https://twitter.com/jessewilson/status/1123055645824028672 in Java

AssertFailsWith.java

public class AssertFailsWith {
  public interface RunnableThatThrows {
    void run() throws Throwable;
  }
  public static <T extends Throwable> void assertFailsWith(Class<T> throwableClass, RunnableThatThrows runnable) {
    try {
      runnable.run();
      fail();
    } catch (Throwable throwable) {
      assertTrue(throwableClass.isInstance(throwable));
    }
  }
  
  public static void main(String[] args) {
    // succeeds
    assertFailsWith(IOException.class, () -> {
      throw new IOException();
    );
    
    //fails
    assertFailsWith(IOException.class, () -> {
      throw new RuntimeException();
    );
  }
}