The main idea is exactly the same you saw in that previous chapter.

## Add tests for the SQL app

Let's update the example from [SQL (Relational) Databases](../tutorial/sql-databases.md){.internal-link target=_blank} to use a testing database.

All the app code is the same, you can go back to that chapter check how it was.

The only changes here are in the new testing file.

  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.sonatype.mavenbook.multi</groupId>
    <artifactId>simple-parent</artifactId>
  </parent>

  <artifactId>simple-webapp</artifactId>
  <name>Multi Chapter Simple Web Application Project</name>
  <dependencies>
    <dependency>
      <groupId>org.sonatype.mavenbook.multi</groupId>
      <artifactId>simple-weather</artifactId>
    </dependency>
  </dependencies>
  <build>

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// https://www.eclipse.org/jetty/documentation/current/alpn-chapter.html#alpn-versions
private fun alpnBootVersionForPatchVersion(patchVersion: Int): String? {
  return when (patchVersion) {
    in 0..24 -> "8.1.0.v20141016"
    in 25..30 -> "8.1.2.v20141202"

 */
package okhttp3.tls.internal.der

import java.net.ProtocolException

/**
 * Handles basic types that always use the same tag. This supports optional types and may set a type
 * hint for further adapters to process.
 *
 * Types like ANY and CHOICE that don't have a consistent tag cannot use this.
 */
internal data class BasicDerAdapter<T>(
  private val name: String,

  <parent>
    <groupId>org.sonatype.mavenbook.multi</groupId>
    <artifactId>parent</artifactId>
  </parent>
  <artifactId>simple-parent</artifactId>
  <packaging>pom</packaging>
  <name>Multi Chapter Simple Parent Project</name>

  <modules>
    <module>simple-weather</module>
    <module>simple-webapp</module>

    <!-- On purpose at the end, project graph is responsible for ordering -->

    Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

    But when the form includes files, it is encoded as `multipart/form-data`. You'll read about handling files in the next chapter.

 * limitations under the License.
 */
package okhttp3.tls.internal.der

import okio.ByteString

/**
 * A value whose type is not specified statically. Use this with [Adapters.any] which will attempt
 * to resolve a concrete type.
 */
internal data class AnyValue(
  var tagClass: Int,
  var tag: Long,
  var constructed: Boolean = false,
  var length: Long = -1L,

     * because we know that newClassMap() is implemented using ConstrainedMap which is itself
     * well-tested. A purist would object to this, but what can I say, we're dirty cheaters.
     */
    map.put(Integer.class, new Integer(5));
    assertThrows(ClassCastException.class, () -> map.put(Double.class, new Long(42)));
    // Won't compile: map.put(String.class, "x");
  }

     * because we know that newClassMap() is implemented using ConstrainedMap which is itself
     * well-tested. A purist would object to this, but what can I say, we're dirty cheaters.
     */
    map.put(Integer.class, new Integer(5));
    assertThrows(ClassCastException.class, () -> map.put(Double.class, new Long(42)));
    // Won't compile: map.put(String.class, "x");
  }

!!! info
    In this example we use invented custom headers `X-Key` and `X-Token`.

    But in real cases, when implementing security, you would get more benefits from using the integrated [Security utilities (the next chapter)](../security/index.md){.internal-link target=_blank}.

## Dependencies errors and return values

You can use the same dependency *functions* you use normally.

### Dependency requirements