Chapter 7. Mocking CDI beans

Procedure

1. Create the ExternalService in the src/main/java directory similar to the following example:

   package org.acme.quickstart;
   
   import javax.enterprise.context.ApplicationScoped;
   
   @ApplicationScoped
   public class ExternalService {
   
       public String service() {
           return "external";
       }
   
   }

2. Create a class UsesExternalService that uses ExternalService in the src/main/java directory:

   package org.acme.quickstart;
   
   import javax.enterprise.context.ApplicationScoped;
   import javax.inject.Inject;
   
   @ApplicationScoped
   public class UsesExternalService {
   
       @Inject
       ExternalService externalService;
   
       public String doSomething() {
           return externalService.service();
       }
   }

3. Create a test in the src/test/java directory similar to the following example:

   package org.acme.quickstart;
   
   import javax.inject.Inject;
   
   import io.quarkus.test.junit.QuarkusTest;
   import org.junit.jupiter.api.Assertions;
   import org.junit.jupiter.api.Test;
   
   @QuarkusTest
   class UsesExternalServiceTest {
   
       @Inject
       UsesExternalService usesExternalService;
   
       @Test
       public void testDoSomething() {
           Assertions.assertEquals("external", usesExternalService.doSomething());
       }
   }

4. Create the MockExternalService in the src/test/java that uses the @Alternative annotation:

   package org.acme.quickstart;
   
   import javax.annotation.Priority;
   import javax.enterprise.context.ApplicationScoped;
   import javax.enterprise.inject.Alternative;
   
   @Alternative
   @Priority(1)
   @ApplicationScoped
   public class MockExternalService extends ExternalService { 1
   
       @Override
       public String service() {
           return "mock";
       }
   }

   1

   The MockExternalService is injected wherever the ExternalService is being used. In this example, MockExternalService will be used in UsesExternalService.

   Note

   You can use the @Mock annotation instead of the @Alternative,@Priority(1) and @Dependent annotations.

   The following example shows how to create MockExternalService class that uses the @Mock annotation:

   import javax.enterprise.context.ApplicationScoped;
   
   import io.quarkus.test.Mock;
   
   @Mock
   @ApplicationScoped
   public class MockExternalService extends ExternalService {
   
       @Override
       public String service() {
           return "mock";
       }
   }

5. Change the asserted string from "external" to "mock" in the test:

   package org.acme.quickstart;
   
   import javax.inject.Inject;
   
   import io.quarkus.test.junit.QuarkusTest;
   import org.junit.jupiter.api.Assertions;
   import org.junit.jupiter.api.Test;
   
   @QuarkusTest
   class UsesExternalServiceTest {
   
       @Inject
       UsesExternalService usesExternalService;
   
       @Test
       public void testDoSomething() {
           Assertions.assertEquals("mock", usesExternalService.doSomething());
       }
   }