title: Wiremock verify headers contains many values via custom ValueMatcherStrategy
body: <p>I'm using wiremock to test a client. One particular test is to verify that the client send one header with a comma separated list of values. 
  However those values are from an unordered collection. So it can be <code>first,second</code> or <code>second,first</code> and both are valids.</p>
  
  <p>Sadly, I cannot find any <code>ValueMatchingStrategy</code> that can be used for that. <code>containing</code> expect only one value.</p>
  
  <p>I tried to build a custom <code>ValueMatcherStratgey</code> but the <code>isMatchFor</code> method is never called.</p>
  
  <pre><code>new ValueMatchingStrategy(){
      @Override
      public ValuePattern asValuePattern() {
          return new ValuePattern(){
              @Override
              public boolean isMatchFor(String value) {
                  return value.contains("first") &amp;&amp; 
                         value.contains("second") &amp;&amp;
                         value.contains(",");
              }
          };
      }
  }
  </code></pre>
  
  <p>Is there an easier way to verify that a header contains more than one value ? Or how can I create a custom matcher ?</p>