BookResourceTest.java

package nl.first8.generativetesting.rest;

import org.hamcrest.beans.SamePropertyValuesAs;
import org.junit.runner.RunWith;

import com.pholser.junit.quickcheck.From;
import com.pholser.junit.quickcheck.Property;
import com.pholser.junit.quickcheck.generator.Ctor;

import com.pholser.junit.quickcheck.generator.GenerationStatus;
import com.pholser.junit.quickcheck.generator.Generator;
import com.pholser.junit.quickcheck.generator.java.lang.StringGenerator;
import com.pholser.junit.quickcheck.generator.java.time.LocalDateGenerator;
import com.pholser.junit.quickcheck.random.SourceOfRandomness;
import com.pholser.junit.quickcheck.runner.JUnitQuickcheck;

import nl.first8.generativetesting.Author;
import nl.first8.generativetesting.Book;
import nl.first8.generativetesting.Publisher;
import nl.first8.generativetesting.rest.BookResource;

import static org.junit.Assert.assertThat;

import java.time.LocalDate;

@RunWith(JUnitQuickcheck.class)
public final class BookResourceTest {

    /**
     * Example using build types, which junit-quickcheck can generate.
     * 
     * @param title generated by junit-quickcheck
     * @param author generated by junit-quickcheck
     * @param publisher generated by junit-quickcheck
     * @param publishedOn generated by junit-quickcheck
     */
    @Property
    public void testConversions(//
            final String title, //
            final String author, //
            final String publisher, //
            final LocalDate publishedOn) {

        // Given a book
        final Book book = new Book(title, new Author(author),
                new Publisher(publisher), publishedOn);

        // When we create a resource based on that book
        final BookResource resource = BookResource.fromBook(book);
        // And convert the resource back to a book
        final Book converted = resource.toBook();

        // Then we expected the result to have the same property values as the
        // original book
        assertThat(converted, SamePropertyValuesAs.samePropertyValuesAs(book));
    }

    /**
     * Example using a user defined type, of which all constructor parameters are
     * build-in types.
     * 
     * @param resource generated by junit-quickcheck
     */
    @Property
    public void testConversions(// Given a resource
            final @From(Ctor.class) BookResource resource) {

        // When we convert the resource into a book
        final Book book = resource.toBook();
        // And we convert the book back to a resource
        final BookResource converted = BookResource.fromBook(book);

        // Then we expect the result to have the same property values as
        // the original resource
        assertThat(converted,
                SamePropertyValuesAs.samePropertyValuesAs(resource));
    }

    /**
     * Because book has a constructor with user defined data types (Author and
     * Publisher), the Ctor.class generator will not work.
     * 
     * Therefore, we need to create a generator, to generate a book.
     */
    public static final class BookGenerator extends Generator<Book> {
        /**
         * Generator to generate strings for title, author name and publisher
         * name.
         */
        private final StringGenerator stringGenerator = new StringGenerator();
        /**
         * Generator to generate dates.
         */
        private final LocalDateGenerator localDateGenerator =
                new LocalDateGenerator();

        public BookGenerator() {
            super(Book.class);
        }

        @Override
        public Book generate(final SourceOfRandomness random,
                final GenerationStatus status) {
            final String title = stringGenerator.generate(random, status);
            final String author = stringGenerator.generate(random, status);
            final String publisher = stringGenerator.generate(random, status);
            final LocalDate publishedOn =
                    localDateGenerator.generate(random, status);
            final Book book = new Book(title, new Author(author),
                    new Publisher(publisher), publishedOn);
            return book;
        }
    }

    /**
     * Example using the BookGenerator defined above, to generate books
     * 
     * @param book generated by junit-quickcheck
     */
    @Property
    public void testConversions(// Given a book
            final @From(BookGenerator.class) Book book) {

        // When we convert the book to a resource
        final BookResource resource = BookResource.fromBook(book);
        // and we convert the resource back to a book
        final Book converted = resource.toBook();

        // Then we expect the result to have the same property values as the
        // original book
        assertThat(converted, SamePropertyValuesAs.samePropertyValuesAs(book));
    }
}