Tests cover the current implementation

Author: harawata

src/test/java/org/apache/ibatis/mapping/VendorDatabaseIdProviderTest.java

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+/*
+ *    Copyright 2009-2023 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+package org.apache.ibatis.mapping;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.sql.Connection;
+import java.sql.DatabaseMetaData;
+import java.sql.SQLException;
+import java.util.Properties;
+
+import javax.sql.DataSource;
+
+import org.junit.jupiter.api.Test;
+
+class VendorDatabaseIdProviderTest {
+
+  private static final String PRODUCT_NAME = "Chewbacca DB";
+
+  @Test
+  void shouldNpeBeThrownIfDataSourceIsNull() {
+    VendorDatabaseIdProvider provider = new VendorDatabaseIdProvider();
+    try {
+      provider.getDatabaseId(null);
+      fail("Should NullPointerException be thrown.");
+    } catch (NullPointerException e) {
+      // pass
+    }
+  }
+
+  @Test
+  void shouldProductNameBeReturnedIfPropertiesIsNull() throws Exception {
+    VendorDatabaseIdProvider provider = new VendorDatabaseIdProvider();
+    assertEquals(PRODUCT_NAME, provider.getDatabaseId(mockDataSource()));
+  }
+
+  @Test
+  void shouldProductNameBeTranslated() throws Exception {
+    VendorDatabaseIdProvider provider = new VendorDatabaseIdProvider();
+    Properties properties = new Properties();
+    String partialProductName = "Chewbacca";
+    String id = "chewie";
+    properties.put(partialProductName, id);
+    provider.setProperties(properties);
+    assertEquals(id, provider.getDatabaseId(mockDataSource()));
+  }
+
+  @Test
+  void shouldNullBeReturnedIfNoMatch() throws Exception {
+    VendorDatabaseIdProvider provider = new VendorDatabaseIdProvider();
+    Properties properties = new Properties();
+    properties.put("Ewok DB", "ewok");
+    provider.setProperties(properties);
+    assertNull(provider.getDatabaseId(mockDataSource()));
+  }
+
+  @Test
+  void shouldNullBeReturnedOnDbError() throws Exception {
+    DataSource dataSource = mock(DataSource.class);
+    when(dataSource.getConnection()).thenThrow(SQLException.class);
+
+    VendorDatabaseIdProvider provider = new VendorDatabaseIdProvider();
+    Properties properties = new Properties();
+    properties.put("Ewok DB", "ewok");
+    assertNull(provider.getDatabaseId(dataSource));
+  }
+
+  private DataSource mockDataSource() throws SQLException {
+    DatabaseMetaData metaData = mock(DatabaseMetaData.class);
+    when(metaData.getDatabaseProductName()).thenReturn(PRODUCT_NAME);
+    Connection connection = mock(Connection.class);
+    when(connection.getMetaData()).thenReturn(metaData);
+    DataSource dataSource = mock(DataSource.class);
+    when(dataSource.getConnection()).thenReturn(connection);
+    return dataSource;
+  }
+
+}