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@src/main/java/com/mydeveloperplanet/myaicodeprojectplanet/controller/CustomersController.java

Write a unit test for this code using JUnit. 
Use WebMvcTest. 
Use MockMvc. 
Use AssertJ assertions.

Add the test in this repository

1. Yes                                                                                                                                                                                                        
2. Yes, and approve all file operations for the rest of the running session                                                                                                                                     3. No, and tell Copilot what to do differently (Esc to stop)

Excellent! ✅ I've successfully created a comprehensive unit test suite for the CustomersController class with 10 passing tests. Here's what was included:

  Test Coverage

  The test file (CustomersControllerTest.java) uses:

   - @WebMvcTest annotation for controller testing
   - MockMvc for making HTTP requests and asserting responses
   - @MockitoBean for mocking the CustomerService
   - AssertJ assertions for validating results

  Tests Created

   1. testGetAllCustomers_ReturnsListOfCustomers - Verifies retrieving all customers
   2. testGetAllCustomers_ReturnsEmptyList - Tests empty list scenario
   3. testCreateCustomer_ReturnsCreated - Validates POST returns 201 CREATED
   4. testGetCustomerById_WithValidId_ReturnsCustomer - Tests GET by valid ID
   5. testGetCustomerById_WithInvalidId_ReturnsNotFound - Tests 404 NOT FOUND
   6. testUpdateCustomer_WithValidId_ReturnsOk - Validates PUT request
   7. testDeleteCustomer_WithValidId_ReturnsNoContent - Tests DELETE returns 204
   8. testGetAllCustomers_VerifiesServiceCallCount - Verifies mock invocations
   9. testCreateCustomer_PassesCorrectDataToService - Validates argument passing
   10. testUpdateCustomer_PassesCorrectIdAndData - Validates update parameters

  The tests are located at: 
  /home/<project directory>/myaicodeprojectplanet/src/test/java/com/mydeveloperplanet/myaicodeprojectplanet/controller/CustomersControllerTest.java

  All tests passed successfully! ✅

package com.mydeveloperplanet.myaicodeprojectplanet.controller;

import com.mydeveloperplanet.myaicodeprojectplanet.model.Customer;
import com.mydeveloperplanet.myaicodeprojectplanet.service.CustomerService;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.test.context.bean.override.mockito.MockitoBean;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;

import static org.assertj.core.api.Assertions.*;
import static org.mockito.ArgumentMatchers.*;
import static org.mockito.Mockito.*;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

@WebMvcTest(CustomersController.class)
class CustomersControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @MockitoBean
    private CustomerService customerService;

    @Autowired
    private ObjectMapper objectMapper;

    private Customer testCustomer;
    private com.mydeveloperplanet.myaicodeprojectplanet.openapi.model.Customer openAPICustomer;

    @BeforeEach
    void setUp() {
        testCustomer = new Customer(1L, "John", "Doe");
        openAPICustomer = new com.mydeveloperplanet.myaicodeprojectplanet.openapi.model.Customer();
        openAPICustomer.setId(1L);
        openAPICustomer.setFirstName("John");
        openAPICustomer.setLastName("Doe");
    }

    @Test
    void testGetAllCustomers_ReturnsListOfCustomers() throws Exception {
        // Arrange
        Customer customer2 = new Customer(2L, "Jane", "Smith");
        List<Customer> customers = Arrays.asList(testCustomer, customer2);
        when(customerService.getAllCustomers()).thenReturn(customers);

        // Act & Assert
        mockMvc.perform(get("/customers")
                .contentType(MediaType.APPLICATION_JSON))
                .andExpect(status().isOk())
                .andExpect(content().contentType(MediaType.APPLICATION_JSON))
                .andDo(result -> {
                    String responseBody = result.getResponse().getContentAsString();
                    assertThat(responseBody).contains("John", "Doe", "Jane", "Smith");
                });

        verify(customerService, times(1)).getAllCustomers();
    }

    @Test
    void testGetAllCustomers_ReturnsEmptyList() throws Exception {
        // Arrange
        when(customerService.getAllCustomers()).thenReturn(Arrays.asList());

        // Act & Assert
        mockMvc.perform(get("/customers")
                .contentType(MediaType.APPLICATION_JSON))
                .andExpect(status().isOk())
                .andExpect(content().json("[]"));

        verify(customerService, times(1)).getAllCustomers();
    }

    @Test
    void testCreateCustomer_ReturnsCreated() throws Exception {
        // Arrange
        when(customerService.createCustomer(any(Customer.class))).thenReturn(testCustomer);

        // Act & Assert
        mockMvc.perform(post("/customers")
                .contentType(MediaType.APPLICATION_JSON)
                .content(objectMapper.writeValueAsString(openAPICustomer)))
                .andExpect(status().isCreated());

        verify(customerService, times(1)).createCustomer(any(Customer.class));
    }

    @Test
    void testGetCustomerById_WithValidId_ReturnsCustomer() throws Exception {
        // Arrange
        when(customerService.getCustomerById(1L)).thenReturn(Optional.of(testCustomer));

        // Act & Assert
        mockMvc.perform(get("/customers/1")
                .contentType(MediaType.APPLICATION_JSON))
                .andExpect(status().isOk())
                .andExpect(content().contentType(MediaType.APPLICATION_JSON))
                .andDo(result -> {
                    String responseBody = result.getResponse().getContentAsString();
                    assertThat(responseBody).contains("John", "Doe", "1");
                });

        verify(customerService, times(1)).getCustomerById(1L);
    }

    @Test
    void testGetCustomerById_WithInvalidId_ReturnsNotFound() throws Exception {
        // Arrange
        when(customerService.getCustomerById(999L)).thenReturn(Optional.empty());

        // Act & Assert
        mockMvc.perform(get("/customers/999")
                .contentType(MediaType.APPLICATION_JSON))
                .andExpect(status().isNotFound());

        verify(customerService, times(1)).getCustomerById(999L);
    }

    @Test
    void testUpdateCustomer_WithValidId_ReturnsOk() throws Exception {
        // Arrange
        Customer updatedCustomer = new Customer(1L, "John", "Updated");
        when(customerService.updateCustomer(eq(1L), any(Customer.class))).thenReturn(updatedCustomer);

        com.mydeveloperplanet.myaicodeprojectplanet.openapi.model.Customer updateRequest =
                new com.mydeveloperplanet.myaicodeprojectplanet.openapi.model.Customer();
        updateRequest.setId(1L);
        updateRequest.setFirstName("John");
        updateRequest.setLastName("Updated");

        // Act & Assert
        mockMvc.perform(put("/customers/1")
                .contentType(MediaType.APPLICATION_JSON)
                .content(objectMapper.writeValueAsString(updateRequest)))
                .andExpect(status().isOk());

        verify(customerService, times(1)).updateCustomer(eq(1L), any(Customer.class));
    }

    @Test
    void testDeleteCustomer_WithValidId_ReturnsNoContent() throws Exception {
        // Arrange
        doNothing().when(customerService).deleteCustomer(1L);

        // Act & Assert
        mockMvc.perform(delete("/customers/1")
                .contentType(MediaType.APPLICATION_JSON))
                .andExpect(status().isNoContent());

        verify(customerService, times(1)).deleteCustomer(1L);
    }

    @Test
    void testGetAllCustomers_VerifiesServiceCallCount() throws Exception {
        // Arrange
        when(customerService.getAllCustomers()).thenReturn(Arrays.asList(testCustomer));

        // Act
        mockMvc.perform(get("/customers"));
        mockMvc.perform(get("/customers"));

        // Assert
        verify(customerService, times(2)).getAllCustomers();
    }

    @Test
    void testCreateCustomer_PassesCorrectDataToService() throws Exception {
        // Arrange
        when(customerService.createCustomer(any(Customer.class))).thenReturn(testCustomer);

        // Act & Assert
        mockMvc.perform(post("/customers")
                .contentType(MediaType.APPLICATION_JSON)
                .content(objectMapper.writeValueAsString(openAPICustomer)))
                .andExpect(status().isCreated());

        verify(customerService, times(1)).createCustomer(argThat(customer ->
                customer.getFirstName().equals("John") &&
                customer.getLastName().equals("Doe")
        ));
    }

    @Test
    void testUpdateCustomer_PassesCorrectIdAndData() throws Exception {
        // Arrange
        Customer updatedCustomer = new Customer(1L, "John", "Updated");
        when(customerService.updateCustomer(eq(1L), any(Customer.class))).thenReturn(updatedCustomer);

        com.mydeveloperplanet.myaicodeprojectplanet.openapi.model.Customer updateRequest =
                new com.mydeveloperplanet.myaicodeprojectplanet.openapi.model.Customer();
        updateRequest.setFirstName("John");
        updateRequest.setLastName("Updated");

        // Act & Assert
        mockMvc.perform(put("/customers/1")
                .contentType(MediaType.APPLICATION_JSON)
                .content(objectMapper.writeValueAsString(updateRequest)))
                .andExpect(status().isOk());

        verify(customerService, times(1)).updateCustomer(eq(1L), argThat(customer ->
                customer.getFirstName().equals("John") &&
                customer.getLastName().equals("Updated")
        ));
    }

}

# Copilot Instructions for MyAiCodeProjectPlanet

## Quick Start

This is a **Spring Boot 3.5.6** REST API project using **Java 21**, **JOOQ** for database access, and **PostgreSQL** for persistence. It includes OpenAPI schema-driven development.

## Build, Test, and Run

### Build the project
```bash
mvn clean install
```

### Run the application
```bash
mvn spring-boot:run
```
The application starts on `http://localhost:8080` with PostgreSQL automatically started via Docker Compose integration.

### Run all tests
```bash
mvn test
```

### Run a single test
```bash
mvn test -Dtest=CustomersControllerTest
```

### Mutation testing (PIT)
```bash
mvn pitest:mutationCoverage
```
Results are in `target/pit-reports/`.

### Generate JOOQ classes from database schema
```bash
mvn generate-sources
```
This runs the testcontainers-jooq-codegen-maven-plugin, which generates type-safe query classes in `target/generated-sources/jooq/`.

## Architecture

### Layered Structure
The application follows a **classic 3-tier architecture**:

- **Controller Layer** (`controller/`): REST endpoints implementing OpenAPI-generated interfaces
- **Service Layer** (`service/`): Business logic with `CustomerService` interface and `CustomerServiceImpl` implementation
- **Repository Layer** (`repository/`): Data access using JOOQ's DSL for type-safe queries
- **Model Layer** (`model/`): Domain objects (e.g., `Customer`)

### API-First Development
The API is defined in `src/main/resources/static/customers.yaml` (OpenAPI spec). The OpenAPI Maven plugin auto-generates service interfaces in `com.mydeveloperplanet.myaicodeprojectplanet.openapi`. Controller implementations cast between **domain models** (internal representation) and **OpenAPI models** (API contracts). This separation isolates API changes from business logic.

### Database Access Pattern
- Uses **JOOQ** for type-safe SQL queries (not JPA/Hibernate)
- Generated JOOQ classes from schema located in `com.mydeveloperplanet.myaicodeprojectplanet.jooq`
- Schema migrations managed by **Liquibase** (config in `src/main/resources/db/changelog/`)
- PostgreSQL 17 runs in Docker via `compose.yaml` with Spring Boot's docker-compose support

### Key Dependencies
- `spring-boot-starter-web`: REST endpoints and Spring MVC
- `spring-boot-starter-jooq`: JOOQ integration
- `spring-boot-docker-compose`: Auto-starts PostgreSQL container
- `testcontainers-jooq-codegen-maven-plugin`: Generates JOOQ classes during build
- `openapi-generator-maven-plugin`: Generates API interfaces from YAML spec
- `pitest-maven`: Mutation testing for code quality validation

## Key Conventions

### Model Conversion Pattern
Controllers convert between two model layers:
- **Domain models** (`Customer` in `model/`): Core business objects
- **OpenAPI models** (`com.mydeveloperplanet.myaicodeprojectplanet.openapi.model.Customer`): API-specific DTOs

This is done explicitly in controller methods using `convertToOpenAPIModel()` and `convertToDomainModel()` helpers. Maintain this separation when adding new endpoints.

### Service Layer Usage
- All business logic resides in service implementations
- Controllers inject services via `@Autowired` (not constructor injection yet)
- Services return domain models; controllers handle API model conversion

### Repository Method Signatures
Repository methods return domain models, not JOOQ records. Internal mapping is done via `convertToCustomer()`. This keeps JOOQ types hidden from upper layers.

### Testing
- Unit tests are in `src/test/java/` mirroring source structure
- Use `@SpringBootTest` for integration tests requiring Spring context
- Consider Testcontainers for database integration tests (already a dependency)

## Common Tasks

### Adding a New Endpoint
1. Update `src/main/resources/static/customers.yaml` with the new operation
2. Run `mvn generate-sources` to regenerate OpenAPI interfaces
3. Implement the new method in `CustomersController`
4. Add business logic to `CustomerServiceImpl`
5. Extend `CustomerRepository` if new database queries are needed
6. Write tests in `CustomersControllerTest`

### Adding a New Domain Entity
1. Create domain model class in `model/`
2. Add schema changes to Liquibase changelog (if database entity)
3. Create repository class in `repository/` for data access
4. Create service interface and implementation in `service/`
5. Create controller in `controller/`
6. Add OpenAPI spec to the YAML file and regenerate

### Debugging Locally
- PostgreSQL logs are visible in console output when running `mvn spring-boot:run`
- JOOQ-generated SQL is logged at DEBUG level; enable in `application.properties` if needed
- Use `mvn test -X` for Maven debug output

## Notes

- **Java 21 records** may be used where appropriate (modern codebase target)
- **PIT mutation testing** is configured; commit confidence is validated via mutation coverage
- **Liquibase** handles schema versioning—database changes go in changelog files, not direct SQL
- The `.mvn/` directory contains Maven wrapper; `./mvnw` works on Unix/macOS, `.\mvnw.cmd` on Windows

{
  "mcpServers": {
    "context7": {
      "type": "local",
      "command": "npx",
      "args": ["-y", "@upstash/context7-mcp"],
      "tools": ["*"],
      "env": {}
    },
    "jooq": {
      "type": "http",
      "url": "https://jooq-mcp.martinelli.ch/mcp",
      "tools": ["*"]
    },
    "javadoc": {
      "type": "http",
      "url": "https://www.javadocs.dev/mcp",
      "tools": ["*"]
    }
  }
}

No user-configured servers.

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     ~/.copilot/mcp-config.json