From 3 weeks to 30 minutes – a journey through the ups and downs of test
automation
Who am I?
• Peter Thomas– Chief Software Engineer– Operations IT, UBS Investment Bank
• Developer (mostly)• I do some architecture• I have done Testing• I talk a lot (Mentor/Coach)
• From the dark side (consulting) but getting better
Where did we start?
• Existing mainframe legacy application• 3 week manual PPT testing cycle• 12 week delivery cycle
What did we want to do?
• Belief there was a better way to deliver software
• Incremental development to deliver business value quickly
• Address the rapidly changing business landscape with flexibility in delivery
• Build quality into the solutions• Deliver the software rapidly, but in a cost
effective manner• Put the fun back into software delivery
New York London Kiev Hyderabad Hong Kong
2M trades per day 100 billions settling per day in all major currencies50+ exchanges across EMEA and APAC15 scrum teams/120 people9 applicationsProduction releases every 2 weeks
New York London Kiev Hyderabad Hong Kong
200 commits per day1000 artefacts updated per day1 commit every 5 minutes peak
New York London Kiev Hyderabad Hong Kong
24 Build Targets60+ Test Targets800 Automated Functional Tests10, 000 Unit/Integration Tests7, 000 Behavioural Tests
But……..
Our tests were…..
ComplicatedObscure
Random failuresSlow to run
Difficult to fix
“The TDD rut”
ComplicatedObscure
Random failuresSlow to run
Difficult to fix
Test the Right Thing and
Test the Thing Right
When all you have is a hammer, everything looks like
a nail
Why do you test?
Why do you test?
• Because TDD tells me so?• Because (insert favourite method
here) says I should?• So I meet the 80% coverage metric?
Why do you test?
• To accept the solution• To understand and document the solution• To prove its not broken• To find the unknown unknowns• To help us design and build new features• To help us explore what is really needed• To show it won’t crash under load, to
show it is secure (to test the ‘ilities)…?
Why do you test?
Agile testing Quadrants – Lisa Crispin, Janet Gregory
Testing Purposefully
The Right Thing At The Right Level
UnitComponent
System
The Right Thing At The Right Level
UnitComponent
System
•Tests a single class with no dependencies•If dependencies like Spring Context, Database used then called Unit Integration•Tests technical correctness and robustness•Very specific, a failing test indicates an issue in a specific class•Difficult to perform on poor quality code•Very fast to run, should run on the developer’s desktop in the IDE
The Right Thing At The Right Level
UnitComponent
System
•Tests a group of components which are integrated to perform a business relevant function•Can test technical or business correctness, but should be expressed in Domain concepts•Specific, a failing test indicates problems in that component•Easier to perform on poor quality code, provided component boundaries are clear•Can be quick to run, doesn’t need the full application, should run on developers desktop
The Right Thing At The Right Level
UnitComponent
System
•Tests a system at its boundaries as a ‘black box’•Primarily testing for business correctness•Not Specific, a failing test could be caused anywhere in the system flow•Easy to perform on legacy applications, requires little code modification•Slow to run, can be fragile, may not run on developers desktop
What We Wanted
What We Had
Unit tests which weren’t really Unit TestsEnd to End tests when unit tests would have been sufficientDuplicate and redundant End to End tests
The TDD Cycle
TDD?@Test public void shouldBeEmtpyAfterCreation() { ReportObject aTrm = new
ReportObject(); assertNull(aTrm.getEligibleTrm()); assertNull(aTrm.getProcessedEvent());
assertNull(aTrm.getPayloadXml()); }
@Test public void shouldCorrectlySetAttributesViaConstructor() { ReportObject aTrm = new ReportObject(eligibleObject, REPORTABLE_XML); assertEquals(eligibleObject, reportableTrm.getEligibleTrm()); assertEquals(REPORTABLE_XML, reportableTrm.getPayloadXml()); }
@Test public void shouldCorrectlySetFieldsViaSetters() { ReportObject aTrm = new ReportObject(); aTrm.setEligibleTrm(eligibleObject); aTrm.setProcessedEvent(child); aTrm.setPayloadXml(REPORTABLE_XML);
assertEquals(eligibleObject, aTrm.getEligibleTrm()); assertEquals(child, aTrm.getProcessedEvent()); assertEquals(REPORTABLE_XML, aTrm.getPayloadXml()); }
The Hollow Egg
The Hollow Egg98 Tests2.5K LOC
30 Tests200 LOC
RSpec model
Outside In - The TDD Spiral
Make the Intent Clear
How to achieve acceptance without showing your IDE or
log file to the users
Unit Test Naming?
testProcessError()
whenWorkItemIsManuallyAssignedThenClientRuleShouldBeSetToManualOverride()
shouldAllowAnActioningWorkItemToBeUpdated()
Test Data Nightmare
What Do You Demo?
What Do You Demo?
Executable Specification
Improve Testing Stability
Avoiding the Broken Windows syndrome
Separate Progress & Regression Tests
Speed-up Through Parallelism
Identify Unstable Tests
Quarantine Unstable Tests
Avoid External Dependencies
Introduce Fakes
Avoid Time-Dependent Tests
Test Isolation
Asynchronous Testing Headache
Don’t!
• Does your test need to be asynchronous?
• 80/20 rule?• Create synchronous test runner
harness
Asynchronous Testing using Events
So…?
Treat your Tests Like you Treat your Code
“it’s just a test class” is not an excuse
Clean Code applies to tests too
Think about Why You are Testing
Specification tests for internal quality
Business tests for external quality
Think about Who You are Testing For
More people are interested in your tests than you may think
Zero Tolerance to Instability
“It runs OK on my machine” is not a valid response