How to use the mwparserfromhell.nodes.Argument function in mwparserfromhell

def test_insert(self):
        """test Wikicode.insert()"""
        code = parse("Have a {{template}} and a [[page|link]]")
        code.insert(1, "{{{argument}}}")
        self.assertEqual(
            "Have a {{{argument}}}{{template}} and a [[page|link]]", code)
        self.assertIsInstance(code.get(1), Argument)
        code.insert(2, None)
        self.assertEqual(
            "Have a {{{argument}}}{{template}} and a [[page|link]]", code)
        code.insert(-3, Text("foo"))
        self.assertEqual(
            "Have a {{{argument}}}foo{{template}} and a [[page|link]]", code)

        code2 = parse("{{foo}}{{bar}}{{baz}}")
        code2.insert(1, "abc{{def}}ghi[[jk]]")
        self.assertEqual("{{foo}}abc{{def}}ghi[[jk]]{{bar}}{{baz}}", code2)
        self.assertEqual(["{{foo}}", "abc", "{{def}}", "ghi", "[[jk]]",
                          "{{bar}}", "{{baz}}"], code2.nodes)

        code3 = parse("{{foo}}bar")
        code3.insert(1000, "[[baz]]")
        code3.insert(-1000, "derp")

tokens.TemplateClose(), tokens.TemplateClose(),
                tokens.WikilinkOpen(), tokens.Text(text="f"),
                tokens.WikilinkSeparator(), tokens.ArgumentOpen(),
                tokens.Text(text="g"), tokens.ArgumentClose(),
                tokens.CommentStart(), tokens.Text(text="h"),
                tokens.CommentEnd(), tokens.WikilinkClose(),
                tokens.TemplateOpen(), tokens.Text(text="i"),
                tokens.TemplateParamSeparator(), tokens.Text(text="j"),
                tokens.TemplateParamEquals(), tokens.HTMLEntityStart(),
                tokens.Text(text="nbsp"), tokens.HTMLEntityEnd(),
                tokens.TemplateClose()]
        valid = wrap(
            [Template(wraptext("a"), params=[Parameter(wraptext("1"), wraptext(
            "b"), showkey=False), Parameter(wraptext("2"), wrap([Template(
            wraptext("c"), params=[Parameter(wraptext("1"), wrap([Wikilink(
            wraptext("d")), Argument(wraptext("e"))]), showkey=False)])]),
            showkey=False)]), Wikilink(wraptext("f"), wrap([Argument(wraptext(
            "g")), Comment("h")])), Template(wraptext("i"), params=[
            Parameter(wraptext("j"), wrap([HTMLEntity("nbsp",
            named=True)]))])])
        self.assertWikicodeEqual(valid, self.builder.build(test))

def test_argument(self):
        """tests for building Argument nodes"""
        tests = [
            ([tokens.ArgumentOpen(), tokens.Text(text="foobar"),
              tokens.ArgumentClose()],
             wrap([Argument(wraptext("foobar"))])),

            ([tokens.ArgumentOpen(), tokens.Text(text="spam"),
              tokens.Text(text="eggs"), tokens.ArgumentClose()],
             wrap([Argument(wraptext("spam", "eggs"))])),

            ([tokens.ArgumentOpen(), tokens.Text(text="foo"),
              tokens.ArgumentSeparator(), tokens.Text(text="bar"),
              tokens.ArgumentClose()],
             wrap([Argument(wraptext("foo"), wraptext("bar"))])),

            ([tokens.ArgumentOpen(), tokens.Text(text="foo"),
              tokens.Text(text="bar"), tokens.ArgumentSeparator(),
              tokens.Text(text="baz"), tokens.Text(text="biz"),
              tokens.ArgumentClose()],
             wrap([Argument(wraptext("foo", "bar"), wraptext("baz", "biz"))])),
        ]
        for test, valid in tests:
            self.assertWikicodeEqual(valid, self.builder.build(test))

def test_argument(self):
        """tests for building Argument nodes"""
        tests = [
            ([tokens.ArgumentOpen(), tokens.Text(text="foobar"),
              tokens.ArgumentClose()],
             wrap([Argument(wraptext("foobar"))])),

            ([tokens.ArgumentOpen(), tokens.Text(text="spam"),
              tokens.Text(text="eggs"), tokens.ArgumentClose()],
             wrap([Argument(wraptext("spam", "eggs"))])),

            ([tokens.ArgumentOpen(), tokens.Text(text="foo"),
              tokens.ArgumentSeparator(), tokens.Text(text="bar"),
              tokens.ArgumentClose()],
             wrap([Argument(wraptext("foo"), wraptext("bar"))])),

            ([tokens.ArgumentOpen(), tokens.Text(text="foo"),
              tokens.Text(text="bar"), tokens.ArgumentSeparator(),
              tokens.Text(text="baz"), tokens.Text(text="biz"),
              tokens.ArgumentClose()],
             wrap([Argument(wraptext("foo", "bar"), wraptext("baz", "biz"))])),
        ]

def test_children(self):
        """test Argument.__children__()"""
        node1 = Argument(wraptext("foobar"))
        node2 = Argument(wraptext("foo"), wrap([Text("bar"), Text("baz")]))
        gen1 = node1.__children__()
        gen2 = node2.__children__()
        self.assertIs(node1.name, next(gen1))
        self.assertIs(node2.name, next(gen2))
        self.assertIs(node2.default, next(gen2))
        self.assertRaises(StopIteration, next, gen1)
        self.assertRaises(StopIteration, next, gen2)

def test_showtree(self):
        """test Argument.__showtree__()"""
        output = []
        getter, marker = object(), object()
        get = lambda code: output.append((getter, code))
        mark = lambda: output.append(marker)
        node1 = Argument(wraptext("foobar"))
        node2 = Argument(wraptext("foo"), wraptext("bar"))
        node1.__showtree__(output.append, get, mark)
        node2.__showtree__(output.append, get, mark)
        valid = [
            "{{{", (getter, node1.name), "}}}", "{{{", (getter, node2.name),
            "    | ", marker, (getter, node2.default), "}}}"]
        self.assertEqual(valid, output)

def test_default(self):
        """test getter/setter for the default attribute"""
        default = wraptext("baz")
        node1 = Argument(wraptext("foobar"))
        node2 = Argument(wraptext("foobar"), default)
        self.assertIs(None, node1.default)
        self.assertIs(default, node2.default)
        node1.default = "buzz"
        node2.default = None
        self.assertWikicodeEqual(wraptext("buzz"), node1.default)
        self.assertIs(None, node2.default)

def test_default(self):
        """test getter/setter for the default attribute"""
        default = wraptext("baz")
        node1 = Argument(wraptext("foobar"))
        node2 = Argument(wraptext("foobar"), default)
        self.assertIs(None, node1.default)
        self.assertIs(default, node2.default)
        node1.default = "buzz"
        node2.default = None
        self.assertWikicodeEqual(wraptext("buzz"), node1.default)
        self.assertIs(None, node2.default)

def test_showtree(self):
        """test Argument.__showtree__()"""
        output = []
        getter, marker = object(), object()
        get = lambda code: output.append((getter, code))
        mark = lambda: output.append(marker)
        node1 = Argument(wraptext("foobar"))
        node2 = Argument(wraptext("foo"), wraptext("bar"))
        node1.__showtree__(output.append, get, mark)
        node2.__showtree__(output.append, get, mark)
        valid = [
            "{{{", (getter, node1.name), "}}}", "{{{", (getter, node2.name),
            "    | ", marker, (getter, node2.default), "}}}"]
        self.assertEqual(valid, output)

def _handle_argument(self, token):
        """Handle a case where an argument is at the head of the tokens."""
        name = None
        self._push()
        while self._tokens:
            token = self._tokens.pop()
            if isinstance(token, tokens.ArgumentSeparator):
                name = self._pop()
                self._push()
            elif isinstance(token, tokens.ArgumentClose):
                if name is not None:
                    return Argument(name, self._pop())
                return Argument(self._pop())
            else:
                self._write(self._handle_token(token))
        raise ParserError("_handle_argument() missed a close token")