JUnit 5 – @TempDir Example
Example1: A simple example to understand how to use @TempDir in JUnit 5 test class.
Java
import org.junit.jupiter.api.Test; import org.junit.jupiter.api.io.TempDir; import java.io.File; import java.io.IOException; import java.nio.file.Path; import static org.junit.jupiter.api.Assertions.assertTrue; public class Example1 { @Test void testUsingTempDir(@TempDir Path tempDir) throws IOException { // Using the temporary direcotry in out test File tempFile = new File(tempDir.toFile(), "example1.txt"); assertTrue(tempFile.createNewFile()); } } |
Explanation of above program:
In the above example program the @TempDir annotation is used to inject a temporary directory (Path tempDir) to the test method. the test creates a file within the temporary directory, and the assertTrue() statement checks whether the file was successfully created or not.
Example2: Program to demonstrate the use of @TempDir with multiple parameters in a JUnit 5 test class.
Java
import org.junit.jupiter.api.Test; import org.junit.jupiter.api.io.TempDir; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import static org.junit.jupiter.api.Assertions.assertTrue; public class Example2 { @Test void testWithMultipleTempDirs(@TempDir Path tempDir1, @TempDir Path tempDir2) throws IOException { // Test logic using tempDir1 Path file1 = tempDir1.resolve("file1.txt"); Files.createFile(file1); assertTrue(Files.exists(file1)); // Test logic using tempDir2 Path file2 = tempDir2.resolve("file2.txt"); Files.createFile(file2); assertTrue(Files.exists(file2)); } } |
Explanation of above program:
In the above example we have declared two parameters, tempDir1, tempDir2 of type path, Now JUnit 5 automatically creates the temporary directories for tempDir1 and tempDir2 before testWithMultipleTempDirs method executed.
Each temporary directory tempDir1 and tempDir2 creates the files file1.txt and file2.txt. After the completion of JUnit 5 test method the temporary directories will clean up automatically.
Note: The parameters for @TempDir should be a type of “java.nio.file.Path ” or “java.io.File”.
Advantages of JUnit 5 – @TempDir
- The major advantages of the @TempDir annotation is its automatic cleanup mechanism, flexibility, readability and also the efficiency.
- Integration with the external libraries which requires the temporary directories during the testing of our test methods.
- With the usage of automatic cleanup mechanism, there is no need for explicit cleanup code at the end of the test methods.
Features of @TempDir
- @TempDir will automatically create the temporary directory before the test method runs.
- JUnit 5 will automatically clean the temporary directory after the test method completes irrespective of the output.
- we can create the single method with multiple temporary directories based on the requirements.
- It eliminates the need of manual setup and removing of the temporary directories.
JUnit 5 – @TempDir
Junit 5 is a Unit testing framework for the Java programming language. It is a simple framework for writing tests for Java codes using Java. Whenever we write code, we have to test it. Junit is the primary source for writing the test cases. the latest version of Junit is Junit 5 Jupiter.