com.github.lpandzic.junit.bdd.Then Maven / Gradle / Ivy

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package com.github.lpandzic.junit.bdd;

import java.util.Optional;
import java.util.function.Consumer;

/**
 * Defines expected outcomes produced by {@link When}.
 *
 * @author Lovro Pandzic
 */
public final class Then {

    /**
     * Used to describe expected thrown exception.
     *
     * @param  type of expected {@link Throwable}
     */
    public static final class Throws {

        private final Bdd bdd;

        public Throws(Bdd bdd) {

            this.bdd = bdd;
        }

        public void then(Consumer consumer) {

            Optional throwable = bdd.takeThrownException();
            consumer.accept(throwable.orElse(null));
        }

        @SuppressWarnings("unchecked")
        public  void thenChecked(Consumer consumer) {

            Optional throwable = bdd.takeThrownException();

            try {
                consumer.accept((E) throwable.orElse(null));
            }  catch (ClassCastException e) {
                bdd.throwUnexpectedException(throwable.get());
            }
        }
    }

    /**
     * Used to describe expected returned value.
     *
     * @param  type of returned value
     */
    public static final class Returns {

        private final Optional value;

        public Returns(Optional value) {

            this.value = value;
        }

        public void then(Consumer consumer) {

            consumer.accept(value.orElse(null));
        }
    }
}