1 files changed, 52 insertions, 0 deletions
diff --git a/testing/web-platform/tests/xhr/response-data-progress.htm b/testing/web-platform/tests/xhr/response-data-progress.htm
new file mode 100644
index 0000000000..78e749429f
--- /dev/null
+++ b/testing/web-platform/tests/xhr/response-data-progress.htm
@@ -0,0 +1,52 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="utf-8">
+    <title>XMLHttpRequest: progress events grow response body size</title>
+    <meta name="timeout" content="long">
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <link rel="help" href="https://xhr.spec.whatwg.org/#the-send()-method" data-tested-assertations="following::a[contains(@href,'#make-progress-notifications')]/.. following::a[contains(@href,'#make-progress-notifications')]/../following:p[1]" />
+    <link rel="help" href="https://xhr.spec.whatwg.org/#make-progress-notifications" data-tested-assertations=".." />
+    <link rel="help" href="https://xhr.spec.whatwg.org/#handler-xhr-onprogress" data-tested-assertations="/../.." />
+    <link rel="help" href="https://xhr.spec.whatwg.org/#event-xhr-progress" data-tested-assertations="/../.." />
+</head>
+
+<div id="log"></div>
+
+<script>
+
+function doTest(test, expectedLengthComputable, expectedTotal, url) {
+    var client = new XMLHttpRequest();
+    var lastSize = 0;
+
+    client.onprogress = test.step_func(function(e) {
+        assert_equals(e.total, expectedTotal);
+        assert_equals(e.lengthComputable, expectedLengthComputable);
+
+        var currentSize = client.responseText.length;
+
+        if (lastSize > 0 && currentSize > lastSize) {
+            // growth from a positive size to bigger!
+            test.done();
+        }
+
+        lastSize = currentSize;
+    });
+
+    client.onreadystatechange = test.step_func(function() {
+        if (client.readyState === 4) {
+            assert_unreached("onprogress not called multiple times, or response body did not grow.");
+        }
+    });
+
+    client.open("GET", url);
+    client.send(null);
+    return client;
+}
+
+async_test(function () { doTest(this, false, 0, "resources/trickle.py?count=6&delay=150"); },
+           document.title + ', unknown content-length');
+async_test(function () { doTest(this, true, 78, "resources/trickle.py?count=6&delay=150&specifylength=1"); },
+           document.title + ', known content-length');
+</script>