Package org.junit.rules

Class ExternalResource

  • All Implemented Interfaces:
    TestRule
    Direct Known Subclasses:
    TemporaryFolder
    public abstract class ExternalResource
extends Object
implements TestRule
    A base class for Rules (like TemporaryFolder) that set up an external resource before a test (a file, socket, server, database connection, etc.), and guarantee to tear it down afterward: 
     public static class UsesExternalResource {
  Server myServer= new Server();

  @Rule
  public ExternalResource resource= new ExternalResource() {
      @Override
      protected void before() throws Throwable {
          myServer.connect();
         };

      @Override
      protected void after() {
          myServer.disconnect();
         };
     };

  @Test
  public void testFoo() {
      new Client().run(myServer);
     }
 }
    Since:
    4.7

    • Method Detail

      • apply

        public Statement apply​(Statement base,
                       Description description)
        Description copied from interface: TestRule
        Modifies the method-running Statement to implement this test-running rule.
        Specified by:
        apply in interface TestRule
        Parameters:
        base - The Statement to be modified
        description - A Description of the test implemented in base
        Returns:
        a new statement, which may be the same as base, a wrapper around base, or a completely new Statement.

      • before

        protected void before()
               throws Throwable
        Override to set up your specific external resource.
        Throws:
        Throwable - if setup fails (which will disable after

      • after

        protected void after()
        Override to tear down your specific external resource.