test: add a few tests for null values (#3035)

Author: dgozman

src/network.ts

@@ -256,7 +256,7 @@ export class Response {
   }
 
   _requestFinished(error?: Error) {
-    this._finishedPromiseCallback.call(null, error);
+    this._finishedPromiseCallback.call(null, error || null);
   }
 
   url(): string {

test/elementhandle.jest.js

@@ -456,7 +456,9 @@ describe('ElementHandle convenience API', function() {
     await page.goto(`${server.PREFIX}/dom.html`);
     const handle = await page.$('#outer');
     expect(await handle.getAttribute('name')).toBe('value');
+    expect(await handle.getAttribute('foo')).toBe(null);
     expect(await page.getAttribute('#outer', 'name')).toBe('value');
+    expect(await page.getAttribute('#outer', 'foo')).toBe(null);
   });
   it('innerHTML should work', async({page, server}) => {
     await page.goto(`${server.PREFIX}/dom.html`);

test/emulation.jest.js

@@ -78,6 +78,12 @@ describe('BrowserContext({viewport})', function() {
     expect(await page.evaluate(() => 'ontouchstart' in window)).toBe(true);
     await context.close();
   });
+  it('should report null viewportSize when given null viewport', async({browser, server}) => {
+    const context = await browser.newContext({ viewport: null });
+    const page = await context.newPage();
+    expect(page.viewportSize()).toBe(null);
+    await context.close();
+  });
 });
 
 describe.skip(FFOX)('viewport.isMobile', () => {

test/navigation.jest.js

@@ -885,6 +885,8 @@ describe('Page.waitForLoadState', () => {
 
 describe('Page.goBack', function() {
   it('should work', async({page, server}) => {
+    expect(await page.goBack()).toBe(null);
+
     await page.goto(server.EMPTY_PAGE);
     await page.goto(server.PREFIX + '/grid.html');
 
@@ -1051,6 +1053,12 @@ describe('Page.reload', function() {
     await page.reload();
     expect(await page.evaluate(() => window._foo)).toBe(undefined);
   });
+  it('should work with data url', async({page, server}) => {
+    await page.goto('data:text/html,hello');
+    expect(await page.content()).toContain('hello');
+    expect(await page.reload()).toBe(null);
+    expect(await page.content()).toContain('hello');
+  });
 });
 
 describe('Click navigation', function() {

test/network.jest.js

@@ -345,13 +345,14 @@ describe('Network Events', function() {
     expect(await request.response()).toBeTruthy();
     expect(request.frame() === page.mainFrame()).toBe(true);
     expect(request.frame().url()).toBe(server.EMPTY_PAGE);
+    expect(request.failure()).toBe(null);
   });
   it('should fire events in proper order', async({page, server}) => {
     const events = [];
     page.on('request', request => events.push('request'));
     page.on('response', response => events.push('response'));
     const response = await page.goto(server.EMPTY_PAGE);
-    await response.finished();
+    expect(await response.finished()).toBe(null);
     events.push('requestfinished')
     expect(events).toEqual(['request', 'response', 'requestfinished']);
   });