title: Can I use `expect.stringContaining()` inside a Jest `.toHaveBeenCalledWith()` block?
body: <p>Is it possible to use <code>expect.stringContaining()</code> inside a Jest <code>.toHaveBeenCalledWith()</code> block?</p>
  
  <p>I am currently using:</p>
  
  <pre><code>expect(createChatRoomMock).toHaveBeenCalledWith({
    creatorId: expect.stringContaining("user_"),
    chatRoomUuid: expect.stringContaining("chatRoom_"),
  });
  </code></pre>
  
  <p>But this fails with:</p>
  
  <pre><code>
      - Expected
      + Received
  
  
      Object {
    -   "chatRoomUuid": StringContaining "chatRoom_",
    -   "creatorId": StringContaining "user_",
    +   "chatRoomUuid": "chatRoom_sZ9nj4hC46e4bGz4PjYzpC",
    +   "creatorId": "user_nCQsasvYirUwwoEr3j8HsC",
      },
  </code></pre>
  
  <p>This is odd, as you can see from the error, the recieved strings match what's expected </p>
  
  <p>I've also tried:</p>
  
  <pre><code>expect(createChatRoomMock).toHaveBeenCalledWith({
    creatorId: expect.stringMatching(/user_.*/),
    chatRoomUuid: expect.stringMatching(/chatRoom_.*/),
  });
  </code></pre>
  
  <p>With the same results as shown above.</p>
  
  <p><strong>How can I use <code>expect.stringContaining()</code> inside a Jest <code>.toHaveBeenCalledWith()</code> block?</strong></p>