Test result trends in Jenkins - Mini Project: Build & Apply

Test Result Trends in Jenkins

📖 Scenario: You are a Jenkins administrator who wants to track how test results change over time for a software project. This helps the team see if tests are improving or failing more often.

🎯 Goal: Build a simple Jenkins pipeline script that collects test results from multiple builds and prints a trend summary showing how many tests passed and failed in each build.

📋 What You'll Learn

Create a list variable called builds with test result data for 3 builds

Add a variable called threshold to mark the minimum passing tests

Use a for loop to analyze each build's test results and create a summary list

Print the summary list showing test pass/fail trends

💡 Why This Matters

🌍 Real World

Tracking test result trends helps teams quickly spot if recent changes break tests or improve quality.

💼 Career

Jenkins administrators and DevOps engineers often create scripts to analyze build data and report test health.

1

Create test result data

Create a list variable called builds with 3 dictionaries. Each dictionary should have keys build_number, passed, and failed with these exact values: build 1: passed 50, failed 5; build 2: passed 48, failed 7; build 3: passed 52, failed 3.

Jenkins

# Create the list variable builds with 3 dictionaries for test results
# Your code here

Hint

Think of builds as a list of snapshots showing test results for each build.

2

Add a passing threshold

Add a variable called threshold and set it to 50. This will be the minimum number of passed tests to consider a build successful.

Jenkins

builds = [
    {'build_number': 1, 'passed': 50, 'failed': 5},
    {'build_number': 2, 'passed': 48, 'failed': 7},
    {'build_number': 3, 'passed': 52, 'failed': 3}
]
# Add the threshold variable below
# Your code here

Hint

This threshold helps decide if a build's test results are good enough.

3

Analyze test results with a loop

Use a for loop with variables build to go through each item in builds. Inside the loop, create a string status that is 'PASS' if build['passed'] is greater than or equal to threshold, otherwise 'FAIL'. Append a dictionary with keys build_number and status to a list called summary. Initialize summary as an empty list before the loop.

Jenkins

builds = [
    {'build_number': 1, 'passed': 50, 'failed': 5},
    {'build_number': 2, 'passed': 48, 'failed': 7},
    {'build_number': 3, 'passed': 52, 'failed': 3}
]
threshold = 50

# Initialize summary list
# Use a for loop to analyze each build and add status
# Your code here

Hint

Use a simple if-else inside the loop to decide the status for each build.

4

Print the test result trend summary

Write a print statement to display the summary list.

Jenkins

builds = [
    {'build_number': 1, 'passed': 50, 'failed': 5},
    {'build_number': 2, 'passed': 48, 'failed': 7},
    {'build_number': 3, 'passed': 52, 'failed': 3}
]
threshold = 50

summary = []
for build in builds:
    status = 'PASS' if build['passed'] >= threshold else 'FAIL'
    summary.append({'build_number': build['build_number'], 'status': status})

# Print the summary list below
# Your code here

Hint

Just print the summary list to see the trend.

Practice

1. What is the main purpose of test result trends in Jenkins?

easy

A. To show how test results change over time

B. To run tests faster

C. To deploy applications automatically

D. To create new test cases

Solution

1. Step 1: Understand test result trends concept

   Test result trends track test outcomes across multiple builds to see progress or issues.

2. Step 2: Identify the main purpose

   The main goal is to observe changes in test results over time, helping catch problems early.

3. Final Answer:

   To show how test results change over time -> Option A

4. Quick Check:

   Test result trends = show changes over time [OK]

Hint: Trends track test results over builds, not speed or deployment [OK]

Common Mistakes:

• Confusing trends with deployment automation
• Thinking trends create tests
• Assuming trends speed up tests

2. Which Jenkins plugin is required to publish test result trends from JUnit XML reports?

easy

A. Git plugin

B. Docker plugin

C. Pipeline plugin

D. JUnit plugin

Solution

1. Step 1: Identify plugin for JUnit XML reports

   JUnit plugin in Jenkins processes JUnit XML test reports and generates test result trends.

2. Step 2: Confirm plugin role

   Only the JUnit plugin handles test result publishing and trend visualization from JUnit reports.

3. Final Answer:

   JUnit plugin -> Option D

4. Quick Check:

   JUnit plugin publishes test trends [OK]

Hint: JUnit plugin handles JUnit XML test reports and trends [OK]

Common Mistakes:

• Choosing Git plugin which manages source code
• Selecting Docker plugin unrelated to tests
• Confusing Pipeline plugin with test reporting

3. Given this Jenkins pipeline snippet, what will happen if the junit '**/test-results.xml' step is missing?

pipeline {
  agent any
  stages {
    stage('Test') {
      steps {
        sh 'run-tests.sh'
        junit '**/test-results.xml'
      }
    }
  }
}

medium

A. Test results will be published and trends shown

B. No test results will be published, no trends available

C. Pipeline will fail with syntax error

D. Tests will not run at all

Solution

1. Step 1: Understand the role of junit step

   The junit step publishes test results from XML files and enables trend graphs.

2. Step 2: Analyze missing junit step effect

   Without junit, test results are not published, so no trends appear, but tests still run.

3. Final Answer:

   No test results will be published, no trends available -> Option B

4. Quick Check:

   Missing junit step = no published results [OK]

Hint: Without junit step, no test results or trends appear [OK]

Common Mistakes:

• Thinking pipeline fails without junit step
• Assuming tests won't run without junit
• Believing trends show without publishing results

4. You added the junit '**/results.xml' step but Jenkins shows no test trends. What is the most likely cause?

medium

A. The XML file path pattern is incorrect or no files match

B. The Jenkins server is offline

C. The pipeline syntax is invalid

D. The tests did not run

Solution

1. Step 1: Check file path pattern for test reports

   If the pattern **/results.xml does not match any files, no results are published.

2. Step 2: Confirm Jenkins behavior on missing files

   Jenkins silently skips publishing if no matching files found, so no trends appear.

3. Final Answer:

   The XML file path pattern is incorrect or no files match -> Option A

4. Quick Check:

   Wrong file path = no test trends [OK]

Hint: Verify XML file path matches actual test report location [OK]

Common Mistakes:

• Assuming Jenkins is offline without checking
• Blaming pipeline syntax without error
• Thinking tests must fail to hide trends

5. You want to track test result trends for multiple test suites in Jenkins, each producing separate JUnit XML files in different folders. How should you configure the junit step to show combined trends?

hard

A. Manually merge XML files before publishing

B. Use multiple junit steps, one per folder

C. Use a single junit step with a combined glob pattern like '**/test-results/*.xml'

D. Publish only one folder's results to avoid confusion

Solution

1. Step 1: Understand how junit step handles multiple files

   The junit step accepts glob patterns to include multiple XML files from different folders.

2. Step 2: Choose best practice for combined trends

   Using a single junit step with a combined pattern like '**/test-results/*.xml' publishes all results together, enabling combined trends.

3. Final Answer:

   Use a single junit step with a combined glob pattern like '**/test-results/*.xml' -> Option C

4. Quick Check:

   Single junit step + combined pattern = combined trends [OK]

Hint: Use one junit step with glob pattern to include all XML files [OK]

Common Mistakes:

• Using multiple junit steps causing separate trends
• Trying to merge XML files manually
• Ignoring some test suites results