extract Cache class

src/vs/base/test/common/cache.test.ts

@@ -0,0 +1,66 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import * as assert from 'assert';
+import Cache from 'vs/base/common/cache';
+import { TPromise } from 'vs/base/common/winjs.base';
+
+suite('Cache', () => {
+
+	test('simple value', () => {
+		let counter = 0;
+		const cache = new Cache(() => TPromise.as(counter++));
+
+		return cache.get()
+			.then(c => assert.equal(c, 0), () => assert.fail())
+			.then(() => cache.get())
+			.then(c => assert.equal(c, 0), () => assert.fail());
+	});
+
+	test('simple error', () => {
+		let counter = 0;
+		const cache = new Cache(() => TPromise.wrapError(counter++));
+
+		return cache.get()
+			.then(() => assert.fail(), err => assert.equal(err, 0))
+			.then(() => cache.get())
+			.then(() => assert.fail(), err => assert.equal(err, 0));
+	});
+
+	test('should retry cancellations', () => {
+		let counter1 = 0, counter2 = 0;
+
+		const cache = new Cache(() => {
+			counter1++;
+			return TPromise.timeout(1).then(() => counter2++);
+		});
+
+		assert.equal(counter1, 0);
+		assert.equal(counter2, 0);
+		let promise = cache.get();
+		assert.equal(counter1, 1);
+		assert.equal(counter2, 0);
+		promise.cancel();
+		assert.equal(counter1, 1);
+		assert.equal(counter2, 0);
+
+		promise = cache.get();
+		assert.equal(counter1, 2);
+		assert.equal(counter2, 0);
+
+		return promise
+			.then(c => {
+				assert.equal(counter1, 2);
+				assert.equal(counter2, 1);
+			})
+			.then(() => cache.get())
+			.then(c => {
+				assert.equal(counter1, 2);
+				assert.equal(counter2, 1);
+			});
+	});
+});