code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.rxjava3.internal.operators.single;
  
  import static org.junit.Assert.*;
  
  import java.util.*;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class SingleInternalHelperTest extends RxJavaTest {
  
      @Test
      public void utilityClass() {
          TestHelper.checkUtilityClass(SingleInternalHelper.class);
      }
  
      @Test
      public void noSuchElementCallableEnum() {
          assertEquals(1, SingleInternalHelper.NoSuchElementSupplier.values().length);
          assertNotNull(SingleInternalHelper.NoSuchElementSupplier.valueOf("INSTANCE"));
      }
  
      @Test
      public void toFlowableEnum() {
          assertEquals(1, SingleInternalHelper.ToFlowable.values().length);
          assertNotNull(SingleInternalHelper.ToFlowable.valueOf("INSTANCE"));
      }
  
      @Test
      public void singleIterableToFlowableIterable() {
          Iterable<? extends Flowable<Integer>> it = SingleInternalHelper.iterableToFlowable(
                  Collections.singletonList(Single.just(1)));
  
          Iterator<? extends Flowable<Integer>> iter = it.iterator();
  
          if (iter.hasNext()) {
              iter.next().test().assertResult(1);
              if (iter.hasNext()) {
                  fail("Iterator reports an additional element");
              }
          } else {
              fail("Iterator was empty");
          }
      }
  }
  