1 files changed, 27 insertions, 0 deletions
diff --git a/js/src/tests/ecma_6/RegExp/exec-lastIndex-negative.js b/js/src/tests/ecma_6/RegExp/exec-lastIndex-negative.js
new file mode 100644
index 000000000..18eb2ab9d
--- /dev/null
+++ b/js/src/tests/ecma_6/RegExp/exec-lastIndex-negative.js
@@ -0,0 +1,27 @@
+var BUGNUMBER = 1207922;
+var summary = "negative lastIndex should be treated as 0.";
+
+print(BUGNUMBER + ": " + summary);
+
+var pattern = /abc/gi;
+var string = 'AbcaBcabC';
+
+var indices = [
+    -1,
+    -Math.pow(2,32),
+    -(Math.pow(2,32) + 1),
+    -Math.pow(2,32) * 2,
+    -Math.pow(2,40),
+    -Number.MAX_VALUE,
+];
+for (var index of indices) {
+  pattern.lastIndex = index;
+  var result = pattern.exec(string);
+  assertEq(result.index, 0);
+  assertEq(result.length, 1);
+  assertEq(result[0], "Abc");
+  assertEq(pattern.lastIndex, 3);
+}
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);