Solution

cypress.config.js

@@ -2,7 +2,16 @@ const { defineConfig } = require('cypress');
 
 module.exports = defineConfig({
   e2e: {
+    baseUrl: 'https://demoqa.com/login',
     setupNodeEvents(on, config) {
+      on("task", {
+        generateUser() {
+          return {
+            password: '12345Qwert!',
+            username:'Kasia'
+          };
+        }
+      });
     }
   }
 });

cypress/e2e/bookStore.cy.js

@@ -1,11 +1,36 @@
 /// <reference types='cypress' />
 
 describe('Book Store app', () => {
-  before(() => {
-
-  });
+  const user = {
+    username: 'Kasia',
+    password: '12345Qwert!'
+  }  
+  const book = {
+    title: 'Speaking JavaScript',
+    author: 'Axel Rauschmayer',
+    publisher: `O'Reilly Media`
+  }
 
-  it('', () => {
+  before(() => {
+    cy.visit('https://demoqa.com/login')
+  })
 
-  });
+  it('should provide the ability to login', () => {
+    cy.get('#userName').type(user.username)
+    cy.get('#password').type(user.password)
+    cy.get('#login').click()
+    cy.url().should('not.include', 'https://demoqa.com/login')
+    cy.url().should('include', 'https://demoqa.com/profile')
+    cy.get('#userName-value').should('contain', user.username)
+  })
+
+  it('should provide the ability to search for the book', () => {
+    cy.login()
+    cy.visit('https://demoqa.com/books')
+    cy.contains('#item-2', 'Book Store').click()
+    cy.findByPlaceholder('Type to search').type(book.title)
+    cy.contains('[role="row"]', book.title)
+      .should('contain', book.author)
+      .and('contain', book.publisher)
+  })
 });

cypress/support/commands.js

@@ -23,3 +23,23 @@
 //
 // -- This will overwrite an existing command --
 // Cypress.Commands.overwrite('visit', (originalFn, url, options) => { ... })
+
+Cypress.Commands.add('login', (username = 'Kasia', password = '12345Qwert!') => {
+    cy.request({
+      method: 'POST',
+      url: 'https://demoqa.com/Account/v1/login',
+      body: {
+          "userName": username,
+          "password": password
+      }
+    }).then((response) => {
+      cy.setCookie('token', response.body.token)
+      cy.setCookie('userID', '3')
+      cy.setCookie('expires', response.body.expires)
+      cy.setCookie('userName', 'Kasia')
+    });
+  });
+
+Cypress.Commands.add('findByPlaceholder', (placeholder) => {
+    cy.get(`[placeholder="${placeholder}"]`)
+});

readme.md

@@ -13,9 +13,9 @@
 
 ## Task
 
-App for testing: [BookStore](https://demoqa.com/register)
+App for testing: [BookStore](https://demoqa.com/login)
 
-[Create](https://demoqa.com/register) your account **manually** before completing the task.  
+[Create](https://demoqa.com/login) your account **manually** before completing the task.  
 
 **Your task** is to check the following flow: