Solving the @Autowired Null Issue in Spring Boot Test with @ConditionalOnProperty

Learn how to effectively manage the `-Autowired` dependency in your Spring Boot tests, even with conditional properties. This guide simplifies the process for developers facing null issues in their unit tests.
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Addressing the -Autowired Null Issue in Spring Boot Tests

When working with Spring Boot, especially with conditional configurations using -ConditionalOnProperty, developers may encounter challenges during unit testing. One such issue arises when an -Autowired member in a service class remains null, contrary to expectations. In this post, we'll explore a sample scenario to better understand the problem and provide a straightforward solution.

The Problem

Consider the following service class that has a conditional property:

[[See Video to Reveal this Text or Code Snippet]]

In this class, the someObject dependency is injected if the property name is set to true. However, during unit testing, many developers have found that this property condition prevents someObject from being autowired correctly, resulting in a null reference.

Here's how the test might look:

[[See Video to Reveal this Text or Code Snippet]]

In this setup, the intention is to mock SomeObject and get an instance of MyClass. However, someObject is null in the test case even when the mock is supposed to be injected.

The Solution

Fortunately, there's a simpler way to handle this issue without resorting to static methods. Here’s how you can adjust your test:

Step-by-Step Breakdown

Import Annotations: Make sure you have the required Spring testing annotations in place.

Use -SpringBootTest: This annotation allows you to define properties directly used in the context.

Autowired Instance: Directly autowire MyClass and SomeObject in your test class.

Here’s the revised test class:

[[See Video to Reveal this Text or Code Snippet]]

Key Updates

Removed the static getMyClass method: This simplifies the code and makes it easier for Spring to manage the lifecycle of your beans.

Added -SpringBootTest(properties = "name=true"): This activates the conditional logic in your service class, ensuring someObject will be properly autowired.

Regular field injection of MyClass: This allows for cleaner and more intuitive testing.

Conclusion

By modifying your test setup as shown, you can efficiently manage the -Autowired behavior in conjunction with -ConditionalOnProperty. This not only resolves the null issue but also makes your test class more straightforward and aligned with Spring's best practices.

With this knowledge, you can confidently write unit tests for your Spring Boot applications without worrying about conditional property declarations that might hinder dependency injection.

Feel free to adapt this solution to your testing scenarios and improve your development efficiency!