What's the equivalent of org.junit.runner.JUni

问题:

The following code started in JUnit4 and has been mostly translated into JUnit5 except for main(). The reason I'm writing it this way is that I'm demonstrating TDD and I have multiple versions of the StringInverter implementation, each of which implements more features and passes more tests. Here is the StringInverter interface:

interface StringInverter {
  public String invert(String str);
}

And here's the almost-compiling-with-JUnit5 class:

import java.util.*;
import org.junit.jupiter.api.*;
import static org.junit.jupiter.api.Assertions.*;
import org.junit.platform.runner.JUnitPlatform;

public class StringInverterTest {
  static StringInverter inverter;
  @Test
  public final void basicInversion_Succeed() {
    String in = "Exit, Pursued by a Bear.";
    String out = "eXIT, pURSUED BY A bEAR.";
    assertEquals(inverter.invert(in), out);
  }
  @Test
  public final void basicInversion_Fail() {
    expectThrows(RuntimeException.class, () -> {
      assertEquals(inverter.invert("X"), "X");
    });
  }
  @Test
  public final void allowedCharacters_Fail() {
    expectThrows(RuntimeException.class, () -> {
      inverter.invert(";-_()*&^%$#@!~`");
      inverter.invert("0123456789");
    });
  }
  @Test
  public final void allowedCharacters_Succeed() {
    inverter.invert("abcdefghijklmnopqrstuvwxyz ,.");
    inverter.invert("ABCDEFGHIJKLMNOPQRSTUVWXYZ ,.");
  }
  @Test
  public final void lengthLessThan26_Fail() {
    String str = "xxxxxxxxxxxxxxxxxxxxxxxxxx";
    assertTrue(str.length() > 25);
    expectThrows(RuntimeException.class, () -> {
      inverter.invert(str);
    });
  }
  @Test
  public final void lengthLessThan26_Succeed() {
    String str = "xxxxxxxxxxxxxxxxxxxxxxxxx";
    assertTrue(str.length() < 26);
    inverter.invert(str);
  }
  public static void main(String[] args) throws Exception{
    assertEquals(args.length, 1);
    inverter = (StringInverter)
      Class.forName(args[0]).newInstance();
    Result result = org.junit.runner.JUnitCore.runClasses(
      StringInverterTest.class);
    List<Failure> failures = result.getFailures();
    System.out.printf("%s has %d FAILURES:\n",
      args[0], failures.size());
    int count = 1;
    for(Failure f : failures) {
      System.out.printf("Failure %d:\n", count++);
      System.out.println(f.getDescription());
      System.out.println(f.getMessage());
    }
  }
}

main() worked with JUnit4, so my question is how to convert it to JUnit 5. Thanks!

回答1:

JUnit5 has launcher API in junit-platform-launcher module which is for programmatic test discovery and execution.

Detailed example is documented on their user guide chapter7.

回答2:

I found a solution how to start unit tests from main static method.

Dependencies:

org.junit.jupiter:junit-jupiter-api:5.2.0
org.junit.platform:junit-platform-launcher:1.2.0
org.junit.jupiter:junit-jupiter-engine:5.2.0

Code example:

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.function.Executable;

import org.junit.platform.launcher.core.LauncherDiscoveryRequestBuilder;
import org.junit.platform.launcher.Launcher;
import org.junit.platform.launcher.LauncherDiscoveryRequest;
import org.junit.platform.launcher.core.LauncherFactory;
import static org.junit.platform.engine.discovery.DiscoverySelectors.selectClass;
import org.junit.platform.launcher.listeners.SummaryGeneratingListener;
import org.junit.platform.launcher.listeners.TestExecutionSummary;
import org.junit.platform.launcher.listeners.TestExecutionSummary.Failure;
import java.util.List;

public class MyClass {
    public static void main(String args[]) {
    final LauncherDiscoveryRequest request = 
        LauncherDiscoveryRequestBuilder.request()
                                   .selectors(selectClass(MyClass.class))
                                   .build();

        final Launcher launcher = LauncherFactory.create();
        final SummaryGeneratingListener listener = new SummaryGeneratingListener();

        launcher.registerTestExecutionListeners(listener);
        launcher.execute(request);

        TestExecutionSummary summary = listener.getSummary();
        long testFoundCount = summary.getTestsFoundCount();
        List<Failure> failures = summary.getFailures();
        System.out.println("getTestsSucceededCount() - " + summary.getTestsSucceededCount());
        failures.forEach(failure -> System.out.println("failure - " + failure.getException()));
    }

    @Test
    void exceptionTesting() {
        Executable closureContainingCodeToTest = () -> {throw new IllegalArgumentException("a message");};
        Throwable throwable = assertThrows(IllegalArgumentException.class, closureContainingCodeToTest, "a message");
        assertEquals("a message", throwable.getMessage());
    }
}