added test

Author: darangi

spec/text-buffer-spec.js

@@ -0,0 +1,14 @@
+const path = require('path');
+const TextBuffer = require ('../src/text-buffer');
+
+describe('when a buffer is already open', () => {
+  it('replaces foo( with bar( using /\bfoo\(\b/gim', () => {
+    const filePath = path.join(__dirname, 'fixtures','sample.js');
+    const buffer = new TextBuffer();
+    buffer.setPath(filePath);
+    buffer.setText('foo(x)');
+    buffer.replace(/\bfoo\(\b/gim,'bar(');
+
+    expect(buffer.getText()).toBe('bar(x)');
+  });
+});