diff --git a/src/main/java/org/itsallcode/jdbc/statement/ConvertingPreparedStatement.java b/src/main/java/org/itsallcode/jdbc/statement/ConvertingPreparedStatement.java
index 813730c..3be676b 100644
--- a/src/main/java/org/itsallcode/jdbc/statement/ConvertingPreparedStatement.java
+++ b/src/main/java/org/itsallcode/jdbc/statement/ConvertingPreparedStatement.java
@@ -5,10 +5,20 @@
 
 import org.itsallcode.jdbc.ParameterMapper;
 
+/**
+ * A {@link PreparedStatement} that delegates all methods and converts parameter
+ * value of {@link #convert(Object)} using a {@link ParameterMapper}.
+ */
 public class ConvertingPreparedStatement extends DelegatingPreparedStatement {
 
     private final ParameterMapper parameterMapper;
 
+    /**
+     * Create a new instance.
+     * 
+     * @param delegate        delegate
+     * @param parameterMapper parameter mapper
+     */
     public ConvertingPreparedStatement(final PreparedStatement delegate, final ParameterMapper parameterMapper) {
         super(delegate);
         this.parameterMapper = parameterMapper;
diff --git a/src/test/java/org/itsallcode/jdbc/statement/ConvertingPreparedStatementTest.java b/src/test/java/org/itsallcode/jdbc/statement/ConvertingPreparedStatementTest.java
new file mode 100644
index 0000000..3380f5a
--- /dev/null
+++ b/src/test/java/org/itsallcode/jdbc/statement/ConvertingPreparedStatementTest.java
@@ -0,0 +1,33 @@
+package org.itsallcode.jdbc.statement;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.same;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+import org.itsallcode.jdbc.ParameterMapper;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class ConvertingPreparedStatementTest {
+    @Mock
+    PreparedStatement delegateMock;
+    @Mock
+    ParameterMapper parameterMapperMock;
+
+    @SuppressWarnings("resource")
+    @Test
+    void setObject() throws SQLException {
+        final Object o1 = new Object();
+        final Object o2 = new Object();
+        when(parameterMapperMock.map(same(o1))).thenReturn(o2);
+        new ConvertingPreparedStatement(delegateMock, parameterMapperMock).setObject(1, o1);
+        verify(delegateMock).setObject(eq(1), same(o2));
+    }
+}