diff --git a/test/util.js b/test/util.js
new file mode 100644
index 0000000000..40e7b647ed
--- /dev/null
+++ b/test/util.js
@@ -0,0 +1,27 @@
+var assert = require("assert");
+var util   = require("../lib/6to5/util");
+
+suite("util", function () {
+  test("duplicate mutator map", function () {
+    var map = {
+      test: {
+        get: {}
+      }
+    };
+
+    assert.throws(function () {
+      util.pushMutatorMap(map, "test", "get", {});
+    }, /a get already exists for this property/);
+  });
+
+  test("can compile", function () {
+    assert.ok(util.canCompile("test.js"));
+    assert.ok(util.canCompile("/test.js"));
+    assert.ok(util.canCompile("/scripts/test.js"));
+
+    assert.ok(!util.canCompile("test"));
+    assert.ok(!util.canCompile("test.css"));
+    assert.ok(!util.canCompile("/test.css"));
+    assert.ok(!util.canCompile("/scripts/test.css"));
+  });
+});