diff --git a/test/unit/core.ts b/test/unit/core.ts
index a201830..c53a873 100644
--- a/test/unit/core.ts
+++ b/test/unit/core.ts
@@ -87,19 +87,19 @@ describe("snabbdom", function () {
       assert.strictEqual(vnode.text, "I am a string");
     });
     it("can create vnode with String obj content", function() {
-      var vnode = h("a", new String("b"));
+      const vnode = h("a", new String("b"));
       assert.equal(vnode.text, "b");
     });
     it("can create vnode with props and String obj content", function() {
-      var vnode = h("a", {}, new String("b"));
+      const vnode = h("a", {}, new String("b"));
       assert.equal(vnode.text, "b");
     });
     it("can create vnode with array String obj content", function() {
-      var vnode = h("a", ["b", new String("c")]);
+      const vnode = h("a", ["b", new String("c")]);
       assert.equal(vnode.text, "bc");
     });
     it("can create vnode with Number obj content", function() {
-      var vnode = h("a", new Number(1));
+      const vnode = h("a", new Number(1));
       assert.equal(vnode.text, "1");
     });
     it("can create vnode with null props", function () {