Unit testing

Question 1

What is a unit of work?

Answer 1

All the actions that take place between the invocation of an entry point up until a noticeable end result through one or more exit points. The entry point is the thing we trigger.

Question 2

How many exit and entry points could a unit of work have?

Answer 2

one or more exit points, one entry points

Question 3

Is the entry point something private or public?

Answer 3

Public

Question 4

What is an exit point?

Answer 4

An exit point is an observable consequence of a unit of work that can be verified from outside the system. It’s how the system communicates or changes in a way that clients can observe.

Question 5

What types of exit point exists?

Answer 5

Returned value
Change in state of some part f the system
Callout of third dependency such us logging

Question 6

What are the characteristics of good test?

Answer 6

Easy to understand the intention
Easy to read and write
Automated
Consistent
Useful and actionable results
Run with a “push of a button”
Easy to trace erros

Question 7

What does it mean that a test is consistent?

Answer 7

Each run gets the same result if u did not change anything

Question 8

What are the characteristics of a good unit test?

Answer 8

Run quickly.
Full control of the code under test.
Do not call external dependencies such as network or database calls, runs in memory.
Isolated.
Linear when it makes sense.

Question 9

What is the main difference between unit and integration tests?

Answer 9

Unit tests do not depend in configuring external dependencies such as databases or the filesystem.

Question 10

Mention 3 questions of the art of unit testing checklist to ensure something is a unit test

Answer 10

Can I run and get results from a test I wrote two weeks or months or years ago?
Can any member of my team run and get results from tests I wrote two
months ago?
Can I run all the tests I’ve written in no more than a few minutes?
Can I run all the tests I’ve written at the push of a button?
Can I write a basic test in no more than a few minutes?
Do my tests pass when there are bugs in another team’s code?
Do my tests show the same results when run on different machines or environments?
Do my tests stop working if there’s no database, network, or deployment?
If I delete, move, or change one test, do other tests remain unaffected?

Question 11

What is the consequence of not having isolation of external dependencies in a test?

Answer 11

Too much points of failure.

Question 12

What is a regression?

Answer 12

is broken functionality—code that used to work. You
can also think of it as one or more units of work that once worked and now
don’t.

Question 13

What three main criteria does exist to determine a good test.

Answer 13

Readability
Maintainability
Trust

Question 14

What is a unit test?

Answer 14

A unit test is an automated piece of code that invokes the unit of work through an entry
point and then checks one of its exit points. A unit test is almost always written using a
unit testing framework. It can be written easily and runs quickly. It’s trustworthy,
readable, and maintainable. It is consistent as long as the production code we control has
not changed.

Question 15

What does it mean the USE naming convention?

Answer 15

Unit of work under test
Scenario
Expected behavior

Question 16

What is the assertion roulette?

Answer 16

Assertion roulette is when a single test has multiple assertions without clear indication of which one failed, making it hard to identify the exact reason for test failure.