refactor: rename and delete some patterns (#2970)

data-access-object/src/test/java/com/iluwatar/dao/AppTest.java

@@ -0,0 +1,46 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.dao;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+/**
+ * Tests that DAO example runs without errors.
+ */
+class AppTest {
+
+  /**
+   * Issue: Add at least one assertion to this test case.
+   * Solution: Inserted assertion to check whether the execution of the main method in {@link App#main(String[])}
+   * throws an exception.
+   */
+
+  @Test
+  void shouldExecuteDaoWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[]{}));
+  }
+}

data-access-object/src/test/java/com/iluwatar/dao/CustomerTest.java

@@ -0,0 +1,95 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.dao;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link Customer}.
+ */
+class CustomerTest {
+
+  private Customer customer;
+  private static final int ID = 1;
+  private static final String FIRSTNAME = "Winston";
+  private static final String LASTNAME = "Churchill";
+
+  @BeforeEach
+  void setUp() {
+    customer = new Customer(ID, FIRSTNAME, LASTNAME);
+  }
+
+  @Test
+  void getAndSetId() {
+    final var newId = 2;
+    customer.setId(newId);
+    assertEquals(newId, customer.getId());
+  }
+
+  @Test
+  void getAndSetFirstname() {
+    final var newFirstname = "Bill";
+    customer.setFirstName(newFirstname);
+    assertEquals(newFirstname, customer.getFirstName());
+  }
+
+  @Test
+  void getAndSetLastname() {
+    final var newLastname = "Clinton";
+    customer.setLastName(newLastname);
+    assertEquals(newLastname, customer.getLastName());
+  }
+
+  @Test
+  void notEqualWithDifferentId() {
+    final var newId = 2;
+    final var otherCustomer = new Customer(newId, FIRSTNAME, LASTNAME);
+    assertNotEquals(customer, otherCustomer);
+    assertNotEquals(customer.hashCode(), otherCustomer.hashCode());
+  }
+
+  @Test
+  void equalsWithSameObjectValues() {
+    final var otherCustomer = new Customer(ID, FIRSTNAME, LASTNAME);
+    assertEquals(customer, otherCustomer);
+    assertEquals(customer.hashCode(), otherCustomer.hashCode());
+  }
+
+  @Test
+  void equalsWithSameObjects() {
+    assertEquals(customer, customer);
+    assertEquals(customer.hashCode(), customer.hashCode());
+  }
+
+  @Test
+  void testToString() {
+    assertEquals(String.format("Customer(id=%s, firstName=%s, lastName=%s)",
+        customer.getId(), customer.getFirstName(), customer.getLastName()), customer.toString());
+  }
+}

data-access-object/src/test/java/com/iluwatar/dao/DbCustomerDaoTest.java

@@ -0,0 +1,263 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.dao;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import javax.sql.DataSource;
+import org.h2.jdbcx.JdbcDataSource;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+/**
+ * Tests {@link DbCustomerDao}.
+ */
+class DbCustomerDaoTest {
+
+  private static final String DB_URL = "jdbc:h2:mem:dao;DB_CLOSE_DELAY=-1";
+  private DbCustomerDao dao;
+  private final Customer existingCustomer = new Customer(1, "Freddy", "Krueger");
+
+  /**
+   * Creates customers schema.
+   *
+   * @throws SQLException if there is any error while creating schema.
+   */
+  @BeforeEach
+  void createSchema() throws SQLException {
+    try (var connection = DriverManager.getConnection(DB_URL);
+         var statement = connection.createStatement()) {
+      statement.execute(CustomerSchemaSql.CREATE_SCHEMA_SQL);
+    }
+  }
+
+  /**
+   * Represents the scenario where DB connectivity is present.
+   */
+  @Nested
+  class ConnectionSuccess {
+
+    /**
+     * Setup for connection success scenario.
+     *
+     * @throws Exception if any error occurs.
+     */
+    @BeforeEach
+    void setUp() throws Exception {
+      var dataSource = new JdbcDataSource();
+      dataSource.setURL(DB_URL);
+      dao = new DbCustomerDao(dataSource);
+      var result = dao.add(existingCustomer);
+      assertTrue(result);
+    }
+
+    /**
+     * Represents the scenario when DAO operations are being performed on a non-existing customer.
+     */
+    @Nested
+    class NonExistingCustomer {
+
+      @Test
+      void addingShouldResultInSuccess() throws Exception {
+        try (var allCustomers = dao.getAll()) {
+          assumeTrue(allCustomers.count() == 1);
+        }
+
+        final var nonExistingCustomer = new Customer(2, "Robert", "Englund");
+        var result = dao.add(nonExistingCustomer);
+        assertTrue(result);
+
+        assertCustomerCountIs(2);
+        assertEquals(nonExistingCustomer, dao.getById(nonExistingCustomer.getId()).get());
+      }
+
+      @Test
+      void deletionShouldBeFailureAndNotAffectExistingCustomers() throws Exception {
+        final var nonExistingCustomer = new Customer(2, "Robert", "Englund");
+        var result = dao.delete(nonExistingCustomer);
+
+        assertFalse(result);
+        assertCustomerCountIs(1);
+      }
+
+      @Test
+      void updationShouldBeFailureAndNotAffectExistingCustomers() throws Exception {
+        final var nonExistingId = getNonExistingCustomerId();
+        final var newFirstname = "Douglas";
+        final var newLastname = "MacArthur";
+        final var customer = new Customer(nonExistingId, newFirstname, newLastname);
+        var result = dao.update(customer);
+
+        assertFalse(result);
+        assertFalse(dao.getById(nonExistingId).isPresent());
+      }
+
+      @Test
+      void retrieveShouldReturnNoCustomer() throws Exception {
+        assertFalse(dao.getById(getNonExistingCustomerId()).isPresent());
+      }
+    }
+
+    /**
+     * Represents a scenario where DAO operations are being performed on an already existing
+     * customer.
+     */
+    @Nested
+    class ExistingCustomer {
+
+      @Test
+      void addingShouldResultInFailureAndNotAffectExistingCustomers() throws Exception {
+        var existingCustomer = new Customer(1, "Freddy", "Krueger");
+        var result = dao.add(existingCustomer);
+
+        assertFalse(result);
+        assertCustomerCountIs(1);
+        assertEquals(existingCustomer, dao.getById(existingCustomer.getId()).get());
+      }
+
+      @Test
+      void deletionShouldBeSuccessAndCustomerShouldBeNonAccessible() throws Exception {
+        var result = dao.delete(existingCustomer);
+
+        assertTrue(result);
+        assertCustomerCountIs(0);
+        assertFalse(dao.getById(existingCustomer.getId()).isPresent());
+      }
+
+      @Test
+      void updationShouldBeSuccessAndAccessingTheSameCustomerShouldReturnUpdatedInformation() throws
+          Exception {
+        final var newFirstname = "Bernard";
+        final var newLastname = "Montgomery";
+        final var customer = new Customer(existingCustomer.getId(), newFirstname, newLastname);
+        var result = dao.update(customer);
+
+        assertTrue(result);
+
+        final var cust = dao.getById(existingCustomer.getId()).get();
+        assertEquals(newFirstname, cust.getFirstName());
+        assertEquals(newLastname, cust.getLastName());
+      }
+    }
+  }
+
+  /**
+   * Represents a scenario where DB connectivity is not present due to network issue, or DB service
+   * unavailable.
+   */
+  @Nested
+  class ConnectivityIssue {
+
+    private static final String EXCEPTION_CAUSE = "Connection not available";
+
+    /**
+     * setup a connection failure scenario.
+     *
+     * @throws SQLException if any error occurs.
+     */
+    @BeforeEach
+    void setUp() throws SQLException {
+      dao = new DbCustomerDao(mockedDatasource());
+    }
+
+    private DataSource mockedDatasource() throws SQLException {
+      var mockedDataSource = mock(DataSource.class);
+      var mockedConnection = mock(Connection.class);
+      var exception = new SQLException(EXCEPTION_CAUSE);
+      doThrow(exception).when(mockedConnection).prepareStatement(Mockito.anyString());
+      doReturn(mockedConnection).when(mockedDataSource).getConnection();
+      return mockedDataSource;
+    }
+
+    @Test
+    void addingACustomerFailsWithExceptionAsFeedbackToClient() {
+      assertThrows(Exception.class, () -> dao.add(new Customer(2, "Bernard", "Montgomery")));
+    }
+
+    @Test
+    void deletingACustomerFailsWithExceptionAsFeedbackToTheClient() {
+      assertThrows(Exception.class, () -> dao.delete(existingCustomer));
+    }
+
+    @Test
+    void updatingACustomerFailsWithFeedbackToTheClient() {
+      final var newFirstname = "Bernard";
+      final var newLastname = "Montgomery";
+      assertThrows(Exception.class, () -> dao.update(new Customer(existingCustomer.getId(), newFirstname, newLastname)));
+    }
+
+    @Test
+    void retrievingACustomerByIdFailsWithExceptionAsFeedbackToClient() {
+      assertThrows(Exception.class, () -> dao.getById(existingCustomer.getId()));
+    }
+
+    @Test
+    void retrievingAllCustomersFailsWithExceptionAsFeedbackToClient() {
+      assertThrows(Exception.class, () -> dao.getAll());
+    }
+
+  }
+
+  /**
+   * Delete customer schema for fresh setup per test.
+   *
+   * @throws SQLException if any error occurs.
+   */
+  @AfterEach
+  void deleteSchema() throws SQLException {
+    try (var connection = DriverManager.getConnection(DB_URL);
+         var statement = connection.createStatement()) {
+      statement.execute(CustomerSchemaSql.DELETE_SCHEMA_SQL);
+    }
+  }
+
+  private void assertCustomerCountIs(int count) throws Exception {
+    try (var allCustomers = dao.getAll()) {
+      assertEquals(count, allCustomers.count());
+    }
+  }
+
+  /**
+   * An arbitrary number which does not correspond to an active Customer id.
+   *
+   * @return an int of a customer id which doesn't exist
+   */
+  private int getNonExistingCustomerId() {
+    return 999;
+  }
+}

data-access-object/src/test/java/com/iluwatar/dao/InMemoryCustomerDaoTest.java

@@ -0,0 +1,161 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.dao;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests {@link InMemoryCustomerDao}.
+ */
+class InMemoryCustomerDaoTest {
+
+  private InMemoryCustomerDao dao;
+  private static final Customer CUSTOMER = new Customer(1, "Freddy", "Krueger");
+
+  @BeforeEach
+  void setUp() {
+    dao = new InMemoryCustomerDao();
+    assertTrue(dao.add(CUSTOMER));
+  }
+
+  /**
+   * Represents the scenario when the DAO operations are being performed on a non-existent
+   * customer.
+   */
+  @Nested
+  class NonExistingCustomer {
+
+    @Test
+    void addingShouldResultInSuccess() throws Exception {
+      try (var allCustomers = dao.getAll()) {
+        assumeTrue(allCustomers.count() == 1);
+      }
+
+      final var nonExistingCustomer = new Customer(2, "Robert", "Englund");
+      var result = dao.add(nonExistingCustomer);
+      assertTrue(result);
+
+      assertCustomerCountIs(2);
+      assertEquals(nonExistingCustomer, dao.getById(nonExistingCustomer.getId()).get());
+    }
+
+    @Test
+    void deletionShouldBeFailureAndNotAffectExistingCustomers() throws Exception {
+      final var nonExistingCustomer = new Customer(2, "Robert", "Englund");
+      var result = dao.delete(nonExistingCustomer);
+
+      assertFalse(result);
+      assertCustomerCountIs(1);
+    }
+
+    @Test
+    void updateShouldBeFailureAndNotAffectExistingCustomers() {
+      final var nonExistingId = getNonExistingCustomerId();
+      final var newFirstname = "Douglas";
+      final var newLastname = "MacArthur";
+      final var customer = new Customer(nonExistingId, newFirstname, newLastname);
+      var result = dao.update(customer);
+
+      assertFalse(result);
+      assertFalse(dao.getById(nonExistingId).isPresent());
+    }
+
+    @Test
+    void retrieveShouldReturnNoCustomer() throws Exception {
+      assertFalse(dao.getById(getNonExistingCustomerId()).isPresent());
+    }
+  }
+
+  /**
+   * Represents the scenario when the DAO operations are being performed on an already existing
+   * customer.
+   */
+  @Nested
+  class ExistingCustomer {
+
+    @Test
+    void addingShouldResultInFailureAndNotAffectExistingCustomers() throws Exception {
+      var result = dao.add(CUSTOMER);
+
+      assertFalse(result);
+      assertCustomerCountIs(1);
+      assertEquals(CUSTOMER, dao.getById(CUSTOMER.getId()).get());
+    }
+
+    @Test
+    void deletionShouldBeSuccessAndCustomerShouldBeNonAccessible() throws Exception {
+      var result = dao.delete(CUSTOMER);
+
+      assertTrue(result);
+      assertCustomerCountIs(0);
+      assertFalse(dao.getById(CUSTOMER.getId()).isPresent());
+    }
+
+    @Test
+    void updationShouldBeSuccessAndAccessingTheSameCustomerShouldReturnUpdatedInformation() throws
+        Exception {
+      final var newFirstname = "Bernard";
+      final var newLastname = "Montgomery";
+      final var customer = new Customer(CUSTOMER.getId(), newFirstname, newLastname);
+      var result = dao.update(customer);
+
+      assertTrue(result);
+
+      final var cust = dao.getById(CUSTOMER.getId()).get();
+      assertEquals(newFirstname, cust.getFirstName());
+      assertEquals(newLastname, cust.getLastName());
+    }
+
+    @Test
+    void retriveShouldReturnTheCustomer() {
+      var optionalCustomer = dao.getById(CUSTOMER.getId());
+
+      assertTrue(optionalCustomer.isPresent());
+      assertEquals(CUSTOMER, optionalCustomer.get());
+    }
+  }
+
+  /**
+   * An arbitrary number which does not correspond to an active Customer id.
+   *
+   * @return an int of a customer id which doesn't exist
+   */
+  private int getNonExistingCustomerId() {
+    return 999;
+  }
+
+  private void assertCustomerCountIs(int count) throws Exception {
+    try (var allCustomers = dao.getAll()) {
+      assertEquals(count, allCustomers.count());
+    }
+  }
+}