[tests] rerun failed tests 2 times in CI (#1150)

* rerun failed tests 1 time

* Update main.yml

Author: timkpaine

.github/workflows/main.yml

@@ -31,7 +31,7 @@ jobs:
 
     - name: Create the conda environment
       shell: bash -l {0}
-      run: mamba install -q python=${{ matrix.python_version }} pip jupyterlab_pygments==0.1.0 pytest-cov nodejs yarn flake8 ipywidgets matplotlib xeus-cling openssl=1.1.1l "traitlets>=5.0.3,<6"
+      run: mamba install -q python=${{ matrix.python_version }} pip jupyterlab_pygments==0.1.0 pytest-cov pytest-rerunfailures nodejs yarn flake8 ipywidgets matplotlib xeus-cling openssl=1.1.1l "traitlets>=5.0.3,<6"
 
     - name: Install dependencies
       shell: bash -l {0}
@@ -46,7 +46,7 @@ jobs:
     - name: Run tests
       shell: bash -l {0}
       run: |
-        VOILA_TEST_XEUS_CLING=1 py.test tests/ --async-test-timeout=240
+        VOILA_TEST_XEUS_CLING=1 py.test tests/ --async-test-timeout=240 --reruns 2 --reruns-delay 1
         voila --help  # Making sure we can run `voila --help`
         # tests if voila sends a 'heartbeat' to avoid proxies from closing an apparently stale connection
         # Note that wget is the only easily available software that has a read-timeout
@@ -82,7 +82,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install jupyterlab_pygments==0.1.0 pytest-cov flake8 ipywidgets matplotlib traitlets
+          python -m pip install jupyterlab_pygments==0.1.0 pytest-cov pytest-rereunfailures flake8 ipywidgets matplotlib traitlets
           yarn install --network-timeout 100000
           python -m pip install ".[test]"
           cd tests/test_template
@@ -93,4 +93,4 @@ jobs:
       - name: Run test
         run: |
           set VOILA_TEST_DEBUG=1
-          py.test tests/ --async-test-timeout=240
+          py.test tests/ --async-test-timeout=240 --reruns 2 --reruns-delay 1

setup.cfg

@@ -53,6 +53,7 @@ test =
     matplotlib
     mock
     pytest
+    pytest-rerunfailures
     pytest-tornasync
 
 visual_test =