diff --git a/src/vs/editor/test/common/core/editorState.test.ts b/src/vs/editor/test/common/core/editorState.test.ts
new file mode 100644
index 00000000000..22b5bf36885
--- /dev/null
+++ b/src/vs/editor/test/common/core/editorState.test.ts
@@ -0,0 +1,108 @@
+/*---------------------------------------------------------------------------------------------
+ *  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 URI from 'vs/base/common/uri';
+import { CodeEditorStateFlag, ICommonCodeEditor, IModel } from 'vs/editor/common/editorCommon';
+import { EditorState } from 'vs/editor/common/core/editorState';
+import { Selection } from 'vs/editor/common/core/selection';
+import { Position } from 'vs/editor/common/core/position';
+
+interface IStubEditorState {
+	model?: { uri?: URI, version?: number };
+	position?: Position;
+	selection?: Selection;
+	scroll?: { left?: number, top?: number };
+}
+
+suite('Editor Core - Editor State', () => {
+
+	const allFlags = Object.keys(CodeEditorStateFlag)
+							.map(k => CodeEditorStateFlag[k])
+							.filter(v => typeof v === 'number') as number[];
+
+
+	test('empty editor state should be valid', () => {
+		let result = validate( {}, {} );
+		assert.equal(result, true);
+	});
+
+	test('different model URIs should be invalid', () => {
+		let result = validate(
+				{ model: { uri: URI.parse('http://test1') } },
+				{ model: { uri: URI.parse('http://test2') } }
+			);
+
+		assert.equal(result, false);
+	});
+
+	test('different model versions should be invalid', () => {
+		let result = validate(
+				{ model: { version: 1 } },
+				{ model: { version: 2 } }
+			);
+
+		assert.equal(result, false);
+	});
+
+	test('different positions should be invalid', () => {
+		let result = validate(
+				{ position: new Position(1, 2) },
+				{ position: new Position(2, 3) }
+			);
+
+		assert.equal(result, false);
+	});
+
+	test('different selections should be invalid', () => {
+		let result = validate(
+				{ selection: new Selection(1, 2, 3, 4) },
+				{ selection: new Selection(5, 2, 3, 4) }
+			);
+
+		assert.equal(result, false);
+	});
+
+	test('different scroll positions should be invalid', () => {
+		let result = validate(
+				{ scroll: { left: 1, top: 2 } },
+				{ scroll: { left: 3, top: 2 } }
+			);
+
+		assert.equal(result, false);
+	});
+
+
+	function validate(source: IStubEditorState, target: IStubEditorState) {
+		let sourceEditor = createEditor(source),
+			targetEditor = createEditor(target);
+
+		let result = new EditorState(sourceEditor, allFlags)
+						.validate(targetEditor);
+
+		return result;
+	}
+
+	function createEditor({ model, position, selection, scroll }: IStubEditorState = {}): ICommonCodeEditor {
+
+		let mappedModel = model
+			? {
+				uri: model.uri ? model.uri : URI.parse('http://dummy.org'),
+				getVersionId: () => model.version
+			}
+			: null;
+
+		return <any>{
+			getModel: (): IModel => <any>mappedModel,
+			getPosition: (): Position => position,
+			getSelection: (): Selection => selection,
+			getScrollLeft: (): number => scroll && scroll.left,
+			getScrollTop: (): number => scroll && scroll.top
+		};
+	}
+
+});
+