Revert "Temporarily skip vstest (sonic-net#891)" (sonic-net#892)

This reverts commit 11c68d8.

.azure-pipelines/test-docker-sonic-vs-template.yml

@@ -67,6 +67,44 @@ jobs:
       sudo pip3 install pytest==4.6.2 attrs==19.1.0 exabgp==4.0.10 distro==1.5.0 docker>=4.4.1 redis==3.3.4 flaky==3.7.0 requests==2.31.0
     displayName: "Install dependencies"
 
+  - script: |
+      set -ex
+      sudo docker load -i $(Build.ArtifactStagingDirectory)/download/docker-sonic-vs.gz
+      docker ps
+      ip netns list
+      pushd sonic-swss/tests
+
+      # run pytests in sets of 20   
+      all_tests=$(ls test_*.py)
+      all_tests="${all_tests} p4rt"
+      test_set=()
+      for test in ${all_tests}; do
+        test_set+=("${test}")
+        if [ ${#test_set[@]} -ge 20 ]; then
+          test_name=$(echo "${test_set[0]}" | cut -d "." -f 1)
+          echo "${test_set[*]}" | xargs sudo py.test -v --force-flaky --junitxml="${test_name}_tr.xml" --keeptb --imgname=docker-sonic-vs:$(Build.DefinitionName).$(Build.BuildNumber)
+          container_count=$(docker ps -q -a | wc -l)
+          if [ ${container_count} -gt 0 ]; then
+            docker stop $(docker ps -q -a)
+            docker rm $(docker ps -q -a)
+          fi
+          test_set=()
+        fi
+      done
+      if [ ${#test_set[@]} -gt 0 ]; then
+        test_name=$(echo "${test_set[0]}" | cut -d "." -f 1)
+        echo "${test_set[*]}" | xargs sudo py.test -v --force-flaky --junitxml="${test_name}_tr.xml" --keeptb --imgname=docker-sonic-vs:$(Build.DefinitionName).$(Build.BuildNumber)
+        container_count=$(docker ps -q -a | wc -l)
+        if [ ${container_count} -gt 0 ]; then
+          docker stop $(docker ps -q -a)
+          docker rm $(docker ps -q -a)
+        fi
+      fi
+
+      rm -rf $(Build.ArtifactStagingDirectory)/download
+    displayName: "Run vs tests"
+    ${{ if ne(variables['Build.Reason'], 'PullRequest') }}:
+      continueOnError: true
 
   - task: PublishTestResults@2
     inputs: