code: public static boolean isCase(Map caseValue, Object switchValue) {
          return DefaultTypeTransformation.castToBoolean(caseValue.get(switchValue));
      }
docs: 'Case' implementation for maps which tests the groovy truth
  value obtained using the 'switch' operand as key.
  For example:
  <pre class="groovyTestCase">switch( 'foo' ) {
  case [foo:true, bar:false]:
  assert true
  break
  default:
  assert false
  }</pre>
  
  @param caseValue   the case value
  @param switchValue the switch value
  @return the groovy truth value from caseValue corresponding to the switchValue key
  @since 1.7.6