diff --git a/src/vs/workbench/parts/debug/test/common/replHistory.test.ts b/src/vs/workbench/parts/debug/test/common/replHistory.test.ts
new file mode 100644
index 0000000000000000000000000000000000000000..1da7fe5b94e364aa4e5a9b7d4d6eb6ad357e29c1
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+++ b/src/vs/workbench/parts/debug/test/common/replHistory.test.ts
@@ -0,0 +1,47 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import assert = require('assert');
+import { ReplHistory } from 'vs/workbench/parts/debug/common/replHistory';
+
+suite('Debug - Repl History', () => {
+	var history: ReplHistory;
+
+	setup(() => {
+		history = new ReplHistory(['one', 'two', 'three', 'four', 'five']);
+	});
+
+	teardown(() => {
+		history = null;
+	});
+
+	test('previous and next', () => {
+		assert.equal(history.previous(), 'five');
+		assert.equal(history.previous(), 'four');
+		assert.equal(history.previous(), 'three');
+		assert.equal(history.previous(), 'two');
+		assert.equal(history.previous(), 'one');
+		assert.equal(history.previous(), null);
+		assert.equal(history.next(), 'two');
+		assert.equal(history.next(), 'three');
+		assert.equal(history.next(), 'four');
+		assert.equal(history.next(), 'five');
+	});
+
+	test('evaluated and remember', () => {
+		history.evaluated('six');
+		assert.equal(history.previous(), 'six');
+		assert.equal(history.previous(), 'five');
+		assert.equal(history.next(), 'six');
+
+		history.remember('six++', true);
+		assert.equal(history.next(), 'six++');
+		assert.equal(history.previous(), 'six');
+
+		history.evaluated('seven');
+		assert.equal(history.previous(), 'seven');
+		assert.equal(history.previous(), 'six');
+	});
+});