diff --git a/src/Buffer.test.ts b/src/Buffer.test.ts
index 2ad86b22..153b6f15 100644
--- a/src/Buffer.test.ts
+++ b/src/Buffer.test.ts
@@ -7,20 +7,12 @@ import { assert } from 'chai';
 import { ITerminal } from './Types';
 import { Buffer, DEFAULT_ATTR, CHAR_DATA_CHAR_INDEX } from './Buffer';
 import { CircularList } from './common/CircularList';
-import { MockTerminal } from './utils/TestUtils.test';
+import { MockTerminal, TestTerminal } from './utils/TestUtils.test';
 import { BufferLine } from './BufferLine';
-import { Terminal } from './Terminal';
 
 const INIT_COLS = 80;
 const INIT_ROWS = 24;
 
-class TestTerminal extends Terminal {
-  writeSync(data: string): void {
-    this.writeBuffer.push(data);
-    this._innerWrite();
-  }
-}
-
 describe('Buffer', () => {
   let terminal: ITerminal;
   let buffer: Buffer;
@@ -355,12 +347,14 @@ describe('Buffer', () => {
       assert.equal(str3, '😁a');
     });
   });
-  describe('stringIndexToBufferIndex', function(): void {
+  describe('stringIndexToBufferIndex', () => {
     let terminal: TestTerminal;
-    beforeEach(function(): void {
+
+    beforeEach(() => {
       terminal = new TestTerminal({rows: 5, cols: 10});
     });
-    it('multiline ascii', function(): void {
+
+    it('multiline ascii', () => {
       const input = 'This is ASCII text spanning multiple lines.';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -370,7 +364,8 @@ describe('Buffer', () => {
         assert.deepEqual([(i / terminal.cols) | 0, i % terminal.cols], bufferIndex);
       }
     });
-    it('combining e\u0301 in a sentence', function(): void {
+
+    it('combining e\u0301 in a sentence', () => {
       const input = 'Sitting in the cafe\u0301 drinking coffee.';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -389,7 +384,8 @@ describe('Buffer', () => {
         assert.deepEqual([((i - 1) / terminal.cols) | 0, (i - 1) % terminal.cols], bufferIndex);
       }
     });
-    it('multiline combining e\u0301', function(): void {
+
+    it('multiline combining e\u0301', () => {
       const input = 'e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -400,7 +396,8 @@ describe('Buffer', () => {
         assert.deepEqual([((i >> 1) / terminal.cols) | 0, (i >> 1) % terminal.cols], bufferIndex);
       }
     });
-    it('surrogate char in a sentence', function(): void {
+
+    it('surrogate char in a sentence', () => {
       const input = 'The 𝄞 is a clef widely used in modern notation.';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -419,7 +416,8 @@ describe('Buffer', () => {
         assert.deepEqual([((i - 1) / terminal.cols) | 0, (i - 1) % terminal.cols], bufferIndex);
       }
     });
-    it('multiline surrogate char', function(): void {
+
+    it('multiline surrogate char', () => {
       const input = '𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -430,7 +428,8 @@ describe('Buffer', () => {
         assert.deepEqual([((i >> 1) / terminal.cols) | 0, (i >> 1) % terminal.cols], bufferIndex);
       }
     });
-    it('surrogate char with combining', function(): void {
+
+    it('surrogate char with combining', () => {
       // eye of Ra with acute accent - string length of 3
       const input = '𓂀\u0301 - the eye hiroglyph with an acute accent.';
       terminal.writeSync(input);
@@ -444,7 +443,8 @@ describe('Buffer', () => {
         assert.deepEqual([((i - 2) / terminal.cols) | 0, (i - 2) % terminal.cols], bufferIndex);
       }
     });
-    it('multiline surrogate with combining', function(): void {
+
+    it('multiline surrogate with combining', () => {
       const input = '𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -455,7 +455,8 @@ describe('Buffer', () => {
         assert.deepEqual([(((i / 3) | 0) / terminal.cols) | 0, ((i / 3) | 0) % terminal.cols], bufferIndex);
       }
     });
-    it('fullwidth chars', function(): void {
+
+    it('fullwidth chars', () => {
       const input = 'These １２３ are some fat numbers.';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -473,7 +474,8 @@ describe('Buffer', () => {
         assert.deepEqual([((i + 3) / terminal.cols) | 0, (i + 3) % terminal.cols], bufferIndex);
       }
     });
-    it('multiline fullwidth chars', function(): void {
+
+    it('multiline fullwidth chars', () => {
       const input = '１２３４５６７８９０１２３４５６７８９０';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -483,7 +485,8 @@ describe('Buffer', () => {
         assert.deepEqual([((i << 1) / terminal.cols) | 0, (i << 1) % terminal.cols], bufferIndex);
       }
     });
-    it('fullwidth combining with emoji - match emoji cell', function(): void {
+
+    it('fullwidth combining with emoji - match emoji cell', () => {
       const input = 'Lots of ￥\u0301 make me 😃.';
       terminal.writeSync(input);
       const s = terminal.buffer.contents(true).toArray()[0];
@@ -492,7 +495,8 @@ describe('Buffer', () => {
       const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, stringIndex);
       assert(terminal.buffer.lines.get(bufferIndex[0]).get(bufferIndex[1])[CHAR_DATA_CHAR_INDEX], '😃');
     });
-    it('multiline fullwidth chars with offset 1 (currently tests for broken behavior)', function(): void {
+
+    it('multiline fullwidth chars with offset 1 (currently tests for broken behavior)', () => {
       const input = 'a１２３４５６７８９０１２３４５６７８９０';
       // the 'a' at the beginning moves all fullwidth chars one to the right
       // now the end of the line contains a dangling empty cell since
diff --git a/src/Linkifier.test.ts b/src/Linkifier.test.ts
index 32b4ee3b..35610acb 100644
--- a/src/Linkifier.test.ts
+++ b/src/Linkifier.test.ts
@@ -7,10 +7,9 @@ import { assert } from 'chai';
 import { IMouseZoneManager, IMouseZone } from './ui/Types';
 import { ILinkMatcher, ITerminal, IBufferLine } from './Types';
 import { Linkifier } from './Linkifier';
-import { MockBuffer, MockTerminal } from './utils/TestUtils.test';
+import { MockBuffer, MockTerminal, TestTerminal } from './utils/TestUtils.test';
 import { CircularList } from './common/CircularList';
 import { BufferLine } from './BufferLine';
-import { Terminal } from './Terminal';
 
 class TestLinkifier extends Linkifier {
   constructor(terminal: ITerminal) {
@@ -239,23 +238,20 @@ describe('Linkifier', () => {
       });
     });
   });
-  describe('unicode handling', function(): void {
+  describe('unicode handling', () => {
+    let terminal: TestTerminal;
+
     // other than the tests above unicode testing needs the full terminal instance
     // to get the special handling of fullwidth, surrogate and combining chars in the input handler
-    beforeEach(function(): void {
-      terminal = new Terminal({cols: 10, rows: 5});
-      const oldWrite: any = terminal.write.bind(terminal);
-      terminal.write = (s: string): void => {
-        oldWrite(s);
-        (terminal as any)._innerWrite();
-      };
+    beforeEach(() => {
+      terminal = new TestTerminal({cols: 10, rows: 5});
       linkifier = new TestLinkifier(terminal);
       mouseZoneManager = new TestMouseZoneManager();
       linkifier.attachToDom(mouseZoneManager);
     });
 
     function assertLinkifiesInTerminal(rowText: string, linkMatcherRegex: RegExp, links: {x1: number, y1: number, x2: number, y2: number}[], done: MochaDone): void {
-      terminal.write(rowText);
+      terminal.writeSync(rowText);
       linkifier.registerLinkMatcher(linkMatcherRegex, () => {});
       linkifier.linkifyRows();
       // Allow linkify to happen
@@ -271,7 +267,7 @@ describe('Linkifier', () => {
       }, 0);
     }
 
-    describe('unicode before the match', function(): void {
+    describe('unicode before the match', () => {
       it('combining - match within one line', function(done: () => void): void {
         assertLinkifiesInTerminal('e\u0301e\u0301e\u0301 foo', /foo/, [{x1: 4, x2: 7, y1: 0, y2: 0}], done);
       });
@@ -303,7 +299,7 @@ describe('Linkifier', () => {
         assertLinkifiesInTerminal('￥\u0301￥\u0301    foo', /foo/, [{x1: 8, x2: 1, y1: 0, y2: 1}], done);
       });
     });
-    describe('unicode within the match', function(): void {
+    describe('unicode within the match', () => {
       it('combining - match within one line', function(done: () => void): void {
         assertLinkifiesInTerminal('test cafe\u0301', /cafe\u0301/, [{x1: 5, x2: 9, y1: 0, y2: 0}], done);
       });
diff --git a/src/Types.ts b/src/Types.ts
index 5652f135..5782f2c9 100644
--- a/src/Types.ts
+++ b/src/Types.ts
@@ -271,6 +271,7 @@ export interface ITerminalOptions extends IPublicTerminalOptions {
 export interface IBufferStringIterator {
   hasNext(): boolean;
   next(withRanges: boolean): string | [{first: number, last: number}, string];
+  toArray(): string[];
 }
 
 export interface IBuffer {
diff --git a/src/utils/TestUtils.test.ts b/src/utils/TestUtils.test.ts
index 6fa0c87a..40a93ded 100644
--- a/src/utils/TestUtils.test.ts
+++ b/src/utils/TestUtils.test.ts
@@ -9,6 +9,14 @@ import { ICircularList, XtermListener } from '../common/Types';
 import { Buffer } from '../Buffer';
 import * as Browser from '../shared/utils/Browser';
 import { ITheme, IDisposable, IMarker } from 'xterm';
+import { Terminal } from '../Terminal';
+
+export class TestTerminal extends Terminal {
+  writeSync(data: string): void {
+    this.writeBuffer.push(data);
+    this._innerWrite();
+  }
+}
 
 export class MockTerminal implements ITerminal {
   markers: IMarker[];