1 files changed, 11 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/collections/Set-add-size.js b/js/src/jit-test/tests/collections/Set-add-size.js
new file mode 100644
index 0000000000..dfd131db67
--- /dev/null
+++ b/js/src/jit-test/tests/collections/Set-add-size.js
@@ -0,0 +1,11 @@
+// set.add(v) increments set.size iff the set did not already contain v.
+
+var s = new Set();
+for (var i = 0; i < 10; i++) {
+    assertEq(s.size, i);
+    s.add(i);
+}
+for (var i = 0; i < 10; i++) {
+    assertEq(s.size, 10);
+    s.add(i);
+}