GH-5765: documentation for testing RDF4J from developer perspective

- running the RDF4J workbench and Server in a Jetty container

Author: aschwarte10

site/content/documentation/developer/testing.md

@@ -0,0 +1,39 @@
+---
+title: "Testing"
+toc: true
+autonumbering: true
+---
+
+## Testing the RDF4J Workbench Locally
+
+### Build the project
+
+```sh
+mvn -Passembly package
+cd assembly/target
+unzip eclipse-rdf4j-*-sdk.zip
+cd eclipse-rdf4j-*-SNAPSHOT
+```
+
+
+### Run the workbench in Docker
+
+```sh
+docker run -d \
+    --name rdf4j \
+    --platform linux/amd64 \
+    --restart unless-stopped \
+    -p 8080:8080 \
+    -v "$(pwd)/war/rdf4j-server.war:/var/lib/jetty/webapps/rdf4j-server.war" \
+    -v "$(pwd)/war/rdf4j-workbench.war:/var/lib/jetty/webapps/rdf4j-workbench.war" \
+    -v rdf4j-data:/var/rdf4j \
+    jetty:12.1-jdk25-alpine \
+    --module=ee10-deploy
+```
+
+### Access
+
+| Application | URL |
+|---|---|
+| RDF4J Server | http://localhost:8080/rdf4j-server |
+| RDF4J Workbench | http://localhost:8080/rdf4j-workbench |