EitherLeftProjectionTest.java

/*                        __    __  __  __    __  ___
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 *                         \____/__/  \__\____/__/.ɪᴏ
 * ᶜᵒᵖʸʳᶦᵍʰᵗ ᵇʸ ᵛᵃᵛʳ ⁻ ˡᶦᶜᵉⁿˢᵉᵈ ᵘⁿᵈᵉʳ ᵗʰᵉ ᵃᵖᵃᶜʰᵉ ˡᶦᶜᵉⁿˢᵉ ᵛᵉʳˢᶦᵒⁿ ᵗʷᵒ ᵈᵒᵗ ᶻᵉʳᵒ
 */
package io.vavr.control;

import io.vavr.API;
import io.vavr.AbstractValueTest;
import io.vavr.Tuple;
import io.vavr.Tuple2;
import org.junit.Test;

import java.util.*;

public class EitherLeftProjectionTest extends AbstractValueTest {

    // -- AbstractValueTest

    @Override
    protected <T> Either.LeftProjection<T, ?> empty() {
        return Either.<T, T> right(null).left();
    }

    @Override
    protected <T> Either.LeftProjection<T, ?> of(T element) {
        return Either.<T, T> left(element).left();
    }

    @SafeVarargs
    @Override
    protected final <T> Either.LeftProjection<T, ?> of(T... elements) {
        return of(elements[0]);
    }

    @Override
    protected boolean useIsEqualToInsteadOfIsSameAs() {
        return true;
    }

    @Override
    protected int getPeekNonNilPerformingAnAction() {
        return 1;
    }

    // -- LeftProjection

    // get

    @Test(expected = NoSuchElementException.class)
    public void shouldThrowOnGetOnLeftProjectionOfRight() {
        Either.right(1).left().get();
    }

    @Test
    public void shouldGetOnLeftProjectionOfLeft() {
        assertThat(Either.left(1).left().get()).isEqualTo(1);
    }

    // orElse

    @Test
    public void shouldLeftProjectionOrElseLeftProjection() {
        final Either.LeftProjection<Integer, Integer> elseProjection = API.<Integer, Integer>Left(2).left();
        assertThat(API.Left(1).left().orElse(elseProjection).get()).isEqualTo(1);
        assertThat(API.Right(1).left().orElse(elseProjection).get()).isEqualTo(2);
    }

    @Test
    public void shouldLeftProjectionOrElseLeftProjectionFromSupplier() {
        final Either.LeftProjection<Integer, Integer> elseProjection = API.<Integer, Integer>Left(2).left();
        assertThat(API.Left(1).left().orElse(() -> elseProjection).get()).isEqualTo(1);
        assertThat(API.Right(1).left().orElse(() -> elseProjection).get()).isEqualTo(2);
    }

    // getOrElse

    @Test
    public void shouldReturnLeftWhenOrElseOnLeftProjectionOfLeft() {
        final Integer actual = Either.left(1).left().getOrElse(2);
        assertThat(actual).isEqualTo(1);
    }

    @Test
    public void shouldReturnOtherWhenOrElseOnLeftProjectionOfRight() {
        final Integer actual = Either.<Integer, String> right("1").left().getOrElse(2);
        assertThat(actual).isEqualTo(2);
    }

    // getOrElse(Function)

    @Test
    public void shouldReturnLeftWhenOrElseGetGivenFunctionOnLeftProjectionOfLeft() {
        final Integer actual = Either.left(1).left().getOrElseGet(r -> 2);
        assertThat(actual).isEqualTo(1);
    }

    @Test
    public void shouldReturnOtherWhenOrElseGetGivenFunctionOnLeftProjectionOfRight() {
        final Integer actual = Either.<Integer, String> right("1").left().getOrElseGet(r -> 2);
        assertThat(actual).isEqualTo(2);
    }

    // orElseRun

    @Test
    public void shouldReturnLeftWhenOrElseRunOnLeftProjectionOfLeft() {
        final boolean[] actual = new boolean[] { true };
        Either.left(1).left().orElseRun(s -> actual[0] = false);
        assertThat(actual[0]).isTrue();
    }

    @Test
    public void shouldReturnOtherWhenOrElseRunOnLeftProjectionOfRight() {
        final boolean[] actual = new boolean[] { false };
        Either.right("1").left().orElseRun(s -> {
            actual[0] = true;
        });
        assertThat(actual[0]).isTrue();
    }

    // getOrElseThrow(Function)

    @Test
    public void shouldReturnLeftWhenOrElseThrowWithFunctionOnLeftProjectionOfLeft() {
        final Integer actual = Either.<Integer, String> left(1).left().getOrElseThrow(s -> new RuntimeException(s));
        assertThat(actual).isEqualTo(1);
    }

    @Test(expected = RuntimeException.class)
    public void shouldThrowWhenOrElseThrowWithFunctionOnLeftProjectionOfRight() {
        Either.right("1").left().getOrElseThrow(s -> new RuntimeException(s));
    }

    // toOption

    @Test
    public void shouldConvertLeftProjectionOfLeftToSome() {
        assertThat(Either.left(1).left().toOption()).isEqualTo(Option.of(1));
    }

    @Test
    public void shouldConvertLeftProjectionOfRightToNone() {
        assertThat(Either.right("x").left().toOption()).isEqualTo(Option.none());
    }

    // toEither

    @Test
    public void shouldConvertLeftProjectionOfLeftToEither() {
        final Either<Integer, String> self = Either.left(1);
        assertThat(self.left().toEither()).isEqualTo(self);
    }

    @Test
    public void shouldConvertLeftProjectionOfRightToEither() {
        final Either<Integer, String> self = Either.right("1");
        assertThat(self.left().toEither()).isEqualTo(self);
    }

    // toJavaOptional

    @Test
    public void shouldConvertLeftProjectionOfLeftToJavaOptional() {
        assertThat(Either.left(1).left().toJavaOptional()).isEqualTo(Optional.of(1));
    }

    @Test
    public void shouldConvertLeftProjectionOfRightToJavaOptional() {
        assertThat(Either.<Integer, String> right("x").left().toJavaOptional()).isEqualTo(Optional.empty());
    }

    // filter

    @Test
    public void shouldFilterSomeOnLeftProjectionOfLeftIfPredicateMatches() {
        final boolean actual = Either.left(1).left().filter(i -> true).toOption().isDefined();
        assertThat(actual).isTrue();
    }

    @Test
    public void shouldFilterNoneOnLeftProjectionOfLeftIfPredicateNotMatches() {
        assertThat(Either.left(1).left().filter(i -> false)).isEqualTo(Option.none());
    }

    @Test
    public void shouldFilterSomeOnLeftProjectionOfRightIfPredicateMatches() {
        final boolean actual = Either.right("1").left().filter(i -> true).isDefined();
        assertThat(actual).isTrue();
    }

    @Test
    public void shouldFilterNoneOnLeftProjectionOfRightIfPredicateNotMatches() {
        final boolean actual = Either.right("1").left().filter(i -> false).isDefined();
        assertThat(actual).isTrue();
    }

    // flatMap

    @Test
    public void shouldFlatMapOnLeftProjectionOfLeft() {
        final Either<Integer, String> actual = Either.<Integer, String> left(1).left().flatMap(i -> Either.<Integer, String> left(i + 1).left()).toEither();
        assertThat(actual).isEqualTo(Either.left(2));
    }

    @Test
    public void shouldFlatMapOnLeftProjectionOfRight() {
        final Either<Integer, String> actual = Either.<Integer, String> right("1").left().flatMap(i -> Either.<Integer, String> left(i + 1).left()).toEither();
        assertThat(actual).isEqualTo(Either.right("1"));
    }

    @Test
    public void shouldFlatMapLeftProjectionOfRightOnLeftProjectionOfLeft() {
        final Either<String, String> good = Either.left("good");
        final Either<String, String> bad = Either.right("bad");
        final Either.LeftProjection<Tuple2<String, String>, String> actual = good.left().flatMap(g -> bad.left().map(b -> Tuple.of(g, b)));
        assertThat(actual.toEither()).isEqualTo(Either.right("bad"));

    }

    // -- exists

    @Test
    public void shouldBeAwareOfPropertyThatHoldsExistsOfLeftProjectionOfLeft() {
        assertThat(Either.left(1).left().exists(i -> i == 1)).isTrue();
    }

    @Test
    public void shouldBeAwareOfPropertyThatNotHoldsExistsOfLeftProjectionOfLeft() {
        assertThat(Either.left(1).left().exists(i -> i == 2)).isFalse();
    }

    @Test
    public void shouldNotHoldPropertyExistsOfLeftProjectionOfRight() {
        assertThat(Either.left(1).right().exists(e -> true)).isFalse();
    }

    // -- forall

    @Test
    public void shouldBeAwareOfPropertyThatHoldsForAllOfLeftProjectionOfLeft() {
        assertThat(Either.left(1).left().forAll(i -> i == 1)).isTrue();
    }

    @Test
    public void shouldBeAwareOfPropertyThatNotHoldsForAllOfLeftProjectionOfLeft() {
        assertThat(Either.left(1).left().forAll(i -> i == 2)).isFalse();
    }

    @Test// a property holds for all elements of no elements
    public void shouldNotHoldPropertyForAllOfLeftProjectionOfRight() {
        assertThat(Either.left(1).right().forAll(e -> true)).isTrue();
    }

    // forEach

    @Test
    public void shouldForEachOnLeftProjectionOfLeft() {
        final List<Integer> actual = new ArrayList<>();
        Either.left(1).left().forEach(actual::add);
        assertThat(actual).isEqualTo(Collections.singletonList(1));
    }

    @Test
    public void shouldForEachOnLeftProjectionOfRight() {
        final List<Integer> actual = new ArrayList<>();
        Either.<Integer, String> right("1").left().forEach(actual::add);
        assertThat(actual.isEmpty()).isTrue();
    }

    // peek

    @Test
    public void shouldPeekOnLeftProjectionOfLeft() {
        final List<Integer> actual = new ArrayList<>();
        final Either<Integer, String> testee = Either.<Integer, String> left(1).left().peek(actual::add).toEither();
        assertThat(actual).isEqualTo(Collections.singletonList(1));
        assertThat(testee).isEqualTo(Either.left(1));
    }

    @Test
    public void shouldPeekOnLeftProjectionOfRight() {
        final List<Integer> actual = new ArrayList<>();
        final Either<Integer, String> testee = Either.<Integer, String> right("1").left().peek(actual::add).toEither();
        assertThat(actual.isEmpty()).isTrue();
        assertThat(testee).isEqualTo(Either.right("1"));
    }

    // map

    @Test
    public void shouldMapOnLeftProjectionOfLeft() {
        final Either<Integer, String> actual = Either.<Integer, String> left(1).left().map(i -> i + 1).toEither();
        assertThat(actual).isEqualTo(Either.left(2));
    }

    @Test
    public void shouldMapOnLeftProjectionOfRight() {
        final Either<Integer, String> actual = Either.<Integer, String> right("1").left().map(i -> i + 1).toEither();
        assertThat(actual).isEqualTo(Either.right("1"));
    }

    // iterator

    @Test
    public void shouldReturnIteratorOfLeftOfLeftProjection() {
        assertThat((Iterator<Integer>) Either.left(1).left().iterator()).isNotNull();
    }

    @Test
    public void shouldReturnIteratorOfRightOfLeftProjection() {
        assertThat((Iterator<Object>) Either.right(1).left().iterator()).isNotNull();
    }

    // equals

    @Test
    public void shouldEqualLeftProjectionOfLeftIfObjectIsSame() {
        final Either.LeftProjection<?, ?> l = Either.left(1).left();
        assertThat(l.equals(l)).isTrue();
    }

    @Test
    public void shouldEqualLeftProjectionOfRightIfObjectIsSame() {
        final Either.LeftProjection<?, ?> l = Either.right(1).left();
        assertThat(l.equals(l)).isTrue();
    }

    @Test
    public void shouldNotEqualLeftProjectionOfLeftIfObjectIsNull() {
        assertThat(Either.left(1).left().equals(null)).isFalse();
    }

    @Test
    public void shouldNotEqualLeftProjectionOfRightIfObjectIsNull() {
        assertThat(Either.right(1).left().equals(null)).isFalse();
    }

    @Test
    public void shouldNotEqualLeftProjectionOfLeftIfObjectIsOfDifferentType() {
        assertThat(Either.left(1).left().equals(new Object())).isFalse();
    }

    @Test
    public void shouldNotEqualLeftProjectionOfRightIfObjectIsOfDifferentType() {
        assertThat(Either.right(1).left().equals(new Object())).isFalse();
    }

    @Test
    public void shouldEqualLeftProjectionOfLeft() {
        assertThat(Either.left(1).left()).isEqualTo(Either.left(1).left());
    }

    @Test
    public void shouldEqualLeftProjectionOfRight() {
        assertThat(Either.right(1).left()).isEqualTo(Either.right(1).left());
    }

    // hashCode

    @Test
    public void shouldHashLeftProjectionOfLeft() {
        assertThat(Either.left(1).left().hashCode()).isEqualTo(Objects.hashCode(Either.right(1)));
    }

    @Test
    public void shouldHashLeftProjectionOfRight() {
        assertThat(Either.right(1).left().hashCode()).isEqualTo(Objects.hashCode(Either.left(1)));
    }

    // toString

    @Test
    public void shouldConvertLeftProjectionOfLeftToString() {
        assertThat(Either.left(1).left().toString()).isEqualTo("LeftProjection(Left(1))");
    }

    @Test
    public void shouldConvertLeftProjectionOfRightToString() {
        assertThat(Either.right(1).left().toString()).isEqualTo("LeftProjection(Right(1))");
    }

    // -- transform()

    @Test
    public void shouldTransform() {
        final String transformed = of(1).transform(v -> String.valueOf(v.get()));
        assertThat(transformed).isEqualTo("1");
    }

    // -- spliterator

    @Test
    public void shouldHaveSizedSpliterator() {
        assertThat(of(1).spliterator().hasCharacteristics(Spliterator.SIZED | Spliterator.SUBSIZED)).isTrue();
    }

    @Test
    public void shouldHaveOrderedSpliterator() {
        assertThat(of(1).spliterator().hasCharacteristics(Spliterator.ORDERED)).isTrue();
    }

    @Test
    public void shouldReturnSizeWhenSpliterator() {
        assertThat(of(1).spliterator().getExactSizeIfKnown()).isEqualTo(1);
    }
}