package io.atlassian.fugue;
   
   import org.junit.Test;
   
   import java.util.Iterator;
   import java.util.function.Supplier;
   
   import static org.hamcrest.Matchers.is;
   import static org.junit.Assert.assertThat;
  
  public class IteratorAbstractTest {
  
    public <A> Iterator<A> newIterator(final Supplier<A> s) {
      return new Iterators.Abstract<A>() {
        @Override protected A computeNext() {
          return s.get();
        }
      };
    }
  
    @Test(expected = IllegalStateException.class) public void testComputeNextThrows() {
      final Iterator<Object> objectIterator = newIterator(() -> {
        throw new RuntimeException();
      });
      try {
        objectIterator.next();
      } catch (final RuntimeException ignored) {}
      objectIterator.next();
    }
  
    @Test public void testEndOfData() {
      final Iterator<String> stopingIterator = new Iterators.Abstract<String>() {
        boolean secondTime = false;
  
        @Override protected String computeNext() {
          if (!secondTime) {
            secondTime = true;
            return "first";
          }
          return endOfData();
        }
      };
      assertThat(stopingIterator.hasNext(), is(true));
      assertThat(stopingIterator.next(), is("first"));
      assertThat(stopingIterator.hasNext(), is(false));
    }
  
    @Test public void testHasNext() {
      final Iterator<Integer> integerIterator = newIterator(() -> 1);
      assertThat(integerIterator.hasNext(), is(true));
    }
  
    @Test public void testNext() {
      final Iterator<Integer> integerIterator = newIterator(() -> 1);
      assertThat(integerIterator.next(), is(1));
    }
  }