DartPad Test #1 - Happy path

index.html

<!-- Copyright 2011 the Dart project authors. All rights reserved.
     Use of this source code is governed by a BSD-style license
     that can be found in the LICENSE file. -->

<h2>This is some HTML, just in case.</h2
>

main.dart

String stringify(int x, int y) {
  // Return a formatted string here
}

styles.css

/* Copyright 2011 the Dart project authors. All rights reserved. */
/* Use of this source code is governed by a BSD-style license */
/* that can be found in the LICENSE file. */

/* Make it blue, so we can see the style is in use */
h2 {
  color: #00f;
}

test.dart

void main() {
  final str = stringify(2, 3); 
  if (str == '2 3') {
    _result(true);
  } else if (str == '23') {
    _result(false, ['Test failed. It looks like you forgot the space!']);
  } else if (str == null) {
    _result(false, ['Test failed. Did you forget to return a value?']);
  } else {
    _result(false, ['That\'s not quite right. Keep trying!']);
  }
}