old_contents: from flask import json
  from nose.tools import eq_
  from server import app
  
  client = app.test_client()
  
  
  def test_hello_world():
      # When: I access root path
      resp = client.get('/')
  
      # Then: Expected response is returned
      eq_(resp.status_code, 200)
      eq_(resp.headers['Content-Type'], 'application/json')
      data = json.loads(resp.data.decode())
      eq_(data['message'], 'Hello Worlb!')
  
new_contents: from flask import json
  from nose.tools import eq_
  from server import app
  
  client = app.test_client()
  
  
  def test_hello_world():
      # When: I access root path
      resp = client.get('/')
  
      # Then: Expected response is returned
      eq_(resp.status_code, 200)
      eq_(resp.headers['Content-Type'], 'application/json')
      data = json.loads(resp.data.decode())
      eq_(data['message'].startswith('Hello'), True)
  
subject: Use startswith instead of exact string match