Update

app/routes/library/details/books.js

@@ -1,8 +1,8 @@
 import Route from '@ember/routing/route';
-import {action} from '@ember/object';
+import { action } from '@ember/object';
 export default class LibraryDetailsBooksRoute extends Route {
-//     @action
-//     bubbled(){
-//         console.log('bubbled from book');
-//     }
+  //     @action
+  //     bubbled(){
+  //         console.log('bubbled from book');
+  //     }
 }

app/templates/library/details/books/book.hbs

@@ -1,6 +1,6 @@
 {{page-title "Book"}}
 
-<div align="center" class="book">
+<div align="center">
     <h3>{{this.model.name}}</h3>
     <h4><u>DESCRIPTION</u></h4>
     <p>Author : {{this.model.author}}</p>

app/templates/library/index.hbs

@@ -2,7 +2,7 @@
 <div align="center"> 
         <h1>Libraries</h1>
         {{#each this.model as |lib|}}
-        <div style="padding:10px">
+        <div style="padding:10px"  class="library">
             <LinkTo @route="library.details" @model={{lib.id}}>{{lib.name}}</LinkTo>
         </div>
         {{/each}}

tests/acceptance/book-test.js

@@ -1,11 +1,9 @@
 import { module, test } from 'qunit';
 import { visit, currentURL } from '@ember/test-helpers';
 import { setupApplicationTest } from 'my-app/tests/helpers';
-import { setupMirage } from 'ember-cli-mirage/test-support';
 
 module('Acceptance | book', function (hooks) {
   setupApplicationTest(hooks);
-  setupMirage(hooks);
 
   test('visiting /book', async function (assert) {
     await visit('/book');
@@ -14,15 +12,4 @@ module('Acceptance | book', function (hooks) {
 
     assert.strictEqual(currentURL(), '/book');
   });
-
-  test('mirage testing',async function (assert) {
-
-    this.server.createList('library', 3);
-    console.log(this.server.db);
-
-    await visit('/book');
-
-    // assert.dom('.book').exists();
-    assert.ok(true);
-  })
 });

tests/acceptance/library-test.js

@@ -0,0 +1,25 @@
+import { module, test } from 'qunit';
+import { visit, currentURL } from '@ember/test-helpers';
+import { setupApplicationTest } from 'my-app/tests/helpers';
+import { setupMirage } from 'ember-cli-mirage/test-support';
+module('Acceptance | library', function (hooks) {
+  setupApplicationTest(hooks);
+  setupMirage(hooks);
+
+
+  test('visiting /library', async function (assert) {
+    await visit('/library');
+
+    assert.strictEqual(currentURL(), '/library');
+  });
+
+  test('mirage testing', async function (assert) {
+    this.server.createList('library', 3);
+    console.log(this.server.db);
+
+    await visit('/library');
+
+    assert.dom('.library').exists({count:3});
+    assert.ok(true);
+  });
+});

tests/integration/components/nav-bar-test.js

@@ -1,4 +1,4 @@
-import { module, test ,skip} from 'qunit';
+import { module, test, skip } from 'qunit';
 import { setupRenderingTest } from 'my-app/tests/helpers';
 import { click, render } from '@ember/test-helpers';
 import { hbs } from 'ember-cli-htmlbars';
@@ -24,14 +24,13 @@ module('Integration | Component | nav-bar', function (hooks) {
     assert.dom().hasText('template block text');
   });
 
-  test('user interaction ', async function(assert) {
+  test('user interaction ', async function (assert) {
     await render(hbs`<NavBar/>`);
 
     // assert.dom('#numLibraryReq').hasAnyText('0');
-  
+
     await click('.buttonMode');
     // assert.dom('.buttonMode').hasText('dark');
     assert.dom('.buttonMode').hasText('light');
-
-  })
+  });
 });

tests/unit/controllers/library/details/read-book-test.js

@@ -1,6 +1,6 @@
 import { module, test } from 'qunit';
 import { setupTest } from 'my-app/tests/helpers';
-import {set} from '@ember/object';
+import { set } from '@ember/object';
 
 module('Unit | Controller | library/details/read-book', function (hooks) {
   setupTest(hooks);
@@ -12,16 +12,16 @@ module('Unit | Controller | library/details/read-book', function (hooks) {
   });
 
   test('checking getbook action', function (assert) {
-    let controller = this.owner.lookup("controller:library/details/read-book");
-    let router = this.owner.lookup("service:router");
+    let controller = this.owner.lookup('controller:library/details/read-book');
+    let router = this.owner.lookup('service:router');
 
-    set(controller,'name','priya');
-    set(controller,'email','priya@gmail.com');
-    set(controller,'router',router);
+    set(controller, 'name', 'priya');
+    set(controller, 'email', 'priya@gmail.com');
+    set(controller, 'router', router);
 
-    assert.equal(controller.name,'priya','name equal');
+    assert.equal(controller.name, 'priya', 'name equal');
     // controller.getBook();
     // controller.send('getBooK');
     // console.log(controller);
-  })
+  });
 });

tests/unit/models/book-test.js

@@ -2,7 +2,6 @@ import { module, test } from 'qunit';
 import { setupTest } from 'my-app/tests/helpers';
 import { get } from '@ember/object';
 
-
 module('Unit | Model | book', function (hooks) {
   setupTest(hooks);
 
@@ -13,13 +12,13 @@ module('Unit | Model | book', function (hooks) {
     assert.ok(model);
   });
 
-  test('testing relationships', function(assert){
-    let Book = this.owner.lookup("service:store").modelFor("book");
-    let library =get(Book,'relationshipsByName').get('library');
-    
+  test('testing relationships', function (assert) {
+    let Book = this.owner.lookup('service:store').modelFor('book');
+    let library = Book.relationshipsByName.get('library');
+
     // console.log(Book);
     // console.log(get(Book,'relationshipsByName'));
 
-    assert.equal(library.key,'library','has relationship library')
-  })
+    assert.equal(library.key, 'library', 'has relationship library');
+  });
 });