enable missing unit tests on circle CI

Created by: macjohnny

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• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
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  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh

  Commit all changed files. This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master. These must match the expectations made by your contribution. You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*. For Windows users, please run the script in Git BASH.
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.circleci/config.yml

@@ -10,7 +10,7 @@ jobs:
     machine:
       image: circleci/classic:latest
     working_directory: ~/OpenAPITools/openapi-generator
-    parallelism: 3
+    parallelism: 4
     shell: /bin/bash --login
     environment:
       CIRCLE_ARTIFACTS: /tmp/circleci-artifacts

CI/circle_parallel.sh

@@ -15,6 +15,12 @@ function cleanup {
 trap cleanup EXIT
 
 if [ "$NODE_INDEX" = "1" ]; then
+  echo "Running node $NODE_INDEX to test 'samples' defined in pom.xml ..."
+  java -version
+
+  mvn --no-snapshot-updates --quiet verify -Psamples -Dorg.slf4j.simpleLogger.defaultLogLevel=error
+
+elif [ "$NODE_INDEX" = "2" ]; then
   echo "Running node $NODE_INDEX to test 'samples.circleci' defined in pom.xml ..."
   java -version
 
@@ -23,7 +29,7 @@ if [ "$NODE_INDEX" = "1" ]; then
   echo "show ivy2 cache"
   ls -l /home/circleci/.ivy2/cache
 
-elif [ "$NODE_INDEX" = "2" ]; then
+elif [ "$NODE_INDEX" = "3" ]; then
   echo "Running node $NODE_INDEX to test haskell"
   # install haskell
   curl -sSL https://get.haskellstack.org/ | sh