diff --git a/fixtures/typings-test/typings-test.ts b/fixtures/typings-test/typings-test.ts
index ffe6afd49..90958f83f 100644
--- a/fixtures/typings-test/typings-test.ts
+++ b/fixtures/typings-test/typings-test.ts
@@ -210,8 +210,8 @@ namespace methods_experimental {
     t.registerLinkMatcher(/foo/, () => true, {
       matchIndex: 1,
       priority: 1,
-      validationCallback: (uri: string, element: HTMLElement, callback: (isValid: boolean) => void) => {
-        console.log(uri, element, callback);
+      validationCallback: (uri: string, callback: (isValid: boolean) => void) => {
+        console.log(uri, callback);
       }
     });
     t.deregisterLinkMatcher(1);
diff --git a/src/CompositionHelper.test.ts b/src/CompositionHelper.test.ts
index 0adb1719a..7d78a259b 100644
--- a/src/CompositionHelper.test.ts
+++ b/src/CompositionHelper.test.ts
@@ -42,6 +42,16 @@ describe('CompositionHelper', () => {
       },
       handler: (text: string) => {
         handledText += text;
+      },
+      buffer: {
+        isCursorInViewport: true
+      },
+      charMeasure: {
+        height: 10,
+        width: 10
+      },
+      options: {
+        lineHeight: 1
       }
     };
     handledText = '';
diff --git a/src/Terminal.test.ts b/src/Terminal.test.ts
index 0c333741f..7a44ee81e 100644
--- a/src/Terminal.test.ts
+++ b/src/Terminal.test.ts
@@ -1,6 +1,6 @@
 import { assert, expect } from 'chai';
 import { Terminal } from './Terminal';
-import { MockViewport, MockCompositionHelper } from './utils/TestUtils.test';
+import { MockViewport, MockCompositionHelper, MockRenderer } from './utils/TestUtils.test';
 import { CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX } from './Buffer';
 
 const INIT_COLS = 80;
@@ -21,6 +21,7 @@ describe('term.js addons', () => {
       rows: INIT_ROWS
     });
     term.refresh = () => {};
+    (<any>term).renderer = new MockRenderer();
     term.viewport = new MockViewport();
     (<any>term).compositionHelper = new MockCompositionHelper();
     // Force synchronous writes
diff --git a/src/Terminal.ts b/src/Terminal.ts
index 620340171..cab25b03b 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -44,6 +44,7 @@ import { DEFAULT_ANSI_COLORS } from './renderer/ColorManager';
 import { IMouseZoneManager } from './input/Interfaces';
 import { MouseZoneManager } from './input/MouseZoneManager';
 import { initialize as initializeCharAtlas } from './renderer/CharAtlas';
+import { IRenderer } from './renderer/Interfaces';
 
 // Declare for RequireJS in loadAddon
 declare var define: any;
@@ -184,7 +185,7 @@ export class Terminal extends EventEmitter implements ITerminal, IInputHandlingT
 
   private inputHandler: InputHandler;
   private parser: Parser;
-  private renderer: Renderer;
+  private renderer: IRenderer;
   public selectionManager: SelectionManager;
   private linkifier: Linkifier;
   public buffers: BufferSet;
diff --git a/src/Viewport.test.ts b/src/Viewport.test.ts
index 8a960fc7d..6d23e19a1 100644
--- a/src/Viewport.test.ts
+++ b/src/Viewport.test.ts
@@ -31,7 +31,8 @@ describe('Viewport', () => {
         }
       },
       options: {
-        scrollback: 10
+        scrollback: 10,
+        lineHeight: 1
       }
     };
     terminal.buffers = new BufferSet(terminal);
diff --git a/src/renderer/Interfaces.ts b/src/renderer/Interfaces.ts
index fd94d59d7..f7645abf8 100644
--- a/src/renderer/Interfaces.ts
+++ b/src/renderer/Interfaces.ts
@@ -1,4 +1,17 @@
-import { ITerminal, ITerminalOptions } from '../Interfaces';
+import { ITerminal, ITerminalOptions, ITheme } from '../Interfaces';
+
+export interface IRenderer {
+  setTheme(theme: ITheme): IColorSet;
+  onResize(cols: number, rows: number): void;
+  onCharSizeChanged(charWidth: number, charHeight: number): void;
+  onBlur(): void;
+  onFocus(): void;
+  onSelectionChanged(start: [number, number], end: [number, number]): void;
+  onCursorMove(): void;
+  onOptionsChanged(): void;
+  clear(): void;
+  queueRefresh(start: number, end: number): void;
+}
 
 export interface IRenderLayer {
   /**
diff --git a/src/renderer/Renderer.ts b/src/renderer/Renderer.ts
index bc0717dc4..6b12188ed 100644
--- a/src/renderer/Renderer.ts
+++ b/src/renderer/Renderer.ts
@@ -11,9 +11,9 @@ import { SelectionRenderLayer } from './SelectionRenderLayer';
 import { CursorRenderLayer } from './CursorRenderLayer';
 import { ColorManager } from './ColorManager';
 import { BaseRenderLayer } from './BaseRenderLayer';
-import { IRenderLayer, IColorSet } from './Interfaces';
+import { IRenderLayer, IColorSet, IRenderer } from './Interfaces';
 
-export class Renderer {
+export class Renderer implements IRenderer {
   /** A queue of the rows to be refreshed */
   private _refreshRowsQueue: {start: number, end: number}[] = [];
   private _refreshAnimationFrame = null;
diff --git a/src/utils/TestUtils.test.ts b/src/utils/TestUtils.test.ts
index 0388e9da1..51f191a83 100644
--- a/src/utils/TestUtils.test.ts
+++ b/src/utils/TestUtils.test.ts
@@ -2,11 +2,11 @@
  * @license MIT
  */
 
-import { ITerminal, IBuffer, IBufferSet, IBrowser, ICharMeasure, ISelectionManager, ITerminalOptions, IListenerType, IInputHandlingTerminal, IViewport, ICircularList, ICompositionHelper } from '../Interfaces';
+import { ITerminal, IBuffer, IBufferSet, IBrowser, ICharMeasure, ISelectionManager, ITerminalOptions, IListenerType, IInputHandlingTerminal, IViewport, ICircularList, ICompositionHelper, ITheme } from '../Interfaces';
 import { LineData } from '../Types';
 import { Buffer } from '../Buffer';
 import * as Browser from './Browser';
-import { IColorSet } from '../renderer/Interfaces';
+import { IColorSet, IRenderer } from '../renderer/Interfaces';
 
 export class MockTerminal implements ITerminal {
   isFocused: boolean;
@@ -204,6 +204,19 @@ export class MockBuffer implements IBuffer {
   }
 }
 
+export class MockRenderer implements IRenderer {
+  setTheme(theme: ITheme): IColorSet { return <IColorSet>{}; }
+  onResize(cols: number, rows: number): void {}
+  onCharSizeChanged(charWidth: number, charHeight: number): void {}
+  onBlur(): void {}
+  onFocus(): void {}
+  onSelectionChanged(start: [number, number], end: [number, number]): void {}
+  onCursorMove(): void {}
+  onOptionsChanged(): void {}
+  clear(): void {}
+  queueRefresh(start: number, end: number): void {}
+}
+
 export class MockViewport implements IViewport {
   onThemeChanged(colors: IColorSet): void {
     throw new Error('Method not implemented.');
diff --git a/typings/xterm.d.ts b/typings/xterm.d.ts
index d61279785..866021e87 100644
--- a/typings/xterm.d.ts
+++ b/typings/xterm.d.ts
@@ -131,12 +131,12 @@ interface ILinkMatcherOptions {
    * A callback that validates an individual link, returning true if valid and
    * false if invalid.
    */
-  validationCallback?: (uri: string, element: HTMLElement, callback: (isValid: boolean) => void) => void;
+  validationCallback?: (uri: string, callback: (isValid: boolean) => void) => void;
 
   /**
    * A callback that fired when the mouse hovers over a link.
    */
-  hoverCallback?: LinkMatcherHandler;
+  hoverCallback?: (event: MouseEvent, uri: string) => boolean | void;
 
   /**
    * The priority of the link matcher, this defines the order in which the link
@@ -290,7 +290,7 @@ declare module 'xterm' {
      * @param options Options for the link matcher.
      * @return The ID of the new matcher, this can be used to deregister.
      */
-    registerLinkMatcher(regex: RegExp, handler: (event: MouseEvent, uri: string) => boolean | void , options?: ILinkMatcherOptions): number;
+    registerLinkMatcher(regex: RegExp, handler: (event: MouseEvent, uri: string) => boolean | void, options?: ILinkMatcherOptions): number;
 
     /**
      * (EXPERIMENTAL) Deregisters a link matcher if it has been registered.