Add e2e test case for history navigations

QA.md

@@ -27,7 +27,6 @@ The behaviors of the console are tested in [Console section](#consoles).
 
 #### Navigation
 
-- [ ] <kbd>H</kbd>, <kbd>L</kbd>: go back and forward in history
 - [ ] <kbd>[</kbd><kbd>[</kbd>, <kbd>]</kbd><kbd>]</kbd>: Open next/prev link in `<link>` tags.
 - [ ] <kbd>[</kbd><kbd>[</kbd>, <kbd>]</kbd><kbd>]</kbd>: find prev and next links and open it
 

e2e/contents/navigate.test.js

@@ -60,4 +60,30 @@ describe("navigate test", () => {
       expect(tab.url).to.be.equal(SERVER_URL + '/');
     });
   });
+
+  it('goes back and forward in history', () => {
+    let targetTab;
+    return tabs.create(targetWindow.id, SERVER_URL + '/#navigate').then((tab) => {
+      targetTab = tab;
+      return keys.press(targetTab.id, 'g');
+    }).then(() => {
+      return keys.press(targetTab.id, 'u');
+    }).then(() => {
+      return keys.press(targetTab.id, 'H', { shiftKey: true });
+    }).then(() => {
+      return new Promise(resolve => { setTimeout(() => resolve(), 2000) });
+    }).then(() => {
+      return tabs.get(targetTab.id);
+    }).then((tab) => {
+      expect(tab.url, 'go back in history').to.be.equal(SERVER_URL + '/#navigate');
+    }).then(() => {
+      return new Promise(resolve => { setTimeout(() => resolve(), 2000) });
+    }).then(() => {
+      return keys.press(targetTab.id, 'L', { shiftKey: true });
+    }).then(() => {
+      return tabs.get(targetTab.id);
+    }).then((tab) => {
+      expect(tab.url, 'go next in history').to.be.equal(SERVER_URL + '/#');
+    });
+  });
 });