test(selectText): restore firefox tests (#1829)

Author: pavelfeldman

test/elementhandle.spec.js

@@ -328,19 +328,29 @@ describe('ElementHandle.fill', function() {
 });
 
 describe('ElementHandle.selectText', function() {
-  it.fail(FFOX)('should select textarea', async({page, server}) => {
+  it('should select textarea', async({page, server}) => {
     await page.goto(server.PREFIX + '/input/textarea.html');
     const textarea = await page.$('textarea');
     await textarea.evaluate(textarea => textarea.value = 'some value');
     await textarea.selectText();
-    expect(await page.evaluate(() => window.getSelection().toString())).toBe('some value');
+    if (FFOX) {
+      expect(await textarea.evaluate(el => el.selectionStart)).toBe(0);
+      expect(await textarea.evaluate(el => el.selectionEnd)).toBe(10);
+    } else {
+      expect(await page.evaluate(() => window.getSelection().toString())).toBe('some value');
+    }
   });
-  it.fail(FFOX)('should select input', async({page, server}) => {
+  it('should select input', async({page, server}) => {
     await page.goto(server.PREFIX + '/input/textarea.html');
     const input = await page.$('input');
     await input.evaluate(input => input.value = 'some value');
     await input.selectText();
-    expect(await page.evaluate(() => window.getSelection().toString())).toBe('some value');
+    if (FFOX) {
+      expect(await input.evaluate(el => el.selectionStart)).toBe(0);
+      expect(await input.evaluate(el => el.selectionEnd)).toBe(10);
+    } else {
+      expect(await page.evaluate(() => window.getSelection().toString())).toBe('some value');
+    }
   });
   it('should select plain div', async({page, server}) => {
     await page.goto(server.PREFIX + '/input/textarea.html');