@Test
public void parsesFunctionCall() throws Exception {

  assertThat(parser.parse("foo()")).isEqualTo(new Function(new Identifier("foo")));
  assertThat(parser.parse("foo(bar)")).isEqualTo(new Function(new Identifier("foo"), new Identifier("bar")));
  assertThat(parser.parse("foo(bar,baz,qix)")).isEqualTo(new Function(new Identifier("foo"), new Identifier("bar"),
      new Identifier("baz"), new Identifier("qix")));
  assertThat(parser.parse("foo(bar,baz(qix))")).isEqualTo(new Function(new Identifier("foo"), new Identifier("bar"),
      new Function(new Identifier("baz"), new Identifier("qix"))));
}