1 files changed, 63 insertions, 0 deletions
diff --git a/testing/web-platform/tests/resource-timing/resources/connection-reuse-test.js b/testing/web-platform/tests/resource-timing/resources/connection-reuse-test.js
new file mode 100644
index 0000000000..453fbd3405
--- /dev/null
+++ b/testing/web-platform/tests/resource-timing/resources/connection-reuse-test.js
@@ -0,0 +1,63 @@
+// This script is loaded in HTTP and HTTPS contexts to validate
+// PerformanceResourceTiming entries' attributes when reusing connections.
+//
+// Note: to ensure that we reuse the connection to fetch multiple resources, we
+// use the same XMLHttpRequest object throughout an individual test. Although
+// it doesn't seem to be specified, each browser tested by WPT will reuse the
+// underlying TCP connection with this approach. Pre-establishing the XHR's
+// connection helps us to test connection reuse also in browsers that may key
+// their connections on the related request's credentials mode.
+
+const connection_reuse_test = (path, follow_on_assertions, test_label) => {
+  const {on_200, on_304} = follow_on_assertions;
+
+  // Make the first request before calling 'attribute_test' so that only the
+  // second request's PerformanceResourceTiming entry will be interrogated. We
+  // don't check the first request's PerformanceResourceTiming entry because
+  // that's not what this test is trying to validate.
+  const client = new XMLHttpRequest();
+  const identifier = Math.random();
+  path = `${path}?tag=${identifier}`;
+  client.open("GET", path, false);
+  client.send();
+
+  attribute_test(
+    async () => {
+      client.open("GET", path + "&same_resource=false", false);
+      client.send();
+
+      // We expect to get a 200 Ok response because we've requested a different
+      // resource than previous requests.
+      if (client.status != 200) {
+        throw new Error(`Got something other than a 200 response. ` +
+                        `client.status: ${client.status}`);
+      }
+    }, path, entry => {
+      invariants.assert_connection_reused(entry);
+      on_200(entry);
+    },
+    `PerformanceResrouceTiming entries need to conform to the spec when a ` +
+    `distinct resource is fetched over a persistent connection ` +
+    `(${test_label})`);
+
+  attribute_test(
+    async () => {
+      client.open("GET", path, false);
+      client.setRequestHeader("If-None-Match", identifier);
+      client.send();
+
+      // We expect to get a 304 Not Modified response because we've used a
+      // matching 'identifier' for the If-None-Match header.
+      if (client.status != 304) {
+        throw new Error(`Got something other than a 304 response. ` +
+                        `client.status: ${client.status}, response: ` +
+                        `'${client.responseText}'`);
+      }
+    }, path, entry => {
+      invariants.assert_connection_reused(entry);
+      on_304(entry);
+    },
+    `PerformanceResrouceTiming entries need to conform to the spec when the ` +
+    `resource is cache-revalidated over a persistent connection ` +
+    `(${test_label})`);
+}