLength(40));
+    expect(cachingStore.get('2'), hasLength(50));
+
+    // 40 + 50 + 30 > 100
+    // So, '1' is evicted.
+    cachingStore.put('3', _b(30));
+    expect(cachingStore.get('1'), isNull);
+    expect(cachingStore.get('2'), hasLength(50));
+    expect(cachingStore.get('3'), hasLength(30));
+  }
+
+  test_put_evict_firstAndSecond() {
+    var store = new _TestByteStore();
+    var cachingStore = new MemoryCachingByteStore(store, 100);
+
+    // 10 + 80 < 100
+    cachingStore.put('1', _b(10));
+    cachingStore.put('2', _b(80));
+    expect(cachingStore.get('1'), hasLength(10));
+    expect(cachingStore.get('2'), hasLength(80));
+
+    // 10 + 80 + 30 > 100
+    // So, '1' and '2' are evicted.
+    cachingStore.put('3', _b(30));
+    expect(cachingStore.get('1'), isNull);
+    expect(cachingStore.get('2'), isNull);
+    expect(cachingStore.get('3'), hasLength(30));
+  }
+
+  static List<int> _b(int length) {
+    return new List<int>(length);
+  }
+}
+
+class _TestByteStore extends TypedMock implements ByteStore {}