Test OpenCV.js (#174)

* Build OpenCV.js

* Run tests

* Use nigthly docs for JS tests

* Custom branch

* Update OCV-Nightly-docs-js.yaml

.github/workflows/OCV-Nightly-docs-js.yaml

@@ -48,7 +48,14 @@ jobs:
       timeout-minutes: 60
       run: |
         cd $HOME/build
-        python ../opencv/platforms/js/build_js.py js
+        emcmake python ../opencv/platforms/js/build_js.py js --build_test
+    - name: Run js tests
+      timeout-minutes: 60
+      if: ${{ always() && matrix.branch == '4.x' }}
+      run: |
+        cd $HOME/build/js/bin
+        npm install
+        node tests.js
     - name: Configure OpenCV doxygen
       timeout-minutes: 60
       run: |
@@ -72,4 +79,4 @@ jobs:
       uses: actions/upload-artifact@v3
       with:
         name: OpenCVDocDoxygen${{ matrix.branch }}
-        path: /home/ci/build/release/doc_doxygen.zip
+        path: /home/ci/build/release/doc_doxygen.zip