1 files changed, 71 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..cb6fd4823f
--- /dev/null
+++ b/testing/web-platform/tests/content-security-policy/support/prefetch-helper.js
@@ -0,0 +1,71 @@
+setup(_ => {
+  assert_implements_optional(
+    document.createElement('link').relList.supports('prefetch'),
+    "Browser supports prefetch.");
+  assert_implements_optional(
+    "PerformanceResourceTiming" in window,
+    "Browser supports performance APIs.");
+});
+
+async function waitUntilResourceDownloaded(url) {
+  await new Promise((resolve, reject) => {
+    if (performance.getEntriesByName(url).length >= 1)
+      resolve();
+
+    let observer = new PerformanceObserver(list => {
+      list.getEntries().forEach(entry => {
+        if (entry.name == url) {
+          resolve();
+        }
+      });
+    });
+  });
+}
+
+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);
+}