Testing shared libraries in Jenkins - Step-by-Step Execution

Process Flow - Testing shared libraries

Write shared library code

↓

Write unit tests for library

↓

Configure Jenkins pipeline to load library

↓

Run tests in pipeline

↓

Check test results

↓

Fix issues or confirm success

This flow shows writing shared library code, adding tests, running them in Jenkins, and checking results.

Execution Sample

Jenkins

def add(a, b) {
  return a + b
}

// Test
assert add(2, 3) == 5

A simple shared library function add and a test assertion checking its output.

Process Table

Step	Action	Evaluation	Result
1	Call add(2, 3)	2 + 3	5
2	Assert add(2, 3) == 5	5 == 5	True - Test passes
3	Run pipeline stage 'Test'	Tests executed	All tests passed
4	Check test report	No failures	Success
5	Pipeline ends	Tests passed	Library verified

💡 All tests passed, pipeline completes successfully

Status Tracker

Variable	Start	After Step 1	After Step 2	Final
a	undefined	2	2	2
b	undefined	3	3	3
result	undefined	5	5	5
test_passed	false	false	true	true

Key Moments - 2 Insights

Why does the test fail if the assertion is incorrect?

Because in step 2 of the execution_table, the assertion evaluates to false, causing the pipeline to mark the test as failed and stop or report errors.

How does Jenkins know to load the shared library for testing?

Jenkins pipeline configuration includes a 'library' step that loads the shared library before running tests, as implied in step 3.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result of add(2, 3) at step 1?

A 5

B 23

C Error

D Undefined

💡 Hint

Check the 'Result' column in row for Step 1 in execution_table

At which step does the test assertion confirm success?

A Step 4

B Step 1

C Step 2

D Step 5

💡 Hint

Look at the 'Action' and 'Result' columns in execution_table for assertion evaluation

If the assertion failed, how would the pipeline result change in the table?

A Step 3 would show 'Tests executed' with all passed

B Step 4 would show 'Failures detected'

C Step 5 would show 'Library verified'

D No change in any step

💡 Hint

Refer to the 'Check test report' step in execution_table and what happens on test failures

Concept Snapshot

Testing shared libraries in Jenkins:
- Write library code and unit tests
- Configure Jenkins pipeline to load the library
- Run tests inside pipeline stages
- Check test results for pass/fail
- Fix code if tests fail, else confirm success

Full Transcript

Testing shared libraries involves writing reusable code and unit tests for it. Jenkins pipelines load the shared library and run these tests automatically. Each step calls functions, evaluates assertions, and reports results. If tests pass, the pipeline completes successfully confirming the library works. If tests fail, Jenkins reports errors so you can fix the code. This visual trace shows calling a simple add function, asserting its output, running tests in Jenkins, and checking the final success status.