Demo Refactoring Unit Test Stage

In this guide, we’ll refactor our Jenkins pipeline so that the Unit Testing stage runs concurrently on Node.js 18, 19, and 20. This approach speeds up feedback and ensures compatibility across multiple runtime versions.

Table of Contents

• Initial Pipeline Configuration
• Adding Parallel Unit Tests
• [Understanding the Node 20 Failure](#understanding-the-node 20-failure)
• [Fixing Dependencies for Node 20](#fixing-dependencies-for-node 20)
• Complete Refactored Pipeline
• Links and References

Initial Pipeline Configuration

We start with a simple declarative pipeline using a Kubernetes agent that defaults to a Node 18 container. By default, all steps in the Unit Testing stage will run on Node 18.

@Library('dasher-trusted-shared-library@featureTrivyScan') _
pipeline {
  agent {
    kubernetes {
      cloud           'dasher-prod-k8s-us-east'
      yamlFile        'k8s-agent.yaml'
      defaultContainer 'node-18'
    }
  }

  tools {
    nodejs 'nodejs-22-6-0'
  }

  environment {
    MONGO_URI         = "mongodb+srv://supercluster.d8jjj.mongodb.net/superData"
    MONGO_DB_CREDS    = credentials('mongo-db-credentials')
    MONGO_DB_USERNAME = credentials('mongo-db-username')
    MONGO_PASSWORD    = credentials('mongo-db-password')
  }

  stages {
    stage('Unit Testing') {
      options { retry(2) }
      steps {
        sh 'node -v'
        sh 'npm test'
      }
    }
  }
}

Adding Parallel Unit Tests

To run tests on multiple Node.js versions simultaneously, we replace the single Unit Testing stage with parallel sub-stages:

pipeline {
  agent {
    kubernetes {
      cloud           'dasher-prod-k8s-us-east'
      yamlFile        'k8s-agent.yaml'
      defaultContainer 'node-18'
    }
  }

  tools {
    nodejs 'nodejs-22-6-0'
  }

  environment {
    MONGO_URI          = 'mongodb+srv://supercluster.d83jj.mongodb.net/superData'
    MONGO_DB_CREDENTIALS = credentials('mongo-db-credentials')
    MONGO_USERNAME     = credentials('mongo-db-username')
    MONGO_PASSWORD     = credentials('mongo-db-password')
    SONAR_SCANNER_HOME = tool 'sonar-scanner-610'
    GITEA_TOKEN        = credentials('gitea-api-token')
  }

  options {
    disableResume()
    disableConcurrentBuilds abortPrevious: true
  }

  stages {
    stage('Installing Dependencies') {
      options { timestamps() }
      steps {
        sh 'node -v'
        sh 'npm install --no-audit'
      }
    }

    stage('Dependency Scanning') {
      parallel {
        // other scanning stages...
      }
    }

    stage('Unit Testing') {
      parallel {
        stage('NodeJS 18') {
          options { retry(2) }
          steps {
            sh 'node -v'
            sh 'npm test'
          }
        }

        stage('NodeJS 19') {
          options { retry(2) }
          steps {
            container('node-19') {
              sh 'sleep 10s'     // avoid port conflicts
              sh 'node -v'
              sh 'npm test'
            }
          }
        }

        stage('NodeJS 20') {
          agent {
            docker {
              image 'node:20-alpine'
            }
          }
          options { retry(2) }
          steps {
            sh 'node -v'
            sh 'npm test'
          }
        }
      }
    }
  }
}

Understanding the Node 20 Failure

When the Node 20 stage runs as a separate Docker container, you might encounter:

> npm test
> Solar [email protected] test
> mocha app-test.js --timeout 10000 --reporter mocha-junit-reporter --exit

sh: mocha: not found
script returned exit code 127

The error occurs because npm install was only executed in the Kubernetes Pod (Node 18/19). The separate Node 20 container has no node_modules directory.

Fixing Dependencies for Node 20

Quick Fix: Inline npm install

Add the install step directly to the Node 20 stage:

stage('NodeJS 20') {
  agent {
    docker {
      image 'node:20-alpine'
    }
  }
  options { retry(2) }
  steps {
    sh 'npm install'
    sh 'node -v'
    sh 'npm test'
  }
}

Cleaner Approach: Separate Install & Test Sub-Stages

Within the parallel group for Node 20, create two sub-stages—one for installing dependencies, one for running tests:

stage('Unit Testing') {
  parallel {
    // NodeJS 18 & 19 as before...

    stage('NodeJS 20') {
      parallel {
        stage('Install Dependencies') {
          agent {
            docker {
              image 'node:20-alpine'
            }
          }
          steps {
            sh 'npm install'
          }
        }
        stage('Run Tests') {
          agent {
            docker {
              image 'node:20-alpine'
            }
          }
          options { retry(2) }
          steps {
            sh 'node -v'
            sh 'npm test'
          }
        }
      }
    }
  }
}

This structure ensures each Node.js container installs its own dependencies and runs tests in isolation.

Complete Refactored Pipeline

Putting it all together:

@Library('dasher-trusted-shared-library@featureTrivyScan') _
pipeline {
  agent {
    kubernetes {
      cloud           'dasher-prod-k8s-us-east'
      yamlFile        'k8s-agent.yaml'
      defaultContainer 'node-18'
    }
  }

  tools {
    nodejs 'nodejs-22-6-0'
  }

  environment {
    MONGO_URI           = 'mongodb+srv://supercluster.d83jj.mongodb.net/superData'
    MONGO_DB_CREDENTIALS= credentials('mongo-db-credentials')
    MONGO_USERNAME      = credentials('mongo-db-username')
    MONGO_PASSWORD      = credentials('mongo-db-password')
    SONAR_SCANNER_HOME  = tool 'sonar-scanner-610'
    GITEA_TOKEN         = credentials('gitea-api-token')
  }

  options {
    disableResume()
    disableConcurrentBuilds abortPrevious: true
  }

  stages {
    stage('Installing Dependencies') {
      steps {
        sh 'node -v'
        sh 'npm install --no-audit'
      }
    }

    stage('Dependency Scanning') {
      parallel {
        // other scanning stages...
      }
    }

    stage('Unit Testing') {
      parallel {
        stage('NodeJS 18') { /* ... */ }
        stage('NodeJS 19') { /* ... */ }
        stage('NodeJS 20') {
          parallel {
            stage('Install Dependencies') { /* ... */ }
            stage('Run Tests')           { /* ... */ }
          }
        }
      }
    }
  }
}

Links and References

• Jenkins Pipeline Documentation
• Kubernetes Plugin for Jenkins
• Node.js Official Docker Images
• Mocha Test Framework