Fix resource leak in performQuery by using Consumer pattern

modules/clickhouse/src/test/java/org/testcontainers/clickhouse/ClickHouseContainerTest.java

@@ -3,11 +3,11 @@
 import com.clickhouse.client.api.Client;
 import com.clickhouse.client.api.data_formats.ClickHouseBinaryFormatReader;
 import com.clickhouse.client.api.query.QueryResponse;
+import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Test;
 import org.testcontainers.ClickhouseTestImages;
 import org.testcontainers.db.AbstractContainerDatabaseTest;
 
-import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
@@ -26,10 +26,7 @@ void testSimple() throws SQLException {
         ) {
             clickhouse.start();
 
-            ResultSet resultSet = performQuery(clickhouse, "SELECT 1");
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).isEqualTo(1);
+            executeSelectOneQuery(clickhouse);
         }
     }
 
@@ -45,13 +42,18 @@ void customCredentialsWithUrlParams() throws SQLException {
         ) {
             clickhouse.start();
 
-            ResultSet resultSet = performQuery(
+            executeQuery(
                 clickhouse,
-                "SELECT value FROM system.settings where name='max_result_rows'"
+                "SELECT value FROM system.settings where name='max_result_rows'",
+                resultSet -> {
+                    Assertions
+                        .assertThatNoException()
+                        .isThrownBy(() -> {
+                            int resultSetInt = resultSet.getInt(1);
+                            assertThat(resultSetInt).isEqualTo(5);
+                        });
+                }
             );
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).isEqualTo(5);
         }
     }
 
@@ -60,10 +62,7 @@ void testNewAuth() throws SQLException {
         try (ClickHouseContainer clickhouse = new ClickHouseContainer(ClickhouseTestImages.CLICKHOUSE_24_12_IMAGE)) {
             clickhouse.start();
 
-            ResultSet resultSet = performQuery(clickhouse, "SELECT 1");
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).isEqualTo(1);
+            executeSelectOneQuery(clickhouse);
         }
     }
 

modules/clickhouse/src/test/java/org/testcontainers/junit/clickhouse/SimpleClickhouseTest.java

@@ -5,22 +5,16 @@
 import org.testcontainers.containers.ClickHouseContainer;
 import org.testcontainers.db.AbstractContainerDatabaseTest;
 
-import java.sql.ResultSet;
 import java.sql.SQLException;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
 class SimpleClickhouseTest extends AbstractContainerDatabaseTest {
 
     @Test
-    public void testSimple() throws SQLException {
+    void testSimple() throws SQLException {
         try (ClickHouseContainer clickhouse = new ClickHouseContainer(ClickhouseTestImages.CLICKHOUSE_IMAGE)) {
             clickhouse.start();
 
-            ResultSet resultSet = performQuery(clickhouse, "SELECT 1");
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).as("A basic SELECT query succeeds").isEqualTo(1);
+            executeSelectOneQuery(clickhouse);
         }
     }
 }

modules/cockroachdb/src/test/java/org/testcontainers/cockroachdb/CockroachContainerTest.java

@@ -5,7 +5,6 @@
 import org.testcontainers.db.AbstractContainerDatabaseTest;
 import org.testcontainers.images.builder.Transferable;
 
-import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.logging.Level;
 import java.util.logging.LogManager;
@@ -26,11 +25,7 @@ void testSimple() throws SQLException {
             // }
         ) {
             cockroach.start();
-
-            ResultSet resultSet = performQuery(cockroach, "SELECT 1");
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).as("A basic SELECT query succeeds").isEqualTo(1);
+            executeSelectOneQuery(cockroach);
         }
     }
 
@@ -42,10 +37,7 @@ void testExplicitInitScript() throws SQLException {
         ) { // CockroachDB is expected to be compatible with Postgres
             cockroach.start();
 
-            ResultSet resultSet = performQuery(cockroach, "SELECT foo FROM bar");
-
-            String firstColumnValue = resultSet.getString(1);
-            assertThat(firstColumnValue).as("Value from init script should equal real value").isEqualTo("hello world");
+            executeSelectFooBarQuery(cockroach);
         }
     }
 
@@ -80,10 +72,7 @@ void testWithUsernamePasswordDatabase() throws SQLException {
         ) {
             cockroach.start();
 
-            ResultSet resultSet = performQuery(cockroach, "SELECT 1");
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).as("A basic SELECT query succeeds").isEqualTo(1);
+            executeSelectOneQuery(cockroach);
 
             String jdbcUrl = cockroach.getJdbcUrl();
             assertThat(jdbcUrl).contains("/" + "test_database");
@@ -123,10 +112,7 @@ void testInitializationScript() throws SQLException {
         ) { // CockroachDB is expected to be compatible with Postgres
             cockroach.start();
 
-            ResultSet resultSet = performQuery(cockroach, "SELECT foo FROM bar");
-
-            String firstColumnValue = resultSet.getString(1);
-            assertThat(firstColumnValue).as("Value from init script should equal real value").isEqualTo("hello world");
+            executeSelectFooBarQuery(cockroach);
         }
     }
 }

modules/cratedb/src/test/java/org/testcontainers/junit/cratedb/SimpleCrateDBTest.java

@@ -1,11 +1,11 @@
 package org.testcontainers.junit.cratedb;
 
+import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Test;
 import org.testcontainers.CrateDBTestImages;
 import org.testcontainers.cratedb.CrateDBContainer;
 import org.testcontainers.db.AbstractContainerDatabaseTest;
 
-import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.logging.Level;
 import java.util.logging.LogManager;
@@ -26,9 +26,7 @@ void testSimple() throws SQLException {
         ) {
             cratedb.start();
 
-            ResultSet resultSet = performQuery(cratedb, "SELECT 1");
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).as("A basic SELECT query succeeds").isEqualTo(1);
+            executeSelectOneQuery(cratedb);
             assertHasCorrectExposedAndLivenessCheckPorts(cratedb);
         }
     }
@@ -41,9 +39,18 @@ void testCommandOverride() throws SQLException {
         ) {
             cratedb.start();
 
-            ResultSet resultSet = performQuery(cratedb, "select name from sys.cluster");
-            String result = resultSet.getString(1);
-            assertThat(result).as("cluster name should be overridden").isEqualTo("testcontainers");
+            executeQuery(
+                cratedb,
+                "select name from sys.cluster",
+                resultSet -> {
+                    Assertions
+                        .assertThatNoException()
+                        .isThrownBy(() -> {
+                            String result = resultSet.getString(1);
+                            assertThat(result).as("cluster name should be overridden").isEqualTo("testcontainers");
+                        });
+                }
+            );
         }
     }
 
@@ -55,10 +62,7 @@ void testExplicitInitScript() throws SQLException {
         ) {
             cratedb.start();
 
-            ResultSet resultSet = performQuery(cratedb, "SELECT foo FROM bar");
-
-            String firstColumnValue = resultSet.getString(1);
-            assertThat(firstColumnValue).as("Value from init script should equal real value").isEqualTo("hello world");
+            executeSelectFooBarQuery(cratedb);
         }
     }
 

modules/databend/src/test/java/org/testcontainers/databend/DatabendContainerTest.java

@@ -3,11 +3,8 @@
 import org.junit.jupiter.api.Test;
 import org.testcontainers.db.AbstractContainerDatabaseTest;
 
-import java.sql.ResultSet;
 import java.sql.SQLException;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
 class DatabendContainerTest extends AbstractContainerDatabaseTest {
 
     @Test
@@ -18,10 +15,7 @@ void testSimple() throws SQLException {
         ) {
             databend.start();
 
-            ResultSet resultSet = performQuery(databend, "SELECT 1");
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).isEqualTo(1);
+            executeSelectOneQuery(databend);
         }
     }
 
@@ -35,10 +29,7 @@ void customCredentialsWithUrlParams() throws SQLException {
         ) {
             databend.start();
 
-            ResultSet resultSet = performQuery(databend, "SELECT 1;");
-
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).isEqualTo(1);
+            executeSelectOneQuery(databend);
         }
     }
 }

modules/db2/src/test/java/org/testcontainers/db2/Db2ContainerTest.java

@@ -4,7 +4,6 @@
 import org.testcontainers.Db2TestImages;
 import org.testcontainers.db.AbstractContainerDatabaseTest;
 
-import java.sql.ResultSet;
 import java.sql.SQLException;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -19,10 +18,8 @@ void testSimple() throws SQLException {
         ) {
             db2.start();
 
-            ResultSet resultSet = performQuery(db2, "SELECT 1 FROM SYSIBM.SYSDUMMY1");
+            executeSelectOneQuery(db2, "SELECT 1 FROM SYSIBM.SYSDUMMY1");
 
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).as("A basic SELECT query succeeds").isEqualTo(1);
             assertHasCorrectExposedAndLivenessCheckPorts(db2);
         }
     }
@@ -32,10 +29,8 @@ void testSimpleWithNewImage() throws SQLException {
         try (Db2Container db2 = new Db2Container("icr.io/db2_community/db2:11.5.8.0").acceptLicense()) {
             db2.start();
 
-            ResultSet resultSet = performQuery(db2, "SELECT 1 FROM SYSIBM.SYSDUMMY1");
+            executeSelectOneQuery(db2, "SELECT 1 FROM SYSIBM.SYSDUMMY1");
 
-            int resultSetInt = resultSet.getInt(1);
-            assertThat(resultSetInt).as("A basic SELECT query succeeds").isEqualTo(1);
             assertHasCorrectExposedAndLivenessCheckPorts(db2);
         }
     }

modules/jdbc-test/src/main/java/org/testcontainers/db/AbstractContainerDatabaseTest.java

@@ -2,27 +2,115 @@
 
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
+import org.assertj.core.api.Assertions;
 import org.testcontainers.containers.JdbcDatabaseContainer;
 
+import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.util.function.Consumer;
 
 import javax.sql.DataSource;
 
 public abstract class AbstractContainerDatabaseTest {
 
-    protected ResultSet performQuery(JdbcDatabaseContainer<?> container, String sql) throws SQLException {
-        DataSource ds = getDataSource(container);
-        Statement statement = ds.getConnection().createStatement();
-        statement.execute(sql);
-        ResultSet resultSet = statement.getResultSet();
+    protected void executeQuery(
+        final JdbcDatabaseContainer<?> container,
+        final String sql,
+        final Consumer<ResultSet> consumer
+    ) throws SQLException {
+        final DataSource ds = getDataSource(container);
 
-        resultSet.next();
-        return resultSet;
+        try (
+            Connection connection = ds.getConnection();
+            Statement statement = connection.createStatement();
+            ResultSet resultSet = statement.executeQuery(sql)
+        ) {
+            resultSet.next();
+            consumer.accept(resultSet);
+        }
     }
 
-    protected DataSource getDataSource(JdbcDatabaseContainer<?> container) {
+    protected void executeSelectOneQuery(final JdbcDatabaseContainer<?> container) throws SQLException {
+        executeSelectOneQuery(container, "SELECT 1");
+    }
+
+    protected void executeSelectOneQuery(final JdbcDatabaseContainer<?> container, final String sql)
+        throws SQLException {
+        executeQuery(
+            container,
+            sql,
+            resultSet -> {
+                Assertions
+                    .assertThatNoException()
+                    .isThrownBy(() -> {
+                        int resultSetInt = resultSet.getInt(1);
+                        Assertions.assertThat(resultSetInt).as("A basic SELECT query succeeds").isEqualTo(1);
+                    });
+            }
+        );
+    }
+
+    protected void executeSelectFooBarQuery(final JdbcDatabaseContainer<?> container) throws SQLException {
+        executeQuery(
+            container,
+            "SELECT foo FROM bar",
+            resultSet -> {
+                Assertions
+                    .assertThatNoException()
+                    .isThrownBy(() -> {
+                        String firstColumnValue = resultSet.getString(1);
+                        Assertions
+                            .assertThat(firstColumnValue)
+                            .as("Value from init script should equal real value")
+                            .isEqualTo("hello world");
+                    });
+            }
+        );
+    }
+
+    protected void executeSelectMaxConnectionsQuery(
+        final JdbcDatabaseContainer<?> container,
+        final String expectedMaxConnections
+    ) throws SQLException {
+        executeQuery(
+            container,
+            "SELECT current_setting('max_connections')",
+            resultSet -> {
+                Assertions
+                    .assertThatNoException()
+                    .isThrownBy(() -> {
+                        String result = resultSet.getString(1);
+                        Assertions
+                            .assertThat(result)
+                            .as("max_connections should be overridden")
+                            .isEqualTo(expectedMaxConnections);
+                    });
+            }
+        );
+    }
+
+    protected void executeSelectVersionQuery(final JdbcDatabaseContainer<?> container, final String expectedVersion)
+        throws SQLException {
+        executeQuery(
+            container,
+            "SELECT VERSION()",
+            resultSet -> {
+                Assertions
+                    .assertThatNoException()
+                    .isThrownBy(() -> {
+                        String resultSetString = resultSet.getString(1);
+                        Assertions
+                            .assertThat(resultSetString)
+                            .as("The database version can be set using a container rule parameter")
+                            .startsWith(expectedVersion);
+                    });
+            }
+        );
+    }
+
+    protected DataSource getDataSource(final JdbcDatabaseContainer<?> container) {
         HikariConfig hikariConfig = new HikariConfig();
         hikariConfig.setJdbcUrl(container.getJdbcUrl());
         hikariConfig.setUsername(container.getUsername());