1 files changed, 55 insertions, 0 deletions
diff --git a/dom/html/test/test_bug643051.html b/dom/html/test/test_bug643051.html
new file mode 100644
index 0000000000..5719d1d2db
--- /dev/null
+++ b/dom/html/test/test_bug643051.html
@@ -0,0 +1,55 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=643051
+-->
+<head>
+  <title>Test for Bug 643051</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=643051">Mozilla Bug 643051</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+SpecialPowers.pushPrefEnv({
+  "set": [
+    // Bug 1617611: Fix all the tests broken by "cookies SameSite=lax by default"
+    ["network.cookie.sameSite.laxByDefault", false],
+  ]
+}, () => {
+  /** Test for Bug 643051 **/
+  document.cookie = "a=; expires=Thu, 01-Jan-1970 00:00:01 GMT";  // clear cookie
+  document.cookie = "a2=; expires=Thu, 01-Jan-1970 00:00:01 GMT";  // clear cookie
+  document.cookie = "a3=; expires=Thu, 01-Jan-1970 00:00:01 GMT";  // clear cookie
+
+  // single cookie, should work
+  document.cookie = "a=bar";
+  is(document.cookie, "a=bar", "Can't read stored cookie!");
+
+  document.cookie = "a2=bar\na3=bar";
+  is(document.cookie, "a=bar; a2=bar", "Wrong cookie value");
+
+  document.cookie = "a2=baz; a3=bar";
+  is(document.cookie, "a=bar; a2=baz", "Wrong cookie value");
+
+  // clear cookies again to avoid affecting other tests
+  document.cookie = "a=; expires=Thu, 01-Jan-1970 00:00:01 GMT";
+  document.cookie = "a2=; expires=Thu, 01-Jan-1970 00:00:01 GMT";
+  document.cookie = "a3=; expires=Thu, 01-Jan-1970 00:00:01 GMT";
+
+  SpecialPowers.clearUserPref("network.cookie.sameSite.laxByDefault");
+  SimpleTest.finish();
+});
+
+</script>
+</pre>
+</body>
+</html>