nodeify - fix test

test/unit/nodeify-test.js

@@ -18,14 +18,13 @@ describe('nodeify', function () {
     })
   })
 
-  it('should throw if the last argument is not a function', function (done) {
+  it('should allow the last argument to not be a function', function (done) {
     const nodified = nodeify(obj.promiseFunc, obj)
     try {
       nodified('baz')
-      done(new Error('should have thrown if the last argument is not a function'))
-    } catch (err) {
-      assert.equal(err.message, 'callback is not a function')
       done()
+    } catch (err) {
+      done(new Error('should not have thrown if the last argument is not a function'))
     }
   })
 })