JUnit test report publishing in Jenkins - Step-by-Step Execution

Process Flow - JUnit test report publishing

Start Pipeline

↓

Run mvn test

↓

Tests Execute

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Post: always

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junit step parses XML

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Reports visible in Jenkins UI

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Build marked stable/unstable

The pipeline runs Maven tests which generate JUnit XML reports. Regardless of pass or fail, the post/always block runs the junit step to parse XML reports and display results in Jenkins UI.

Execution Sample

Jenkins

pipeline {
  agent any
  stages {
    stage('Test') {
      steps {
        sh 'mvn test'
      }
    }
  }
  post {
    always {
      junit 'target/surefire-reports/*.xml'
    }
  }
}

This Jenkins pipeline runs Maven tests and publishes JUnit XML reports from surefire-reports directory using the post/always block.

Process Table

Step	Action	Workspace State	Reports State	Build Status	Next Step
1	Pipeline starts, agent allocated	Empty workspace checked out	No reports yet	In progress	Run tests
2	sh 'mvn test' executes	Source compiled, tests running	No reports yet	In progress	Tests complete
3	Maven Surefire generates XML reports	target/surefire-reports/*.xml created	XML files on disk (3 files)	In progress	Enter post block
4	post/always block triggers	Workspace unchanged	XML files on disk	In progress	Parse reports
5	junit step parses XML reports	Workspace unchanged	10 tests: 8 passed, 1 failed, 1 skipped	Unstable (has failures)	Display results
6	Test results visible in Jenkins UI	Workspace unchanged	Report published with trends	Unstable	Pipeline ends

💡 Reports published successfully. Build marked UNSTABLE due to 1 test failure.

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 5	Final
testsPassed	0	0	8	8	8
testsFailed	0	0	1	1	1
testsSkipped	0	0	1	1	1
reportsPublished	No	No	No	Yes	Yes
buildStatus	In progress	In progress	In progress	Unstable	Unstable

Key Moments - 3 Insights

Why use post/always instead of putting junit inside the Test stage steps?

If junit is inside steps and mvn test fails (non-zero exit), the stage aborts before reaching the junit step. Using post/always ensures reports are published regardless of test pass or fail.

What is the difference between UNSTABLE and FAILURE build status?

UNSTABLE means tests ran but some failed — the junit step sets this automatically. FAILURE means the pipeline itself crashed (e.g., syntax error, agent unavailable). Test failures produce UNSTABLE, not FAILURE.

Where do the XML report files come from?

Maven Surefire plugin generates JUnit-format XML files in target/surefire-reports/ automatically when running mvn test. The junit step reads these files — it does not run tests itself.

Visual Quiz - 3 Questions

Look at the execution table. At which step do XML report files first appear on disk?

A Step 1 — when the agent is allocated

B Step 2 — when mvn test runs

C Step 3 — when Surefire generates reports

D Step 5 — when junit step parses them

💡 Hint

Check the Reports State column — reports appear after Maven finishes running tests.

From the variable tracker, what is the build status after the junit step parses the reports?

A Success

B Failure

C Unstable

D In progress

💡 Hint

Check the buildStatus row after Step 5 — failed tests cause UNSTABLE, not FAILURE.

What would happen if the junit path pattern 'target/surefire-reports/*.xml' matched zero files?

A Jenkins publishes an empty report with 0 tests

B Jenkins throws an error: No test report files found

C Jenkins skips report publishing silently

D Jenkins marks the build as SUCCESS

💡 Hint

The junit step requires at least one matching file — use allowEmptyResults: true to handle missing reports gracefully.

Concept Snapshot

JUnit test report publishing makes test results visible in Jenkins UI.
Maven Surefire generates XML reports in target/surefire-reports/.
The junit pipeline step parses XML files — it does not run tests.
Always use post/always to ensure reports publish even on failure.
Failed tests set build to UNSTABLE, not FAILURE.
Use allowEmptyResults: true if reports might not exist.

Full Transcript

This visual execution shows how Jenkins publishes JUnit test reports. The pipeline runs mvn test which executes unit tests. Maven Surefire plugin generates XML report files in the target/surefire-reports directory. After tests complete, whether they pass or fail, the post/always block triggers. The junit step reads and parses the XML files, extracting test counts for passed, failed, and skipped tests. Jenkins displays these results in the UI with trends over time. If any tests fail, the build is marked UNSTABLE. The key insight is that junit only parses reports — it does not run tests — and post/always ensures reports are always published.