### Question:
RetryPolicies { public static RetryPolicy justCall() { return JustCallRetryPolicyHolder.JUST_CALL; } private  RetryPolicies(); static SimpleRetryPolicy.Builder repeat(int retries); static RetryPolicy justCall();  }### Answer:
@Test public void testJustCallRetryPolicy() throws Exception { CountDownLatch loadLatch = new CountDownLatch(1); NodeConfigSource source = TestingSource.builder() .retryPolicy(RetryPolicies.justCall()) .loadLatch(loadLatch) .build(); BuilderImpl.ConfigContextImpl context = Mockito.mock(BuilderImpl.ConfigContextImpl.class); ConfigSourceRuntimeImpl csr = new ConfigSourceRuntimeImpl(context, source); Optional<ObjectNode> load = csr.load(); assertThat(load, not(Optional.empty())); assertThat(loadLatch.await(50, TimeUnit.MILLISECONDS), is(true)); }