Cookie Store API: empty string path defaulting

For whatwg/cookiestore#283.

Author: annevk

cookiestore/cookieStore_set_path.https.window.js

@@ -0,0 +1,23 @@
+// META: title=Cookie Store API: set()'s path option
+// META: script=/resources/testdriver.js
+// META: script=/resources/testdriver-vendor.js
+
+promise_test(async testCase => {
+  const currentUrl = new URL(self.location.href);
+  const currentPath = currentUrl.pathname;
+  const currentDirectory = currentPath.substr(0, currentPath.lastIndexOf('/'));
+
+  await cookieStore.set({ name: 'cookie-name', value: 'cookie-value', path: '' });
+  testCase.add_cleanup(async () => {
+    await cookieStore.delete({ name: 'cookie-name', path: currentDirectory });
+  });
+
+  const internalCookie = await test_driver.get_named_cookie('cookie-name');
+  assert_equals(internalCookie.path, currentDirectory);
+}, 'CookieListItem - cookieStore.set with empty string path defaults to current URL');
+
+promise_test(async testCase => {
+  const currentUrl = new URL(self.location.href);
+  const currentPath = currentUrl.pathname;
+  return promise_rejects_js(testCase, TypeError, cookieStore.set({ name: '__host-cookie-name', value: 'cookie-value', path: '' }));
+}, 'CookieListItem - cookieStore.set with empty string path defaults to current URL with __host- prefix');