CI: Add the gametest

Author: YaLTeR

.github/workflows/gradle.yml

@@ -53,3 +53,23 @@ jobs:
           name: MouseTweaks-Fabric
           path: build/libs/
           if-no-files-found: error
+
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: ./.github/actions/setup
+
+      - name: Build testmod
+        run: ./gradlew --build-file build-fabric.gradle testmodClientClasses
+
+      - name: Run gametest
+        uses: GabrielBB/xvfb-action@v1
+        with:
+          run: ./gradlew --build-file build-fabric.gradle runClientGametest
+
+      - name: Upload screenshot
+        uses: actions/upload-artifact@v6
+        with:
+          name: screenshot
+          path: run/screenshots/
+          if-no-files-found: error