Notes

All about Testing

• The general idea across all testing frameworks is to allow developers to write code that would specify the behavior of a function or module or class.

• Tesing one function at a time is vulnerable to false negatives and false positives.

• Why do we test?

  • To make sure everything works.
  • Increase flexibility & reduce fear of code.
• Automated Tests are known as Specs, they:
  • Make collaboration easier.
  • Produce Documentation.

How We Test

• Testing Framework : Runs the tests and presents them to a user.

• Assertion Libraries : Backbone of written tests, the code that we use to write our tests.

• Mocha : JS testing framwork which is highly flexible; supports a variety of assertion libraries.

• Domain Specific Language : Refers to a computer language specialized for a particular purpose

What do we Test?

• The public interface:
  • Ask yourself, “What is the public interface of the module or class I’m writing?”
  • When in doubt, make sure that you at least have the most important and/or complex parts of that interface working as intended.

The Testing Pyramid

• Unit Tests : The smallest unit of testing.

  • Used to test smallest pieces in isolation before putting everything together.
  • Tests ONE THING.

• Integration Tests : Test the interactions between two pieces of your application.

• End to End : Closest automated tests come to testing the actual user experience of your application.

Reading Tests

• Most important thing about a test is that it is readable and understandable

describe("avgValue()", function () {
  it("should return the average of an array of numbers", function () {
    assert.equal(avgValue([10, 20]), 15);
  });
});

• avgValue() => The function we will be testing.
• it(“string”) => describes the desired output.

Test-Driven Development

• TDD is a quick repetitive cycle that revolves around first determining what a piece of code should do and writing tests for that behavior before actually writing any code.

Motivations for TDD