Augment iframe lazyload tests for srcdoc

This PR augments the existing iframe lazyload test for srcdoc lazyload support. Chrome currently does not implement this. The test accompanies the spec change made at: whatwg/html#5579. I am TBR'ing this because sclittle@ already reviewed this at #24361, but doesn't have the permissions to submit an "authoritative" review over there. TBR=sclittle@chromium.org Bug: 1101170 Change-Id: I5c5790c5d2eca3efbb01c5470e2267f2265858f6
web-platform-tests · Jul 1, 2020 · 5ef5346 · 5ef5346
1 parent 17f0e36
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diff --git a/common/square.png b/common/square.png
diff --git a/html/semantics/embedded-content/the-iframe-element/iframe-loading-lazy.tentative.html b/html/semantics/embedded-content/the-iframe-element/iframe-loading-lazy.tentative.html
@@ -2,52 +2,81 @@
 <head>
   <title>Iframes with loading='lazy' load when in the viewport</title>
   <link rel="author" title="Scott Little" href="mailto:sclittle@chromium.org">
-  <link rel="help" href="https://github.com/scott-little/lazyload">
+  <link rel="author" title="Dom Farolino" href="mailto:dom@chromium.org">
+  <link rel="help" href="https://github.com/whatwg/html/pull/5579">
   <script src="/resources/testharness.js"></script>
   <script src="/resources/testharnessreport.js"></script>
 </head>
 
 <script>
-  const t = async_test("Test that iframes with loading='lazy' load once they " +
-                       "enter the viewport.");
+  const t_in_viewport =
+    async_test('In-viewport iframes load eagerly');
+  const t_in_viewport_srcdoc=
+    async_test('In-viewport srcdoc iframes load eagerly');
+  const t_below_viewport =
+    async_test('Below-viewport iframes load lazily');
+  const t_below_viewport_srcdoc =
+    async_test('Below-viewport srcdoc iframes load lazily');
 
   let has_window_loaded = false;
-  let has_in_viewport_loaded = false;
 
-  const in_viewport_iframe_onload = t.step_func(() => {
-    assert_false(has_in_viewport_loaded,
-                 "The in_viewport element should load only once.");
-    has_in_viewport_loaded = true;
+  const in_viewport_iframe_onload = t_in_viewport.step_func_done(() => {
+    assert_false(has_window_loaded,
+      "The in_viewport iframe should not block the load event");
   });
 
-  window.addEventListener("load", t.step_func(() => {
-    assert_true(has_in_viewport_loaded,
-                "The in_viewport element should have loaded before " +
-                "window.load().");
+  const in_viewport_srcdoc_iframe_onload = t_in_viewport_srcdoc.step_func_done(() => {
     assert_false(has_window_loaded,
-                 "The window.load() event should only fire once.");
+      "The in_viewport srcdoc iframe should not block the load event");
+  });
+
+  window.addEventListener("load", () => {
     has_window_loaded = true;
-    document.getElementById("below_viewport").scrollIntoView();
-  }));
+    document.getElementById("below_viewport_srcdoc").scrollIntoView();
+  });
+
+  const below_viewport_iframe_onload = t_below_viewport.step_func_done(() => {
+    assert_true(has_window_loaded,
+                "The window.load() event should have fired before " +
+                "the below-viewport iframe loads");
+  });
 
-  const below_viewport_iframe_onload = t.step_func_done(() => {
+  // Must make this accessible to the srcdoc iframe's body.
+  window.below_viewport_srcdoc_iframe_subresource_onload = t_below_viewport_srcdoc.step_func(() => {
     assert_true(has_window_loaded,
                 "The window.load() event should have fired before " +
-                "below_viewport loaded.");
+                "the below-viewport srcdoc iframe's subresource loads");
+  });
+
+  const below_viewport_srcdoc_iframe_onload = t_below_viewport_srcdoc.step_func_done(() => {
+    assert_true(has_window_loaded,
+                "The window.load() event should have fired before " +
+                "the below-viewport srcdoc iframe loads");
   });
 </script>
 
 <body>
   <iframe id="in_viewport" src="resources/subframe.html?in-viewport"
           loading="lazy" width="200px" height="100px"
           onload="in_viewport_iframe_onload();"></iframe>
-  <div style="height:1000vh;"></div>
+  <iframe id="in_viewport_srcdoc"
+          srcdoc="<body><img src='/common/square.png?in-viewport'></body>"
+          loading="lazy" width="200px" height="100px"
+          onload="in_viewport_srcdoc_iframe_onload();"></iframe>
+
+  <div style="height:2000vh;"></div>
   <iframe id="below_viewport" src="resources/subframe.html?below-viewport"
           loading="lazy" width="200px" height="100px"
           onload="below_viewport_iframe_onload();"></iframe>
+  <iframe id="below_viewport_srcdoc"
+          srcdoc="<body><img src='/common/square.png?below-viewport'
+                  onload='parent.below_viewport_srcdoc_iframe_subresource_onload();'></body>"
+          loading="lazy" width="200px" height="100px"
+          onload="below_viewport_srcdoc_iframe_onload();"></iframe>
+
 
   <!-- This async script loads very slowly in order to ensure that, if the
-       below_viewport element has started loading, it has a chance to finish
+       below_viewport* elements have started loading, it has a chance to finish
        loading before window.load() happens, so that the test will dependably
        fail in that case instead of potentially passing depending on how long
        different resource fetches take. -->