content: package io.activej.datastream.processor.transformer.impl;
  
  import io.activej.datastream.consumer.StreamConsumer;
  import io.activej.datastream.consumer.ToListStreamConsumer;
  import io.activej.datastream.processor.transformer.StreamTransformer;
  import io.activej.datastream.supplier.StreamSupplier;
  import io.activej.datastream.supplier.StreamSuppliers;
  import io.activej.promise.Promise;
  import io.activej.test.ExpectedException;
  import io.activej.test.rules.EventloopRule;
  import org.junit.ClassRule;
  import org.junit.Test;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import static io.activej.datastream.TestStreamTransformers.*;
  import static io.activej.datastream.TestUtils.assertClosedWithError;
  import static io.activej.datastream.TestUtils.assertEndOfStream;
  import static io.activej.datastream.supplier.StreamSuppliers.concat;
  import static io.activej.promise.TestUtils.await;
  import static io.activej.promise.TestUtils.awaitException;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertSame;
  
  public class MapperTest {
  	@ClassRule
  	public static final EventloopRule eventloopRule = new EventloopRule();
  
  	@Test
  	public void testFunction() {
  		StreamSupplier<Integer> supplier = StreamSuppliers.ofValues(1, 2, 3);
  		ToListStreamConsumer<Integer> consumer = ToListStreamConsumer.create();
  		StreamTransformer<Integer, Integer> mapper = new Mapper<>(input -> input * input);
  
  		await(supplier.transformWith(mapper)
  			.streamTo(consumer.transformWith(oneByOne())));
  
  		assertEquals(List.of(1, 4, 9), consumer.getList());
  
  		assertEndOfStream(supplier);
  		assertEndOfStream(mapper);
  		assertEndOfStream(consumer);
  	}
  
  	@Test
  	public void testFunctionConsumerError() {
  		StreamTransformer<Integer, Integer> mapper = new Mapper<>(input -> input * input);
  
  		List<Integer> list = new ArrayList<>();
  		StreamSupplier<Integer> source1 = StreamSuppliers.ofValues(1, 2, 3);
  		StreamConsumer<Integer> consumer = ToListStreamConsumer.create(list);
  		ExpectedException exception = new ExpectedException("Test Exception");
  
  		Exception e = awaitException(source1.transformWith(mapper)
  			.streamTo(consumer
  				.transformWith(decorate(promise -> promise.then(
  					item -> item == 2 * 2 ? Promise.ofException(exception) : Promise.of(item))))));
  
  		assertSame(exception, e);
  		assertEquals(List.of(1, 4), list);
  
  		assertClosedWithError(source1);
  		assertClosedWithError(consumer);
  		assertClosedWithError(mapper);
  	}
  
  	@Test
  	public void testFunctionSupplierError() {
  		StreamTransformer<Integer, Integer> mapper = new Mapper<>(input -> input * input);
  
  		ExpectedException exception = new ExpectedException("Test Exception");
  		StreamSupplier<Integer> supplier = concat(
  			StreamSuppliers.ofValues(1, 2, 3),
  			StreamSuppliers.ofValues(4, 5, 6),
  			StreamSuppliers.closingWithError(exception)
  		);
  
  		ToListStreamConsumer<Integer> consumer = ToListStreamConsumer.create();
  
  		Exception e = awaitException(supplier.transformWith(mapper)
  			.streamTo(consumer));
  
  		assertSame(exception, e);
  		assertEquals(List.of(1, 4, 9, 16, 25, 36), consumer.getList());
  
  		assertClosedWithError(consumer);
  		assertClosedWithError(mapper);
  	}
  
  	@Test
  	public void testMappedConsumer() {
  		StreamSupplier<Integer> supplier = StreamSuppliers.ofValues(1, 2, 3);
  		ToListStreamConsumer<Integer> consumer = ToListStreamConsumer.create();
  		StreamTransformer<Integer, Integer> mapper = new Mapper<>(input -> input * input);
  
  		StreamConsumer<Integer> mappedConsumer = consumer
  			.transformWith(mapper)
  			.transformWith(oneByOne());
  
  		await(supplier.streamTo(mappedConsumer));
  
  		assertEquals(List.of(1, 4, 9), consumer.getList());
  
  		assertEndOfStream(supplier);
  		assertEndOfStream(mapper);
  		assertEndOfStream(consumer);
  	}
  
  	@Test
  	public void testConsecutiveMappers() {
  		StreamSupplier<Integer> supplier = StreamSuppliers.ofValues(1, 2, 3, 4, 5, 6);
  		ToListStreamConsumer<Integer> consumer = ToListStreamConsumer.create();
  		StreamTransformer<Integer, Integer> squareMapper = new Mapper<>(input -> input * input);
  		StreamTransformer<Integer, Integer> doubleMapper = new Mapper<>(input -> input * 2);
  		StreamTransformer<Integer, Integer> mul10Mapper = new Mapper<>(input -> input * 10);
  
  		await(supplier.transformWith(squareMapper).transformWith(doubleMapper)
  			.streamTo(consumer.transformWith(mul10Mapper).transformWith(randomlySuspending())));
  
  		assertEquals(List.of(20, 80, 180, 320, 500, 720), consumer.getList());
  
  		assertEndOfStream(supplier);
  		assertEndOfStream(squareMapper);
  		assertEndOfStream(doubleMapper);
  		assertEndOfStream(mul10Mapper);
  		assertEndOfStream(consumer);
  	}
  }
  