1 files changed, 74 insertions, 0 deletions
diff --git a/docshell/test/browser/browser_bug388121-2.js b/docshell/test/browser/browser_bug388121-2.js
new file mode 100644
index 0000000000..695ff1079c
--- /dev/null
+++ b/docshell/test/browser/browser_bug388121-2.js
@@ -0,0 +1,74 @@
+function test() {
+  waitForExplicitFinish();
+
+  var w;
+  var iteration = 1;
+  const uris = ["", "about:blank"];
+  var uri;
+  var origWgp;
+
+  function testLoad() {
+    let wgp = w.gBrowser.selectedBrowser.browsingContext.currentWindowGlobal;
+    if (wgp == origWgp) {
+      // Go back to polling
+      // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
+      setTimeout(testLoad, 10);
+      return;
+    }
+    var prin = wgp.documentPrincipal;
+    isnot(prin, null, "Loaded principal must not be null when adding " + uri);
+    isnot(
+      prin,
+      undefined,
+      "Loaded principal must not be undefined when loading " + uri
+    );
+    is(
+      prin.isSystemPrincipal,
+      false,
+      "Loaded principal must not be system when loading " + uri
+    );
+    w.close();
+
+    if (iteration == uris.length) {
+      finish();
+    } else {
+      ++iteration;
+      doTest();
+    }
+  }
+
+  function doTest() {
+    uri = uris[iteration - 1];
+    window.open(uri, "_blank", "width=10,height=10,noopener");
+    w = Services.wm.getMostRecentWindow("navigator:browser");
+    origWgp = w.gBrowser.selectedBrowser.browsingContext.currentWindowGlobal;
+    var prin = origWgp.documentPrincipal;
+    if (!uri) {
+      uri = undefined;
+    }
+    isnot(prin, null, "Forced principal must not be null when loading " + uri);
+    isnot(
+      prin,
+      undefined,
+      "Forced principal must not be undefined when loading " + uri
+    );
+    is(
+      prin.isSystemPrincipal,
+      false,
+      "Forced principal must not be system when loading " + uri
+    );
+    if (uri == undefined) {
+      // No actual load here, so just move along.
+      w.close();
+      ++iteration;
+      doTest();
+    } else {
+      // Need to poll, because load listeners on the content window won't
+      // survive the load.
+      // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
+      setTimeout(testLoad, 10);
+    }
+  }
+
+  doTest();
+}