@Theory
    public void shouldReturnTrueWhenContainsKey(int size) throws Exception {
        CaseInsensitiveStringMultiMap actual = new CaseInsensitiveStringMultiMap(size);
        actual.put("a", "b").put("c", "d").put("a", "x");
        Assert.assertTrue(actual.containsKey("a"));
    }
@author Marc Savy {@literal <msavy@redhat.com>}
gateway/engine/beans/src/test/java/io/apiman/gateway/engine/beans/util/CaseInsensitiveStringMultiMapTest.java