Micronaut Test

In this tutorial, you'll learn about Fix Micronaut Test Not Loading Context. We cover key concepts, practical examples, and best practices.

The Problem

Micronaut tests fail with application context not loading or beans not found.

Quick Fix

Use @MicronautTest

Wrong:

// No test annotation
public class ProductServiceTest { }

Output:

Context not loaded

Right:

@MicronautTest
public class ProductServiceTest {
    @Inject
    private ProductService service;
}

Output:

Context loaded

Use @MockBean for mocks

Wrong:

@Inject
private ProductRepository repo; // Real bean

Output:

No mock

Right:

@MockBean(ProductRepository.class)
private ProductRepository repo; // Mocked

Output:

Mock injected

Configure test properties

Wrong:

# No test config
micronaut.application.name=test-app

Output:

Default config

Right:

# application-test.yml
micronaut:
  application:
    name: test-app
  server:
    port: -1

Output:

Test environment configured

Prevention

• Use @MicronautTest annotation on test classes
• Use @MockBean to replace beans with mocks
• Use test-specific application-test.yml

Common Mistakes with test

1. Using return to exit a function early instead of wrapping a pure value in the monad
2. Mixing let bindings with <- bindings in do notation, producing type errors
3. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors

These mistakes appear frequently in real-world MICRONAUT code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

This quick fix is part of the DodaTech Spring & JVM ecosystem series. Built by the developers of Doda Browser, DodaZIP, and Durga Antivirus Pro.