ConsoleCaptor

Install library with:

Install with maven

<dependency>
    <groupId>io.github.hakky54</groupId>
    <artifactId>consolecaptor</artifactId>
    <version>1.0.4</version>
    <scope>test</scope>
</dependency>

Install with Gradle

testImplementation 'io.github.hakky54:consolecaptor:1.0.4'

Install with Scala SBT

libraryDependencies += "io.github.hakky54" % "consolecaptor" % "1.0.4" % Test

Install with Apache Ivy

<dependency org="io.github.hakky54" name="consolecaptor" rev="1.0.4" />

Table of contents

1. Introduction
   • Advantages
   • Tested Java versions
2. Usage
   • Capture Console Output
   • Reuse ConsoleCaptor for multiple tests
3. Contributing
4. License

Introduction

Hey, hello there 👋 Welcome. I hope you will like this library ❤️

ConsoleCaptor is a library which will enable you to easily capture the output of the console for unit testing purposes.

Do you want to capture logs? Please have a look at LogCaptor.

Advantages

• No mocking required
• No custom JUnit extension required
• Plug & play
• Zero transitive dependencies

Tested Java versions

• Java 8
• Java 11+

See the unit test ConsoleCaptorShould for all the scenario's.

Usage

Capture console output

public class FooService {

    public void sayHello() {
        System.out.println("Keyboard not responding. Press any key to continue...");
        System.err.println("Congratulations, you are pregnant!");
    }

}

Unit test:

import static org.assertj.core.api.Assertions.assertThat;

import nl.altindag.console.ConsoleCaptor;
import org.junit.jupiter.api.Test;

public class FooServiceShould {

    @Test
    public void captureStandardAndErrorOutput() {
        ConsoleCaptor consoleCaptor = new ConsoleCaptor();

        FooService fooService = new FooService();
        fooService.sayHello();

        assertThat(consoleCaptor.getStandardOutput()).contains("Keyboard not responding. Press any key to continue...");
        assertThat(consoleCaptor.getErrorOutput()).contains("Congratulations, you are pregnant!");
        
        consoleCaptor.close();
    }
}

Initialize ConsoleCaptor once and reuse it during multiple tests with clearOutput() method within the afterEach method:

import nl.altindag.console.ConsoleCaptor;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeAll;

public class FooServiceShould {

    private static ConsoleCaptor consoleCaptor;
    
    @BeforeAll
    public static void setupConsoleCaptor() {
        consoleCaptor = new ConsoleCaptor();
    }

    @AfterEach
    public void clearOutput() {
        consoleCaptor.clearOutput();
    }
    
    @AfterAll
    public static void tearDown() {
        consoleCaptor.close();
    }

    @Test
    public void captureStandardOutput() {
        FooService service = new FooService();
        service.sayHello();

        assertThat(consoleCaptor.getStandardOutput()).contains("Keyboard not responding. Press any key to continue...");
    }

    @Test
    public void captureErrorOutput() {
        FooService service = new FooService();
        service.sayHello();

        assertThat(consoleCaptor.getErrorOutput()).contains("Congratulations, you are pregnant!");
    }

}

Customise ConsoleCapture

It is possible to adjust the console captures behaviour with the builder pattern as shown below

ConsoleCaptor consoleCaptor = ConsoleCaptor.builder()
        .allowEmptyLines(true)
        .allowTrimmingWhiteSpace(false)
        .withEncoding(StandardCharsets.UTF_16)
        .build();

Contributing

There are plenty of ways to contribute to this project:

• Give it a star
• Make a donation through GitHub or open collective
• Join the Gitter room and leave a feedback or help with answering users questions
• Submit a PR

License