org.springframework.boot.test.system

Class OutputCaptureExtension

java.lang.Object

org.springframework.boot.test.system.OutputCaptureExtension

All Implemented Interfaces:

org.junit.jupiter.api.extension.AfterAllCallback, org.junit.jupiter.api.extension.AfterEachCallback, org.junit.jupiter.api.extension.BeforeAllCallback, org.junit.jupiter.api.extension.BeforeEachCallback, org.junit.jupiter.api.extension.Extension, org.junit.jupiter.api.extension.ParameterResolver

public class OutputCaptureExtension
extends Object
implements org.junit.jupiter.api.extension.BeforeAllCallback, org.junit.jupiter.api.extension.AfterAllCallback, org.junit.jupiter.api.extension.BeforeEachCallback, org.junit.jupiter.api.extension.AfterEachCallback, org.junit.jupiter.api.extension.ParameterResolver

JUnit Jupiter @Extension to capture System.out and System.err. Can be registered for an entire test class or for an individual test method through @ExtendWith. This extension provides parameter resolution for a CapturedOutput instance which can be used to assert that the correct output was written.

To use with @ExtendWith, inject the CapturedOutput as an argument to your test class constructor, test method, or lifecycle methods:

 @ExtendWith(OutputCaptureExtension.class)
 class MyTest {

     @Test
     void test(CapturedOutput output) {
         System.out.println("ok");
         assertThat(output).contains("ok");
         System.err.println("error");
     }

     @AfterEach
     void after(CapturedOutput output) {
         assertThat(output.getOut()).contains("ok");
         assertThat(output.getErr()).contains("error");
     }

 }
 

To ensure that their output can be captured, Java Util Logging (JUL) and Log4j2 require additional configuration.

To reliably capture output from Java Util Logging, reset its configuration after each test:

 @AfterEach
 void reset() throws Exception {
     LogManager.getLogManager().readConfiguration();
 }
 

To reliably capture output from Log4j2, set the follow attribute of the console appender to true:

 <Appenders>
     <Console name="Console" target="SYSTEM_OUT" follow="true">
         ...
     </Console>
  </Appenders>
 

Since:

2.2.0

Author:

Madhura Bhave, Phillip Webb, Andy Wilkinson, Sam Brannen

See Also:

CapturedOutput

Method Summary

Modifier and Type	Method and Description
void	afterAll(org.junit.jupiter.api.extension.ExtensionContext context)
void	afterEach(org.junit.jupiter.api.extension.ExtensionContext context)
void	beforeAll(org.junit.jupiter.api.extension.ExtensionContext context)
void	beforeEach(org.junit.jupiter.api.extension.ExtensionContext context)
Object	resolveParameter(org.junit.jupiter.api.extension.ParameterContext parameterContext, org.junit.jupiter.api.extension.ExtensionContext extensionContext)
boolean	supportsParameter(org.junit.jupiter.api.extension.ParameterContext parameterContext, org.junit.jupiter.api.extension.ExtensionContext extensionContext)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

beforeAll

public void beforeAll(org.junit.jupiter.api.extension.ExtensionContext context)
               throws Exception

Specified by:

beforeAll in interface org.junit.jupiter.api.extension.BeforeAllCallback

Throws:

Exception

afterAll

public void afterAll(org.junit.jupiter.api.extension.ExtensionContext context)
              throws Exception

Specified by:

afterAll in interface org.junit.jupiter.api.extension.AfterAllCallback

Throws:

Exception

beforeEach

public void beforeEach(org.junit.jupiter.api.extension.ExtensionContext context)
                throws Exception

Specified by:

beforeEach in interface org.junit.jupiter.api.extension.BeforeEachCallback

Throws:

Exception

afterEach

public void afterEach(org.junit.jupiter.api.extension.ExtensionContext context)
               throws Exception

Specified by:

afterEach in interface org.junit.jupiter.api.extension.AfterEachCallback

Throws:

Exception

supportsParameter

public boolean supportsParameter(org.junit.jupiter.api.extension.ParameterContext parameterContext,
                                 org.junit.jupiter.api.extension.ExtensionContext extensionContext)
                          throws org.junit.jupiter.api.extension.ParameterResolutionException

Specified by:

supportsParameter in interface org.junit.jupiter.api.extension.ParameterResolver

Throws:

org.junit.jupiter.api.extension.ParameterResolutionException

resolveParameter

public Object resolveParameter(org.junit.jupiter.api.extension.ParameterContext parameterContext,
                               org.junit.jupiter.api.extension.ExtensionContext extensionContext)

Specified by:

resolveParameter in interface org.junit.jupiter.api.extension.ParameterResolver