Unit Testing From The Trenches

Alexandru BolboacaAlexandru BolboacaV1.0, because I embrace changeV1.0, because I embrace change

I write tests because I don't want this to happen

...and I don't want to be this guy

Agenda

Some clarifications

5 practical ideas

Answers to your questions

Clarification #1: What is a unit test?

A piece of code that checks a unit from the system under test (SUT)

A unit = a class (basic)A unit = a behavior (advanced)

A unit test

AssertAssertActAct

ArrangeArrange GivenGivenWhenWhenThenThen

Clarification #2: Types of tests

Clarification #3: When we write tests

Design, Code, Test = Test After

Design, Test, Code = Test First Programming

Test, Code, Design = Test Driven Development

Clarification #4: Who writes the tests

Technology-facing tests: Devs

Business facing tests: Analysts and Devs

Critique tests: Testers and Devs

Clarification #5: Good unit tests

SimpleFast

ReadableIndependentRepeatableEasy to run

Clarification #6: Write tests for any tech

… … including bash scriptingincluding bash scripting

Anything else to clarify?

5 Practical Ideas

Situation #1

Cost: 12 hrs of businessCost: 12 hrs of businessCause: “a time calculation that was Cause: “a time calculation that was

incorrect for the leap year”incorrect for the leap year”

Practical Idea #1

The The immune systemimmune system of your product of your product

Situation #2

Large proportion of tests that are:

SlowUnpredictable

Practical Idea #2

Situation #3

I measure the development timeI measure the development timeI want the unit test coverage to be 90%I want the unit test coverage to be 90%

Practical Idea #3

Managers measure Running Tested Features

Developers measure coverage

Guideline: Coverage must increase

Situation #4

We have unit tests, BUT:

We extensively use the debugger

Unit tests are based on test plans

Testers still execute repeatedly manual test plans

Practical Idea #4Use automated developer tests to:

Executable Specifications

Replace debugging

Complement learning

Replace repetitive manual testing

Situation #5

Practical Idea #5

Wrap up

I measure RTF/sprintI measure RTF/sprint

Alexandru Bolboaca

alex.bolboaca@mozaicworks.com

@alexboly, alexbolboaca.ro

● Trainings: Unit Testing, TDD, Legacy Code

● Technical Mentoring, Coaching, on-site and remote

Questions

The important thing is not to stop questioningThe important thing is not to stop questioning