diff --git a/xpcom/tests/unit/test_storagestream.js b/xpcom/tests/unit/test_storagestream.js
index 9d732640715..e954c746cfc 100644
--- a/xpcom/tests/unit/test_storagestream.js
+++ b/xpcom/tests/unit/test_storagestream.js
@@ -60,6 +60,21 @@ function test1()
 
   var out = ss.getOutputStream(0);
   var inp2 = ss.newInputStream(0);
+  do_check_eq(inp2.available(), 0);
+  do_check_true(inp2.isNonBlocking());
+
+  var sis =
+      Cc["@mozilla.org/scriptableinputstream;1"]
+        .createInstance(Ci.nsIScriptableInputStream);
+  sis.init(inp2);
+
+  var threw = false;
+  try {
+    sis.read(1);
+  } catch (ex if ex.result == Cr.NS_BASE_STREAM_WOULD_BLOCK) {
+    threw = true;
+  }
+  do_check_true(threw);
 }
 
 /**