@Test
 public void shouldCreateInstanceOfExistingBlockWhenBlockCalledWithNameOfRegisteredBlock() {
   PrimObject primObject = new PrimObject();
   PrimObject block = mock(PrimObject.class);
   when(block.isMethodBlock()).thenReturn(true);
   PrimObject.BLOCKS.put("st/redline/core/Thing$M1", block);
   primObject.block("st/redline/core/Thing$M1", null);
   // not a test so much as documentation.
 }