third_party/web_platform_tests/FileAPI/reading-data-section/filereader_file-manual.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>FileAPI Test: filereader_file</title>
    <link rel="author" title="Intel" href="http://www.intel.com">
    <link rel="help" href="http://dev.w3.org/2006/webapi/FileAPI/#FileReader-interface">
    <link rel="help" href="http://dev.w3.org/2006/webapi/FileAPI/#file">
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
  </head>
  <body>
    <div>
      <p>Test step:</p>
      <ol>
        <li>Download <a href="support/blue-100x100.png">blue-100x100.png</a> to local.</li>
        <li>Select the local file (blue-100x100.png) to run the test.</li>
      </ol>
    </div>

    <form name="uploadData">
      <input type="file" id="fileChooser">
    </form>

    <div id="log"></div>
    <script>
      var fileInput = document.querySelector('#fileChooser');
      var reader = new FileReader();

      //readType: 1-> ArrayBuffer, 2-> Text, 3-> DataURL
      var readType = 1;

      setup({
        explicit_done: true,
        explicit_timeout: true,
      });

      on_event(fileInput, "change", function(evt) {
        reader.readAsArrayBuffer(fileInput.files[0]);
      });

      on_event(reader, "load", function(evt) {
        if (readType == 1) {
          test(function() {
            assert_true(reader.result instanceof ArrayBuffer, "The result is instanceof ArrayBuffer");
          }, "Check if the readAsArrayBuffer works");

          readType++;
          reader.readAsText(fileInput.files[0]);
        } else if (readType == 2) {
          test(function() {
            assert_equals(typeof reader.result, "string", "The result is typeof string");
          }, "Check if the readAsText works");

          readType++;
          reader.readAsDataURL(fileInput.files[0]);
        } else if (readType == 3) {
          test(function() {
            assert_equals(typeof reader.result, "string", "The result is typeof string");
            assert_equals(reader.result.indexOf("data"), 0, "The result starts with 'data'");
            assert_true(reader.result.indexOf("base64") > 0, "The result contains 'base64'");
          }, "Check if the readAsDataURL works");

          done();
        }
      });
    </script>
  </body>
</html>