1 files changed, 25 insertions, 0 deletions
diff --git a/js/src/tests/non262/ReadableStream/constructor-default.js b/js/src/tests/non262/ReadableStream/constructor-default.js
new file mode 100644
index 0000000000..bf95658801
--- /dev/null
+++ b/js/src/tests/non262/ReadableStream/constructor-default.js
@@ -0,0 +1,25 @@
+// The second argument to `new ReadableStream` defaults to `{}`, so it observes
+// properties hacked onto Object.prototype.
+
+let log = [];
+
+Object.defineProperty(Object.prototype, "size", {
+    configurable: true,
+    get() {
+        log.push("size");
+        log.push(this);
+        return undefined;
+    }
+});
+Object.prototype.highWaterMark = 1337;
+
+let s = new ReadableStream({
+    start(controller) {
+        log.push("start");
+        log.push(controller.desiredSize);
+    }
+});
+assertDeepEq(log, ["size", {}, "start", 1337]);
+
+if (typeof reportCompare == "function")
+    reportCompare(0, 0);