@Test
public void writeSuccessfulResponse() {

  String content = "test content";
  String expectedMessage =
      "HTTP/1.0 200 OK"
          + newLine
          + "Content-type: application/json"
          + newLine
          + responseCommon
          + content
          + newLine;
  testSubject.writeSuccessfulResponse(content);
  String writtenMessage = stringWriter.toString();
  Assert.assertEquals(writtenMessage, expectedMessage);
}