1 files changed, 75 insertions, 0 deletions
diff --git a/testing/web-platform/tests/resource-timing/resources/buffer-full-utilities.js b/testing/web-platform/tests/resource-timing/resources/buffer-full-utilities.js
new file mode 100644
index 0000000000..6cb1753b2e
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/buffer-full-utilities.js
@@ -0,0 +1,75 @@
+// This script relies on resources/resource-loaders.js. Include it before in order for the below
+// methods to work properly.
+
+// The resources used to trigger new entries.
+const scriptResources = [
+    'resources/empty.js',
+    'resources/empty_script.js',
+    'resources/empty.js?id'
+];
+
+const waitForNextTask = () => {
+    return new Promise(resolve => {
+        step_timeout(resolve, 0);
+    });
+};
+
+const clearBufferAndSetSize = size => {
+  performance.clearResourceTimings();
+  performance.setResourceTimingBufferSize(size);
+}
+
+const forceBufferFullEvent = async () => {
+  clearBufferAndSetSize(1);
+  return new Promise(async resolve => {
+    performance.addEventListener('resourcetimingbufferfull', resolve);
+    // Load 2 resources to ensure onresourcetimingbufferfull is fired.
+    // Load them in order in order to get the entries in that order!
+    await load.script(scriptResources[0]);
+    await load.script(scriptResources[1]);
+  });
+};
+
+const fillUpTheBufferWithSingleResource = async (src = scriptResources[0]) => {
+  clearBufferAndSetSize(1);
+  await load.script(src);
+};
+
+const fillUpTheBufferWithTwoResources = async () => {
+    clearBufferAndSetSize(2);
+    // Load them in order in order to get the entries in that order!
+    await load.script(scriptResources[0]);
+    await load.script(scriptResources[1]);
+};
+
+const addAssertUnreachedBufferFull = t => {
+  performance.addEventListener('resourcetimingbufferfull', t.step_func(() => {
+    assert_unreached("resourcetimingbufferfull should not fire")
+  }));
+};
+
+const checkEntries = numEntries => {
+  const entries = performance.getEntriesByType('resource');
+  assert_equals(entries.length, numEntries,
+      'Number of entries does not match the expected value.');
+  assert_true(entries[0].name.includes(scriptResources[0]),
+      scriptResources[0] + " is in the entries buffer");
+  if (entries.length > 1) {
+    assert_true(entries[1].name.includes(scriptResources[1]),
+        scriptResources[1] + " is in the entries buffer");
+  }
+  if (entries.length > 2) {
+    assert_true(entries[2].name.includes(scriptResources[2]),
+        scriptResources[2] + " is in the entries buffer");
+  }
+}
+
+const bufferFullFirePromise = new Promise(resolve => {
+  performance.addEventListener('resourcetimingbufferfull', async () => {
+    // Wait for the next task just to ensure that all bufferfull events have fired, and to ensure
+    // that the secondary buffer is copied (as this is an event, there may be microtask checkpoints
+    // right after running an event handler).
+    await waitForNextTask();
+    resolve();
+  });
+});