add test for legacyNativeRender to accept only one argument

src/legacyNativeRender.js

@@ -3,4 +3,4 @@ import { newNativeRenderManager } from './nativeRenderManager';
 window.pbNativeTag = (window.pbNativeTag || {});
 const nativeRenderManager = newNativeRenderManager(window);
 
-window.pbNativeTag.renderNativeAd = nativeRenderManager.renderNativeAd;
+window.pbNativeTag.renderNativeAd = (args) => nativeRenderManager.renderNativeAd.call(document, args);

test/spec/legacyNativeRender_spec.js

@@ -0,0 +1,21 @@
+import '../../src/legacyNativeRender';
+
+describe('legacyNativeRender', () => {
+
+    after(() => {
+        delete window.pbNativeTag;
+    })
+    it('should accept only one argument', () => {
+        expect(window.pbNativeTag.renderNativeAd).to.exist;
+        //expect exactly one argument by this function
+        expect(window.pbNativeTag.renderNativeAd.length).to.equal(1);
+
+        // try to call this function with two arguments and see it throw
+        const renderNativeAdWithTwoArguments = window.pbNativeTag.renderNativeAd.bind(this, document, {
+            pubUrl: 'http://prebidjs.com',
+            adId: 'abc123'
+        })
+        expect(renderNativeAdWithTwoArguments).to.throw();
+
+    })
+})

test/spec/nativeRender_spec.js

@@ -0,0 +1,23 @@
+import '../../src/nativeRender';
+
+describe('nativeRender', () => {
+
+    after(() => {
+        delete window.ucTag;
+    })
+
+    it('should accept 2 arguments', () => {
+        expect(window.ucTag.renderAd).to.exist;
+        //expect exactly two arguments by this function
+        expect(window.ucTag.renderAd.length).to.equal(2);
+
+        // this function with two arguments and see it NOT throwing
+        const renderAd = window.ucTag.renderAd.bind(this, document, {
+            pubUrl: 'http://prebidjs.com',
+            adId: 'abc123',
+            replaceAllAssets: true
+        })
+        expect(renderAd).to.not.throw();
+
+    })
+})