@Test
public void testSimpleCase() {

  Parser<Expression> parser = ExpressionParser.simpleCase(NUMBER);
  TerminalParserTest.assertParser(parser, "case 1 when 1 then 2 else 3 end",
      simpleCase(number(1), number(1), number(2), number(3)));
  TerminalParserTest.assertParser(parser, "case 1 when 1 then 2 end",
      simpleCase(number(1), number(1), number(2), null));
}