Fix init script decoding with configurable charsets

docs/modules/databases/jdbc.md

@@ -174,3 +174,17 @@ Examples/Tests:
 
  * [MySQL](https://github.com/testcontainers/testcontainers-java/blob/main/modules/mysql/src/test/java/org/testcontainers/junit/mysql/SimpleMySQLTest.java)
  * [PostgreSQL](https://github.com/testcontainers/testcontainers-java/blob/main/modules/postgresql/src/test/java/org/testcontainers/junit/postgresql/SimplePostgreSQLTest.java)
+
+## Init script encoding for container instances
+
+Scripts configured with `withInitScript` or `withInitScripts` are read as UTF-8 by default.
+For scripts saved with another encoding, set the charset on the container before starting it:
+
+```java
+container.withInitScript("init.sql")
+    .withInitScriptCharset(java.nio.charset.Charset.forName("windows-1252"));
+```
+
+The charset applies to all scripts configured on that container. It controls how the script files
+are read, not the database's character set. Scripts loaded through the JDBC URL parameter
+`TC_INITSCRIPT` continue to use UTF-8.

modules/database-commons/src/main/java/org/testcontainers/ext/ScriptUtils.java

@@ -24,6 +24,7 @@
 
 import java.io.IOException;
 import java.net.URL;
+import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.LinkedList;
 import java.util.List;
@@ -192,12 +193,24 @@ public static boolean containsSqlScriptDelimiters(
     }
 
     /**
-     * Load script from classpath and apply it to the given database
+     * Load a UTF-8 script from the classpath and apply it to the given database.
      *
      * @param databaseDelegate database delegate for script execution
      * @param initScriptPath   the resource to load the init script from
      */
     public static void runInitScript(DatabaseDelegate databaseDelegate, String initScriptPath) {
+        runInitScript(databaseDelegate, initScriptPath, StandardCharsets.UTF_8);
+    }
+
+    /**
+     * Load a script from the classpath using the given charset and apply it to the given database.
+     *
+     * @param databaseDelegate database delegate for script execution
+     * @param initScriptPath the resource to load the init script from
+     * @param charset the charset used to read the script; never {@code null}
+     */
+    public static void runInitScript(DatabaseDelegate databaseDelegate, String initScriptPath, Charset charset) {
+        checkArgument(charset != null, "charset must not be null");
         try {
             URL resource = Thread.currentThread().getContextClassLoader().getResource(initScriptPath);
             if (resource == null) {
@@ -209,7 +222,7 @@ public static void runInitScript(DatabaseDelegate databaseDelegate, String initS
                     );
                 }
             }
-            String scripts = IOUtils.toString(resource, StandardCharsets.UTF_8);
+            String scripts = IOUtils.toString(resource, charset);
             executeDatabaseScript(databaseDelegate, initScriptPath, scripts);
         } catch (IOException e) {
             LOGGER.warn("Could not load classpath init script: {}", initScriptPath);

modules/database-commons/src/test/java/org/testcontainers/ext/ScriptUtilsTest.java

@@ -0,0 +1,69 @@
+package org.testcontainers.ext;
+
+import org.junit.jupiter.api.Test;
+import org.testcontainers.delegate.AbstractDatabaseDelegate;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class ScriptUtilsTest {
+
+    private final RecordingDatabaseDelegate delegate = new RecordingDatabaseDelegate();
+
+    @Test
+    void usesUtf8ByDefault() {
+        ScriptUtils.runInitScript(delegate, "init-utf-8.sql");
+
+        assertThat(delegate.statements).containsExactly("SELECT 'café'");
+    }
+
+    @Test
+    void readsWindows1252Script() {
+        ScriptUtils.runInitScript(delegate, "init-windows-1252.sql", Charset.forName("windows-1252"));
+
+        assertThat(delegate.statements).containsExactly("SELECT 'café'");
+    }
+
+    @Test
+    void readsExplicitUtf8Script() {
+        ScriptUtils.runInitScript(delegate, "init-utf-8.sql", StandardCharsets.UTF_8);
+
+        assertThat(delegate.statements).containsExactly("SELECT 'café'");
+    }
+
+    @Test
+    void rejectsNullCharset() {
+        assertThatThrownBy(() -> ScriptUtils.runInitScript(delegate, "init-utf-8.sql", null))
+            .isInstanceOf(IllegalArgumentException.class)
+            .hasMessage("charset must not be null");
+    }
+
+    private static class RecordingDatabaseDelegate extends AbstractDatabaseDelegate<Void> {
+
+        private final List<String> statements = new ArrayList<>();
+
+        @Override
+        public void execute(
+            String statement,
+            String scriptPath,
+            int lineNumber,
+            boolean continueOnError,
+            boolean ignoreFailedDrops
+        ) {
+            statements.add(statement);
+        }
+
+        @Override
+        protected Void createNewConnection() {
+            return null;
+        }
+
+        @Override
+        protected void closeConnectionQuietly(Void connection) {}
+    }
+}

modules/database-commons/src/test/resources/init-utf-8.sql

@@ -0,0 +1 @@
+SELECT 'café';

modules/database-commons/src/test/resources/init-windows-1252.sql

@@ -0,0 +1 @@
+SELECT 'caf�';

modules/jdbc/src/main/java/org/testcontainers/containers/JdbcDatabaseContainer.java

@@ -13,6 +13,8 @@
 import org.testcontainers.utility.DockerImageName;
 import org.testcontainers.utility.MountableFile;
 
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.sql.Connection;
 import java.sql.Driver;
 import java.sql.SQLException;
@@ -41,6 +43,8 @@ public abstract class JdbcDatabaseContainer<SELF extends JdbcDatabaseContainer<S
 
     private List<String> initScriptPaths = new ArrayList<>();
 
+    private Charset initScriptCharset = StandardCharsets.UTF_8;
+
     protected Map<String, String> parameters = new HashMap<>();
 
     protected Map<String, String> urlParameters = new HashMap<>();
@@ -171,6 +175,18 @@ public SELF withInitScripts(Iterable<String> initScriptPaths) {
         return self();
     }
 
+    /**
+     * Sets the charset used to read all scripts configured with {@link #withInitScript(String)}
+     * or {@link #withInitScripts(String...)}. Defaults to UTF-8.
+     *
+     * @param charset the charset used to read the scripts
+     * @return self
+     */
+    public SELF withInitScriptCharset(@NonNull Charset charset) {
+        this.initScriptCharset = charset;
+        return self();
+    }
+
     @SneakyThrows(InterruptedException.class)
     @Override
     protected void waitUntilContainerStarted() {
@@ -365,7 +381,7 @@ protected void runInitScriptIfRequired() {
         initScriptPaths
             .stream()
             .filter(Objects::nonNull)
-            .forEach(path -> ScriptUtils.runInitScript(getDatabaseDelegate(), path));
+            .forEach(path -> ScriptUtils.runInitScript(getDatabaseDelegate(), path, initScriptCharset));
     }
 
     public void setParameters(Map<String, String> parameters) {

modules/jdbc/src/test/java/org/testcontainers/containers/JdbcDatabaseContainerTest.java

@@ -3,12 +3,18 @@
 import lombok.NonNull;
 import org.junit.jupiter.api.Test;
 import org.slf4j.Logger;
+import org.testcontainers.delegate.DatabaseDelegate;
 
+import java.nio.charset.Charset;
 import java.sql.Connection;
 import java.sql.SQLException;
+import java.util.Collections;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 class JdbcDatabaseContainerTest {
 
@@ -20,7 +26,56 @@ void anExceptionIsThrownIfJdbcIsNotAvailable() {
         assertThatExceptionOfType(IllegalStateException.class).isThrownBy(jdbcContainer::waitUntilContainerStarted);
     }
 
-    static class JdbcDatabaseContainerStub extends JdbcDatabaseContainer {
+    @Test
+    void readsInitScriptAsUtf8ByDefault() {
+        JdbcDatabaseContainerStub container = new JdbcDatabaseContainerStub("mysql:latest");
+        container.withInitScript("init-utf-8.sql");
+
+        container.runInitScriptIfRequired();
+
+        verify(container.delegate).execute(Collections.singletonList("SELECT 'café'"), "init-utf-8.sql", false, false);
+    }
+
+    @Test
+    void readsInitScriptWithConfiguredCharset() {
+        JdbcDatabaseContainerStub container = new JdbcDatabaseContainerStub("mysql:latest");
+        assertThat(container.withInitScriptCharset(Charset.forName("windows-1252"))).isSameAs(container);
+        container.withInitScript("init-windows-1252.sql");
+
+        container.runInitScriptIfRequired();
+
+        verify(container.delegate)
+            .execute(Collections.singletonList("SELECT 'café'"), "init-windows-1252.sql", false, false);
+    }
+
+    @Test
+    void readsAllInitScriptsWithConfiguredCharset() {
+        JdbcDatabaseContainerStub container = new JdbcDatabaseContainerStub("mysql:latest");
+        container
+            .withInitScripts("init-windows-1252.sql", null, "init-windows-1252.sql")
+            .withInitScriptCharset(Charset.forName("windows-1252"));
+
+        container.runInitScriptIfRequired();
+
+        verify(container.delegate, times(2))
+            .execute(Collections.singletonList("SELECT 'café'"), "init-windows-1252.sql", false, false);
+    }
+
+    @Test
+    void rejectsNullInitScriptCharset() {
+        JdbcDatabaseContainerStub container = new JdbcDatabaseContainerStub("mysql:latest");
+
+        assertThatExceptionOfType(NullPointerException.class).isThrownBy(() -> container.withInitScriptCharset(null));
+    }
+
+    static class JdbcDatabaseContainerStub extends JdbcDatabaseContainer<JdbcDatabaseContainerStub> {
+
+        private final DatabaseDelegate delegate = mock(DatabaseDelegate.class);
+
+        @Override
+        protected DatabaseDelegate getDatabaseDelegate() {
+            return delegate;
+        }
 
         public JdbcDatabaseContainerStub(@NonNull String dockerImageName) {
             super(dockerImageName);

modules/jdbc/src/test/resources/init-utf-8.sql

@@ -0,0 +1 @@
+SELECT 'café';

modules/jdbc/src/test/resources/init-windows-1252.sql

@@ -0,0 +1 @@
+SELECT 'caf�';