INTRO TO TESTING
OBJECTIVES
- Discuss why testing is a best practice
- Explain different approaches to testing
- Describe different levels of testing and where they fit on the Pyramid of Testing
- Describe code coverage
why is testing a best practice?
Something that is untested is broken.
- Helps you write cleaner code
- Helps document code
- Helps you get a job
- Helps you sleep at night
why is testing a best practice?
Helps you write cleaner code
why is testing a best practice?
Helps document code
describe("Hello World", function() {
it("should say 'Hello, World!' when ran", function() {
expect(code.helloWorld()).to.equal("Hello, World!");
});
});Does this not tell you exactly what the code is expected to do?
Isn't that kind of what docs do?
why is testing a best practice?
Helps you get a job
why is testing a best practice?
Helps you sleep at night
Something that is untested is broken.
Different testing approaches
Test-Driven Development
"Assert" & "Expect"
Makes sense to engineers
Write test code first. THEN the problem-solving code.
Does the code work?
Different testing approaches
"Should"
behavior-Driven Development
Makes sense to whole team
Does the code do what it's supposed to?
Discuss needed behavior with other stakeholders.
Different testing approaches
"Should"
Test-Driven
Development
behavior-Driven Development
"Assert" & "Expect"
Makes sense to engineers
Makes sense to whole team
Write test code first. THEN the problem-solving code.
Does the code do what it's supposed to??
Discuss needed behavior with other stakeholders.
Does the code work?
Do these things need to be mutually exclusive?
Nope
levels of testing
80%
15%
5%
levels of testing
80%
15%
5%
levels of testing
Unit Tests
Should be fast, isolated, and repeatable
Focuses on small pieces of code, typically functions
A strict, written contract that the piece of code must satisfy
Can be automated or manually run
levels of testing
Integration Tests
Can and will use threads, access the database or do whatever is required to ensure that all of the code and the different environment changes will work correctly.
Focuses on units combined and tested as a group.
Verifies functional, performance, and reliability of features
Can be automated or manually run
levels of testing
UI / functional Tests
Microsoft Typepad has 325 functional requirements.
User testing of functional requirements of program.
Does this application behave in expected ways?
webdriver.js is a great tool for functional testing
Code coverage
How much of the program's code is covered by tests?
"Whenever you are tempted to type something into a print statement or debugger expression, write it as a test instead"
-- Martin Fowler
Code coverage is collected by using a specialized tool to instrument the binaries to add tracing calls and run a full set of automated tests against the instrumented product.
Code coverage
While code coverage is a good metric of how much testing you are doing, it is not necessarily a good metric of how well you are testing your product
DISCLAIMER:
Review
Review
- Helps you write cleaner code
- Helps document code
- Helps you get a job
- Helps you sleep at night
Why test your code?
Review
Red: write the test, run it --> fail
Green: make it pass --> pass
Refactor: make it better
What does red, green, refactor mean?
Review
TDD tests are mostly understood by engineers
BDD tests can be understood by most
What is the biggest difference between TDD and BDD?
Review
Individual functions
What does a unit test test?
Review
Groups of functions, i.e. route handlers
What does an integration test test?
Review
What is the most widely accepted pyramid of testing?
80%
15%
5%
Review
What is code coverage?
How much of your code is tested