[FLINK-23375][connector/jdbc] Build JDBC test jar.
diff --git a/flink-connector-jdbc/pom.xml b/flink-connector-jdbc/pom.xml
index 4edd126..3c9dd1f 100644
--- a/flink-connector-jdbc/pom.xml
+++ b/flink-connector-jdbc/pom.xml
@@ -190,6 +190,18 @@
 					<reuseForks>false</reuseForks>
 				</configuration>
 			</plugin>
+
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-jar-plugin</artifactId>
+				<executions>
+					<execution>
+						<goals>
+							<goal>test-jar</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 </project>