anchor.diff:      when(procedure.name).thenReturn(Name('toString'));
       when(procedure.annotations).thenReturn(const <Expression>[]);
       when(procedure.enclosingLibrary).thenReturn(library);
  -    when(procedure.enclosingClass).thenReturn(Class());
  +    when(procedure.enclosingClass).thenReturn(Class(name: 'foo'));
       when(procedure.isAbstract).thenReturn(true);
       when(procedure.isStatic).thenReturn(false);
       when(function.body).thenReturn(statement);
  
positive.code:     when(procedure.name).thenReturn(name);
      when(procedure.annotations).thenReturn(const <Expression>[]);
      when(procedure.enclosingLibrary).thenReturn(library);
      when(procedure.enclosingClass).thenReturn(Class());
      when(procedure.isAbstract).thenReturn(false);
      when(procedure.isStatic).thenReturn(false);
      when(function.body).thenReturn(statement);
  
negative.code:     when(procedure.name).thenReturn(Name('toString'));
      when(procedure.annotations).thenReturn(const <Expression>[]);
      when(procedure.enclosingLibrary).thenReturn(library);
      when(procedure.enclosingClass).thenReturn(Class(name: 'foo'));
      when(procedure.isAbstract).thenReturn(false);
      when(procedure.isStatic).thenReturn(false);
      when(function.body).thenReturn(statement);
  