diff --git a/bookstore/src/test/java/com/fjordtek/bookstore/model/auth/AuthRepositoriesTest.java b/bookstore/src/test/java/com/fjordtek/bookstore/model/auth/AuthRepositoriesTest.java
new file mode 100644
index 0000000..dacbafb
--- /dev/null
+++ b/bookstore/src/test/java/com/fjordtek/bookstore/model/auth/AuthRepositoriesTest.java
@@ -0,0 +1,344 @@
+// Pekka Helenius <fincer89@hotmail.com>, Fjordtek 2020
+
+package com.fjordtek.bookstore.model.auth;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.security.SecureRandom;
+
+import javax.validation.ConstraintViolationException;
+
+import org.junit.Test;
+import org.junit.jupiter.api.MethodOrderer.Alphanumeric;
+import org.junit.jupiter.api.TestMethodOrder;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.dao.DataIntegrityViolationException;
+import org.springframework.orm.jpa.JpaSystemException;
+import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.test.context.junit4.SpringRunner;
+
+/**
+ *
+ * TODO: N/A
+ *
+ * @author Pekka Helenius
+ */
+
+@RunWith(SpringRunner.class)
+@DataJpaTest
+@TestMethodOrder(Alphanumeric.class)
+public class AuthRepositoriesTest {
+
+	@Autowired
+	private RoleRepository     roleRepository;
+
+	@Autowired
+	private UserRepository     userRepository;
+
+	@Autowired
+	private UserRoleRepository userRoleRepository;
+
+	private PasswordEncoder    passwordEncoder = new BCryptPasswordEncoder(14, new SecureRandom());
+
+	//////////////////////////////
+
+	@Test
+	public void testA_CreateRole() {
+		Role roleA = roleRepository.save(new Role("TEST"));
+		assertThat(roleA).isNotNull();
+	}
+
+	@Test
+	public void testB_CreateRoleWithoutNameShouldFail() {
+		assertThrows(
+				ConstraintViolationException.class, () -> {
+					roleRepository.save(new Role());
+					roleRepository.findAll().forEach(System.out::print);
+				}
+				);
+	}
+
+	@Test
+	public void testC_CreateRoleDuplicateNameShouldFail() {
+
+		assertThrows(
+				DataIntegrityViolationException.class, () -> {
+
+					roleRepository.save(new Role("FOO"));
+					roleRepository.save(new Role("FOO"));
+
+					roleRepository.findAll().forEach(System.out::print);
+				});
+	}
+
+	@Test
+	public void testD_DeleteUnusedRole() {
+
+		Role roleA = roleRepository.save(new Role("FOO"));
+		Long id = roleA.getId();
+		roleRepository.delete(roleA);
+
+		assertThat(roleRepository.findById(id)).isEmpty();
+
+	}
+
+	@Test
+	public void testE_ChangeRoleName() {
+
+		String nameA = "FOO";
+		String nameB = "BAR";
+
+		Role roleA = roleRepository.save(new Role(nameA));
+		roleA.setName(nameB);
+		roleRepository.save(roleA);
+
+		assertThat(roleA.getName().equals(nameA)).isEqualTo(false);
+
+		//System.out.println(roleRepository.findById(roleA.getId()).get().getName());
+
+	}
+
+	//////////////////////////////
+
+	@Test
+	public void testF_CreateUser() {
+		User userA = userRepository.save(new User(
+				"foo",
+				passwordEncoder.encode("bar"),
+				"foo.bar@fjordtek.com"
+				)
+				);
+
+		assertThat(userA).isNotNull();
+	}
+
+	@Test
+	public void testG__CreateUserWithEmptyPasswordShouldFail() {
+
+		/*
+		 * NOTE: null password must be forced for empty/blank passwords
+		 * if sign up form is implemented.
+		 * BCryptPasswordEncoder encode method checks for null value only
+		 * and throws exception accordingly. It does not work on empty
+		 * ("") values.
+		 *
+		 */
+
+		assertThrows(
+				IllegalArgumentException.class, () -> {
+					userRepository.save(new User(
+							"bar",
+							passwordEncoder.encode(null),
+							"bar@fjordtek.com"
+							)
+							);
+				});
+
+	}
+
+	@Test
+	public void testH__CreateUserWithInvalidEmailShouldFail() {
+
+		assertThrows(
+				ConstraintViolationException.class, () -> {
+					userRepository.save(new User(
+							"foo",
+							passwordEncoder.encode("bar is foo"),
+							"bar//foobar.com"
+							)
+							);
+					userRepository.findAll().forEach(System.out::print);
+				});
+
+		assertThrows(
+				ConstraintViolationException.class, () -> {
+					userRepository.save(new User(
+							"foo",
+							passwordEncoder.encode("bar is foo"),
+							"bar||foobar.com"
+							)
+							);
+					userRepository.findAll().forEach(System.out::print);
+				});
+	}
+
+	@Test
+	public void testI_CreateUserWithEmptyUsernameShouldFail() {
+
+		assertThrows(
+				ConstraintViolationException.class, () -> {
+					userRepository.save(new User(
+							"",
+							passwordEncoder.encode("bar is foo"),
+							"bar@foobar.com"
+							)
+							);
+					userRepository.findAll().forEach(System.out::print);
+				});
+
+	}
+
+	@Test
+	public void testJ_CreateUserDuplicateUsernamesShouldFail() {
+
+		assertThrows(
+				DataIntegrityViolationException.class, () -> {
+
+					userRepository.save(new User(
+							"foo",
+							passwordEncoder.encode("foo"),
+							"foo@foo.com"
+							)
+							);
+
+					userRepository.save(new User(
+							"foo",
+							passwordEncoder.encode("bar"),
+							"bar@bar.com"
+							)
+							);
+
+					userRepository.findAll().forEach(System.out::print);
+				});
+
+	}
+
+	@Test
+	public void testK_DeleteExistingUser() {
+
+		User userA = userRepository.save(new User(
+				"foo",
+				passwordEncoder.encode("foo"),
+				"foo@foo.com"
+				)
+				);
+		Long id = userA.getId();
+		userRepository.delete(userA);
+
+		assertThat(userRepository.findById(id)).isEmpty();
+
+	}
+
+	@Test
+	public void testL_ChangeUserName() {
+
+		String nameA = "foo";
+		String nameB = "bar";
+
+		User userA = userRepository.save(new User(
+				nameA,
+				passwordEncoder.encode("foo"),
+				"foo@foo.com"
+				)
+				);
+		userA.setUsername(nameB);
+		userRepository.save(userA);
+
+		assertThat(userA.getUsername().equals(nameA)).isEqualTo(false);
+
+		//System.out.println(userRepository.findById(userA.getId()).get().getUsername());
+
+	}
+
+	//////////////////////////////
+
+	@Test
+	public void testK_JoinAddExistingRoleAndUser() {
+
+		User userA = userRepository.save(new User(
+				"foo",
+				passwordEncoder.encode("foo"),
+				"foo@foo.com"
+				)
+				);
+		Role roleA = new Role("FOO");
+
+		UserRole userRoleA = new UserRole(userA, roleA);
+		userRoleRepository.save(userRoleA);
+
+		assertThat(userRoleA).isNotNull();
+
+	}
+
+	@Test
+	public void testL_JoinSetRoleNullKeepUserShouldFail() {
+
+		assertThrows(
+				JpaSystemException.class, () -> {
+
+					User userA = userRepository.save(new User(
+							"foo",
+							passwordEncoder.encode("foo"),
+							"foo@foo.com"
+							)
+							);
+
+					userRepository.save(userA);
+					userRoleRepository.save(new UserRole(userA, null));
+				});
+
+	}
+
+	@Test
+	public void testM_JoinSetUserNullKeepRoleShouldFail() {
+
+		assertThrows(
+				JpaSystemException.class, () -> {
+					Role roleA = new Role("FOO");
+
+					roleRepository.save(roleA);
+					userRoleRepository.save(new UserRole(null, roleA));
+				});
+
+	}
+
+	@Test
+	public void testN_JoinAddDuplicatePrimaryKeyShouldFail() {
+
+		assertThrows(
+				DataIntegrityViolationException.class, () -> {
+
+					User userA = userRepository.save(new User(
+							"foo",
+							passwordEncoder.encode("foo"),
+							"foo@foo.com"
+							)
+							);
+					Role roleA = new Role("FOO");
+
+					userRepository.save(userA);
+					roleRepository.save(roleA);
+
+					userRoleRepository.save(new UserRole(userA, roleA));
+					userRoleRepository.save(new UserRole(userA, roleA));
+				});
+
+	}
+
+	@Test
+	public void testO_JoinDeleteExistingRoleAndUser() {
+
+		User userA = userRepository.save(new User(
+				"foo",
+				passwordEncoder.encode("foo"),
+				"foo@foo.com"
+				)
+				);
+		Role roleA = new Role("FOO");
+
+		userRepository.save(userA);
+		roleRepository.save(roleA);
+		UserRole userRoleA = new UserRole(userA, roleA);
+		userRoleRepository.save(userRoleA);
+
+		userRoleRepository.deleteByCompositeId(userA.getId(), roleA.getId());
+
+		assertThat(userRoleRepository.findByCompositeId(userA.getId(), roleA.getId())).isNull();
+
+	}
+
+}
diff --git a/bookstore/src/test/java/com/fjordtek/bookstore/model/book/BookRepositoriesTest.java b/bookstore/src/test/java/com/fjordtek/bookstore/model/book/BookRepositoriesTest.java
new file mode 100644
index 0000000..bf5f3d0
--- /dev/null
+++ b/bookstore/src/test/java/com/fjordtek/bookstore/model/book/BookRepositoriesTest.java
@@ -0,0 +1,351 @@
+// Pekka Helenius <fincer89@hotmail.com>, Fjordtek 2020
+
+package com.fjordtek.bookstore.model.book;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.math.BigDecimal;
+
+import javax.validation.ConstraintViolationException;
+
+import org.junit.Test;
+import org.junit.jupiter.api.MethodOrderer.Alphanumeric;
+import org.junit.jupiter.api.TestMethodOrder;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.dao.DataIntegrityViolationException;
+import org.springframework.orm.jpa.JpaSystemException;
+import org.springframework.test.context.junit4.SpringRunner;
+
+/**
+ *
+ * TODO: N/A
+ *
+ * @author Pekka Helenius
+ */
+
+@RunWith(SpringRunner.class)
+@DataJpaTest
+@TestMethodOrder(Alphanumeric.class)
+public class BookRepositoriesTest {
+
+	@Autowired
+	private BookRepository     bookRepository;
+
+	@Autowired
+	private BookHashRepository bookHashRepository;
+
+	@Autowired
+	private AuthorRepository   authorRepository;
+
+	@Autowired
+	private CategoryRepository categoryRepository;
+
+	//////////////////////////////
+
+	@Test
+	public void testA_CreateAuthor() {
+		Author authorA = authorRepository.save(new Author("Foo", "Bar"));
+		assertThat(authorA).isNotNull();
+	}
+
+	@Test
+	public void testB_CreateAuthorWithoutFirstName() {
+		Author authorA = authorRepository.save(new Author(null, "Bar"));
+		assertThat(authorA).isNotNull();
+	}
+
+	@Test
+	public void testC_CreateAuthorWithoutLastName() {
+		Author authorA = authorRepository.save(new Author("Foo", null));
+		assertThat(authorA).isNotNull();
+	}
+
+	@Test
+	public void testD_CreateAuthorDuplicateNameShouldPass() {
+		authorRepository.save(new Author("Foo", "Bar"));
+		authorRepository.save(new Author("Foo", "Bar"));
+
+		int savedAuthorsCount =
+				authorRepository
+				.findByFirstNameIgnoreCaseContainingAndLastNameIgnoreCaseContaining(
+						"Foo", "Bar"
+						).size();
+
+		assertThat(savedAuthorsCount).isEqualTo(2);
+	}
+
+	//////////////////////////////
+
+	@Test
+	public void testE_CreateCategory() {
+		Category categoryA = categoryRepository.save(new Category("FOO"));
+		assertThat(categoryA).isNotNull();
+	}
+
+	@Test
+	public void testF_CreateCategoryWithoutNameShouldFail() {
+
+		assertThrows(
+				ConstraintViolationException.class, () -> {
+					categoryRepository.save(new Category(null));
+					categoryRepository.findAll().forEach(System.out::print);
+				});
+
+	}
+
+	@Test
+	public void testG_CreateCategoryDuplicateNameShouldFail() {
+
+		assertThrows(
+				DataIntegrityViolationException.class, () -> {
+					categoryRepository.save(new Category("BAR"));
+					categoryRepository.save(new Category("BAR"));
+
+					categoryRepository.findAll().forEach(System.out::print);
+				});
+
+	}
+
+	//////////////////////////////
+
+	@Test
+	public void testH_CreateBookWithAuthor() {
+
+		Author authorA = authorRepository.save(new Author("Fan", "Tasy"));
+
+		Book bookA = bookRepository.save(new Book(
+				"Bloody Chamber",
+				authorA,
+				1979,
+				"4343434-14",
+				new BigDecimal("18.00"),
+				null,
+				true
+				)
+				);
+
+		assertThat(bookRepository.findById(bookA.getId())).isNotNull();
+	}
+
+	@Test
+	public void testI_CreateNewBookWithoutAuthor() {
+
+		Book bookA = bookRepository.save(new Book(
+				"Bloody Chamber",
+				null,
+				1979,
+				"4343434-15",
+				new BigDecimal("18.00"),
+				null,
+				true
+				)
+				);
+
+		assertThat(bookRepository.findById(bookA.getId())).isNotNull();
+
+	}
+
+	@Test
+	public void testJ_CreateBookWithCategory() {
+
+		Category categoryA = categoryRepository.save(new Category("Technology"));
+
+		Book bookA = bookRepository.save(new Book(
+				"Innovations in the era of information technology",
+				null,
+				1954,
+				"7575757-15",
+				new BigDecimal("43.22"),
+				categoryA,
+				true
+				)
+				);
+
+		assertThat(bookRepository.findById(bookA.getId())).isNotNull();
+
+	}
+	/*
+	@Test
+	public void testK_CreateBookWithoutCategory() {
+
+	}
+	 */
+	//////////////////////////////
+
+	@Test
+	public void testL_ExistingBookIsbnIsUnique() {
+
+		assertThrows(
+				DataIntegrityViolationException.class, () -> {
+
+					bookRepository.save(new Book(
+							"Exoplanets and Earth",
+							null,
+							2009,
+							"7575757-15",
+							new BigDecimal("43.22"),
+							null,
+							true
+							)
+							);
+
+					bookRepository.save(new Book(
+							"Interstellar research for astrobiological life",
+							null,
+							2006,
+							"7575757-15",
+							new BigDecimal("11.99"),
+							null,
+							false
+							)
+							);
+
+					bookRepository.findAll().forEach(System.out::print);
+				});
+
+	}
+
+	//////////////////////////////
+
+	@Test
+	public void testM_BookHashCanBeCreated() {
+
+		Book bookA = new Book(
+				"Exoplanets and Earth",
+				null,
+				2009,
+				"9191919-15",
+				new BigDecimal("43.22"),
+				null,
+				true
+				);
+
+		BookHash bookHashA = new BookHash();
+		bookHashA.setBook(bookA);
+		bookA.setBookHash(bookHashA);
+
+		bookRepository.save(bookA);
+		bookHashRepository.save(bookHashA);
+
+		assertThat(bookA).isNotNull();
+		assertThat(bookHashA).isNotNull();
+
+		assertThat(bookHashA.getBookId() == bookA.getId()).isEqualTo(true);
+		assertThat(bookHashA.getHashId().length() == 32).isEqualTo(true);
+
+		assertThat(bookHashA.getHashId().toString().matches("^[a-z0-9]*$")).isEqualTo(true);
+
+		assertThat(bookHashRepository.findByBookId(bookA.getId())).isNotNull();
+		assertThat(bookHashRepository.findByHashId(bookHashA.getHashId())).isNotNull();
+	}
+
+	@Test
+	public void testN_BookHashCanSetNewBookHashId() {
+
+		Book bookA = new Book(
+				"Exoplanets and Earth",
+				null,
+				2009,
+				"9191919-16",
+				new BigDecimal("43.22"),
+				null,
+				true
+				);
+
+		BookHash bookHashA = new BookHash();
+		bookHashA.setBook(bookA);
+		bookA.setBookHash(bookHashA);
+
+		bookRepository.save(bookA);
+		bookHashRepository.save(bookHashA);
+
+		String hashIdA = bookHashA.getHashId();
+		bookHashA.setHashId();
+		String hashIdB = bookHashA.getHashId();
+
+		bookHashRepository.save(bookHashA);
+
+		assertThat(bookHashA.getHashId().equals(hashIdA)).isEqualTo(false);
+
+	}
+
+	@Test
+	public void testO_BookHashCanNotDeleteBookId() {
+
+		assertThrows(
+				JpaSystemException.class, () -> {
+					Book bookA = new Book(
+							"Exoplanets and Earth",
+							null,
+							2009,
+							"9191919-17",
+							new BigDecimal("43.22"),
+							null,
+							true
+							);
+
+					BookHash bookHashA = new BookHash();
+					bookHashA.setBook(bookA);
+					bookA.setBookHash(bookHashA);
+
+					bookRepository.save(bookA);
+
+					bookHashA.setBookId(null);
+					bookHashRepository.save(bookHashA);
+					bookHashRepository.findAll().forEach(System.out::print);
+				});
+
+	}
+
+	//////////////////////////////
+
+	@Test
+	public void testP_DeleteAuthorBookHasAuthorConstraintShouldFail() {
+
+		assertThrows(
+				DataIntegrityViolationException.class, () -> {
+					Author authorA = authorRepository.save(new Author("Hor", "Ror"));
+
+					bookRepository.save(new Book(
+							"Twisted adventures in Elvenwood treehouse",
+							authorA,
+							2006,
+							"7575757-15",
+							new BigDecimal("11.99"),
+							null,
+							false
+							)
+							);
+
+					authorRepository.delete(authorA);
+					bookRepository.findAll().forEach(System.out::print);
+				});
+	}
+
+	@Test
+	public void testQ_DeleteCategoryBookHasCategoryConstraintShouldFail() {
+
+		assertThrows(
+				DataIntegrityViolationException.class, () -> {
+					Category categoryA = categoryRepository.save(new Category("Mystery"));
+
+					bookRepository.save(new Book(
+							"Ruins of Rkund",
+							null,
+							2009,
+							"7575757-15",
+							new BigDecimal("11.99"),
+							categoryA,
+							true
+							)
+							);
+
+					categoryRepository.delete(categoryA);
+					bookRepository.findAll().forEach(System.out::print);
+				});
+	}
+
+}
\ No newline at end of file