1 files changed, 85 insertions, 0 deletions
diff --git a/testing/web-platform/tests/content-security-policy/support/prefetch-helper.js b/testing/web-platform/tests/content-security-policy/support/prefetch-helper.js
new file mode 100644
index 0000000000..c0c0be9157
--- /dev/null
+++ b/testing/web-platform/tests/content-security-policy/support/prefetch-helper.js
@@ -0,0 +1,85 @@
+setup(_ => {
+  assert_implements_optional(
+    document.createElement('link').relList.supports('prefetch'),
+    "Browser supports prefetch.");
+  assert_implements_optional(
+    "PerformanceResourceTiming" in window,
+    "Browser supports performance APIs.");
+});
+
+function assert_resource_not_downloaded(test, url) {
+  // CSP failures generate resource timing entries, so let's make sure that
+  // download sizes are 0.
+  const entries = performance.getEntriesByName(url, 'resource');
+  for (const entry of entries) {
+    assert_equals(entry.transferSize, 0, 'transferSize');
+    assert_equals(entry.encodedBodySize, 0, 'encodedBodySize');
+    assert_equals(entry.decodedBodySize, 0, 'decodedBodySize');
+  }
+}
+
+function assert_link_prefetches(test, link) {
+  assert_no_csp_event_for_url(test, link.href);
+
+  link.onerror = test.unreached_func('onerror should not fire.');
+
+  // Test is finished when either the `load` event fires, or we get a performance
+  // entry showing that the resource loaded successfully.
+  link.onload = test.step_func(test.step_func_done());
+  waitUntilResourceDownloaded(link.href).then(test.step_func_done());
+
+  document.head.appendChild(link);
+}
+
+function assert_link_does_not_prefetch(test, link) {
+  let cspEvent = false;
+  let errorEvent = false;
+
+  waitUntilCSPEventForURL(test, link.href)
+      .then(test.step_func(e => {
+        cspEvent = true;
+        assert_equals(e.violatedDirective, "prefetch-src");
+        assert_equals(e.effectiveDirective, "prefetch-src");
+
+        if (errorEvent)
+          test.done();
+      }));
+
+  link.onerror = test.step_func(e => {
+    errorEvent = true;
+    if (cspEvent)
+      test.done();
+  });
+  link.onload = test.unreached_func('onload should not fire.');
+
+  document.head.appendChild(link);
+}
+
+async function try_to_prefetch(href, test) {
+  const url = new URL(href, location.href);
+  url.searchParams.set(
+      'pipe',
+      '|header(Cache-Control, max-age=604800)' +
+          '|header(Access-Control-Allow-Origin, *)' +
+          '|header(Timing-Allow-Origin, *)');
+  url.searchParams.set('uuid', token());
+
+  const link = document.createElement('link');
+  link.rel = 'prefetch';
+  link.href = url.toString();
+  link.crossOrigin = 'anonymous';
+  test.add_cleanup(() => link.remove());
+
+  const didPrefetch = new Promise(resolve => {
+    const observer = new PerformanceObserver(list => {
+      const entries = list.getEntriesByName(link.href);
+      if (entries.length) {
+        resolve(entries[0]);
+      }
+    });
+    observer.observe({entryTypes: ['resource']})
+  });
+  document.head.appendChild(link);
+  const entry = await didPrefetch;
+  return entry.requestStart > 0 && entry.decodedBodySize > 0;
+}