chromium/third_party/blink/web_tests/external/wpt/xhr/formdata/append-formelement.html

<!doctype html>
<meta charset="utf-8">
<title>FormData.append (with form element)
</title>
<link rel="help" href="https://xhr.spec.whatwg.org/#dom-formdata-append">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<form id="form"></form>
<script>
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        fd.append('key', 'value1');
        assert_equals(fd.get('key'), "value1");
    }, 'testFormDataAppendToForm1');
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        fd.append('key', 'value2');
        fd.append('key', 'value1');
        assert_equals(fd.get('key'), "value2");
    }, 'testFormDataAppendToForm2');
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        fd.append('key', undefined);
        assert_equals(fd.get('key'), "undefined");
    }, 'testFormDataAppendToFormUndefined1');
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        fd.append('key', undefined);
        fd.append('key', 'value1');
        assert_equals(fd.get('key'), "undefined");
    }, 'testFormDataAppendToFormUndefined2');
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        fd.append('key', null);
        assert_equals(fd.get('key'), "null");
    }, 'testFormDataAppendToFormNull1');
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        fd.append('key', null);
        fd.append('key', 'value1');
        assert_equals(fd.get('key'), "null");
    }, 'testFormDataAppendToFormNull2');
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        assert_throws_js(TypeError, () => {fd.append('name', "string", 'filename')});
    }, 'testFormDataAppendToFormString');
    test(function() {
        var fd = new FormData(document.getElementById("form"));
        assert_throws_js(TypeError, () => {fd.append('name', new URLSearchParams(), 'filename')});
    }, 'testFormDataAppendToFormWrongPlatformObject');
</script>