Junit5: @TempDir: create temporary directory

@TempDir annotation is used to create a temporary directory.

 

Where to use @TempDir annotation?

Annotate a non-private field of type java.nio.file.Path or java.io.File with @TempDir or add a parameter of type java.nio.file.Path or java.io.File annotated with @TempDir to a lifecycle method or test method.

 

Example

public class TempDirectoryExtensionDemo {
    @TempDir
    Path sharedTempDir;

    .......
    .......
}

 

Find the below working application.

 

TempDirectoryExtensionDemo.java

package com.sample.app.extensions;

import static org.junit.jupiter.api.Assertions.assertEquals;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Path;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.io.TempDir;

public class TempDirectoryExtensionDemo {
    @TempDir
    static Path sharedTempDir;

    @Test
    void writeItemsToFile_1() throws IOException {
        File file = sharedTempDir.resolve("test1.txt").toFile();

        try (FileWriter fileWriter = new FileWriter(file.getAbsolutePath());
                PrintWriter printWriter = new PrintWriter(fileWriter)) {
            printWriter.print("Hello World");

        }

        assertEquals("Hello World", Files.readAllLines(file.toPath()).get(0));
    }

    @Test
    void writeItemsToFil_2() throws IOException {
        File file = sharedTempDir.resolve("test2.txt").toFile();

        try (FileWriter fileWriter = new FileWriter(file.getAbsolutePath());
                PrintWriter printWriter = new PrintWriter(fileWriter)) {
            printWriter.print("Hello World");

        }

        assertEquals("Hello World", Files.readAllLines(file.toPath()).get(0));
    }

}

Run above test class, you will observe two test methods get executed successfully.

 

 

 

 

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