diff --git a/backend/src/tests/test-JIM.test.ts b/backend/src/tests/test-JIM.test.ts
new file mode 100644
index 0000000..5f5ebaa
--- /dev/null
+++ b/backend/src/tests/test-JIM.test.ts
@@ -0,0 +1,164 @@
+import { addCandidate } from '../application/services/candidateService';
+import { validateCandidateData } from '../application/validator';
+import { Candidate } from '../domain/models/Candidate';
+import { Education } from '../domain/models/Education';
+import { Resume } from '../domain/models/Resume';
+import { WorkExperience } from '../domain/models/WorkExperience';
+
+// Mocks
+jest.mock('../domain/models/Candidate');
+jest.mock('../domain/models/Education');
+jest.mock('../domain/models/WorkExperience');
+jest.mock('../domain/models/Resume');
+jest.mock('../application/validator');
+
+describe('Candidate Service', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  const mockCandidateData = {
+    name: 'John Doe',
+    email: 'john@example.com',
+    educations: [{ school: 'University A', degree: 'Bachelor' }],
+    workExperiences: [{ company: 'Company X', position: 'Developer' }],
+    cv: { fileName: 'resume.pdf' },
+  };
+
+  const mockSavedCandidate = { id: '123', ...mockCandidateData };
+
+    // Mock the Candidate constructor to initialize arrays
+    (Candidate as unknown as jest.Mock).mockImplementation(() => {
+      return {
+        ...mockCandidateData,
+        education: [],
+        workExperience: [],
+        resumes: [],
+        save: jest.fn().mockResolvedValue(mockSavedCandidate),
+      };
+    });
+
+  jest.spyOn(Candidate.prototype, 'save').mockImplementation(() =>
+    Promise.resolve({
+      id: 1,
+      firstName: 'John',
+      lastName: 'Doe',
+      email: 'john.doe@example.com',
+      phone: null,
+      address: null
+    })
+  );
+
+  jest.spyOn(Education.prototype, 'save').mockResolvedValue({
+    id: 1,
+    institution: 'Institution Name',
+    title: 'Title',
+    startDate: new Date(),
+    endDate: null,
+    candidateId: 1
+  });
+
+  jest.spyOn(WorkExperience.prototype, 'save').mockResolvedValue({
+    id: 1,
+    startDate: new Date(),
+    endDate: null,
+    candidateId: 1,
+    company: 'Company Name',
+    position: 'Position',
+    description: 'Description'
+  });
+
+  jest.spyOn(Resume.prototype, 'save').mockResolvedValue(
+    new Resume({
+      id: 1,
+      candidateId: 1,
+      filePath: "/test/path",
+      fileType: ".pdf",
+      uploadDate: new Date()
+    })
+  );
+
+  test('addCandidate should create a new candidate with all associated data', async () => {
+    const result = await addCandidate(mockCandidateData);
+
+    expect(validateCandidateData).toHaveBeenCalledWith(mockCandidateData);
+    expect(Candidate).toHaveBeenCalledWith(mockCandidateData);
+    expect(Education).toHaveBeenCalledWith(mockCandidateData.educations[0]);
+    expect(WorkExperience).toHaveBeenCalledWith(
+      mockCandidateData.workExperiences[0],
+    );
+    expect(Resume).toHaveBeenCalledWith(mockCandidateData.cv);
+    expect(result).toEqual(mockSavedCandidate);
+  });
+
+  test('addCandidate should handle candidate without education', async () => {
+    const candidateWithoutEducation = {
+      ...mockCandidateData,
+      educations: undefined,
+    };
+    const mockSavedCandidateWithoutEducation = { id: '123', ...candidateWithoutEducation };
+    (Candidate.prototype.save as jest.Mock).mockResolvedValue(
+      mockSavedCandidateWithoutEducation,
+    );
+
+    await addCandidate(candidateWithoutEducation);
+
+    expect(Education.prototype.save).not.toHaveBeenCalled();
+  });
+
+  test('addCandidate should handle candidate without work experience', async () => {
+    const candidateWithoutWorkExperience = {
+      ...mockCandidateData,
+      workExperiences: undefined,
+    };
+    const mockSavedCandidateWithoutWorkExperience = { id: '123', ...candidateWithoutWorkExperience };
+    (Candidate.prototype.save as jest.Mock).mockResolvedValue(
+      mockSavedCandidateWithoutWorkExperience,
+    );
+
+    await addCandidate(candidateWithoutWorkExperience);
+
+    expect(WorkExperience.prototype.save).not.toHaveBeenCalled();
+  });
+
+  test('addCandidate should handle candidate without CV', async () => {
+    const candidateWithoutCV = { ...mockCandidateData, cv: undefined };
+    const mockSavedCandidateWithoutCV = { id: '123', ...candidateWithoutCV };
+    (Candidate.prototype.save as jest.Mock).mockResolvedValue(
+      mockSavedCandidateWithoutCV,
+    );
+
+    await addCandidate(candidateWithoutCV);
+
+    expect(Resume.prototype.save).not.toHaveBeenCalled();
+  });
+
+  test('addCandidate should throw an error for invalid candidate data', async () => {
+    (validateCandidateData as jest.Mock).mockImplementation(() => {
+      throw new Error('Invalid candidate data');
+    });
+
+    await expect(addCandidate(mockCandidateData)).rejects.toThrow(
+      'Invalid candidate data',
+    );
+  });
+
+  test('addCandidate should throw an error for duplicate email', async () => {
+    (Candidate.prototype.save as jest.Mock).mockRejectedValue({
+      code: 'P2002',
+    });
+
+    await expect(addCandidate(mockCandidateData)).rejects.toThrow(
+      'Error: Invalid candidate data',
+    );
+  });
+
+  test('addCandidate should throw an error for other database errors', async () => {
+    const dbError = new Error('Database connection failed');
+    (Candidate.prototype.save as jest.Mock).mockRejectedValue(dbError);
+
+    await expect(addCandidate(mockCandidateData)).rejects.toThrow(
+      'Error: Invalid candidate data',
+    );
+  });
+});
diff --git a/prompts/JIM-prompts.md b/prompts/JIM-prompts.md
new file mode 100644
index 0000000..c056ee3
--- /dev/null
+++ b/prompts/JIM-prompts.md
@@ -0,0 +1,11 @@
+### Using copilot in VSCode
+
+# Prompt 1
+
+You're an expert software developer specialized in Unit test with Jest and Typescript. Analize the code in candidateService.ts and create a suite test to cover all the functionality of addCandidate function. In case of need some mocks, create them Create happy and bad paths for everything in a new file
+
+# Prompt 2
+
+After run the tests most of them are failing because the following error Cannot read properties of undefined (reading 'push') Can you fix the file test-JIM.test.ts
+
+No more prompts but I fixed some other tests with the option in contextual menu "fix this line with Copilot"