Rewrite e2e tests with await/async

e2e/contents/zoom.test.js

@@ -7,64 +7,44 @@ describe("zoom test", () => {
   let targetWindow;
   let targetTab;
 
-  before(() => {
-    return windows.create(CLIENT_URL).then((win) => {
-      targetWindow = win;
-    });
+  before(async () => {
+    targetWindow = await windows.create(CLIENT_URL);
   });
 
-  after(() => {
-    return windows.remove(targetWindow.id);
+  after(async () => {
+    await windows.remove(targetWindow.id);
   });
 
-  beforeEach(() => {
-    return tabs.create(targetWindow.id, CLIENT_URL).then((tab) => {
-      targetTab = tab;
-    });
+  beforeEach(async () => {
+    targetTab = await tabs.create(targetWindow.id, CLIENT_URL);
   });
 
-  it('zooms-in by zi', () => {
-    let before;
-    return tabs.getZoom(targetTab.id).then((zoom) => {
-      before = zoom;
-      return keys.press(targetTab.id, 'z');
-    }).then(() => {
-      return keys.press(targetTab.id, 'i');
-    }).then(() => {
-      return tabs.getZoom(targetTab.id);
-    }).then((actual) => {
-      expect(actual).to.be.greaterThan(before);
-    });
+  it('zooms-in by zi', async () => {
+    let before = await tabs.getZoom(targetTab.id);
+    await keys.press(targetTab.id, 'z');
+    await keys.press(targetTab.id, 'i');
+
+    let actual = await tabs.getZoom(targetTab.id);
+    expect(actual).to.be.greaterThan(before);
   });
 
-  it('zooms-in by zo', () => {
-    let before;
-    return tabs.getZoom(targetTab.id).then((zoom) => {
-      before = zoom;
-      return keys.press(targetTab.id, 'z');
-    }).then(() => {
-      return keys.press(targetTab.id, 'o');
-    }).then(() => {
-      return tabs.getZoom(targetTab.id);
-    }).then((actual) => {
-      expect(actual).to.be.lessThan(before);
-    });
+  it('zooms-in by zo', async () => {
+    let before = await tabs.getZoom(targetTab.id);
+    await keys.press(targetTab.id, 'z');
+    await keys.press(targetTab.id, 'o');
+
+    let actual = await tabs.getZoom(targetTab.id);
+    expect(actual).to.be.lessThan(before);
   });
 
-  it('zooms-in by zz', () => {
-    let before;
-    tabs.setZoom(targetTab.id, 1.5).then(() => {
-      return tabs.getZoom(targetTab.id);
-    }).then((zoom) => {
-      before = zoom;
-      return keys.press(targetTab.id, 'z');
-    }).then(() => {
-      return keys.press(targetTab.id, 'z');
-    }).then(() => {
-      return tabs.getZoom(targetTab.id);
-    }).then((actual) => {
-      expect(actual).to.be.lessThan(before);
-      expect(actual).to.be.be(1);
-    });
+  it('zooms-in by zz', async () => {
+    await tabs.setZoom(targetTab.id, 1.5);
+    let before = await tabs.getZoom(targetTab.id);
+    await keys.press(targetTab.id, 'z');
+    await keys.press(targetTab.id, 'z');
+
+    let actual = await tabs.getZoom(targetTab.id);
+    expect(actual).to.be.lessThan(before);
+    expect(actual).to.equal(1);
   });
 });