Continuous Integration

Question 1

What is Continuous Integration (CI)?

Benefit?

Answer 1

• The practice of quickly integrating newly developed code with the rest of the application code.
• The process is usually automated to produce a build artifact at the end of the process.
• This saves time when the application is ready to be released.

Question 2

What are the four releases in Traditional Product Delivery?

Answer 2

1. Alpha release
2. Beta release
3. Release candidate
4. Release

Question 3

What are the three environments in Modern Feature Delivery?

Answer 3

1. Development environment
2. Staging environment
3. Production environment

Question 4

What is the Development Environment?

Answer 4

It is where the work of a single development team is put together and updated throughout a two-week sprint.

Question 5

What is the Staging Environment?

Answer 5

• Where the work of multiple development teams is put together
• Updated at the end of every two week sprint

It looks like the production environment

Question 6

What is the Production Environment?

Answer 6

• Where the work of multiple development teams becomes available to customers
• It is updated when the business considers the time is right.

Question 7

What is Shift Left Testing?

Answer 7

A software testing technique that involves performing tests earlier in the development process

Question 8

What is the Test Pyramid?

Answer 8

The test pyramid describes the types of tests carried out in development:
1. Unit Tests
2. Service Tests
3. End-to-End Tests.

Question 9

What are Unit Tests in the Test Pyramid?

Answer 9

• Tests run in the development environment to ensure functions work correctly
• There may be thousands of unit tests run in seconds

Question 10

What are Service Tests in the Test Pyramid?

Answer 10

• Run in the staging environment to ensure services are working correctly
• Sometimes hundreds of service tests run in minutes

Question 11

What are End-to-End Tests in the Test Pyramid?

Answer 11

• Run in the staging environment to ensure that the application works properly
• Tens of end-to-end tests run in several minutes by mimicking human interaction

Question 12

What is the Test Snow Cone? Is it a good idea?

Answer 12

• An antipattern where there are many more end-to-end tests than service tests than unit tests.
• This is a bad idea because if a test fails, you have to continually delve deeper to diagnose the issue

Question 13

What are Brittle Tests?

Answer 13

A brittle test is one that fails because another service fails.

Question 14

What are Flaky Tests?

(Why?)

Answer 14

A flaky test is one that sometimes fails because another service fails — perhaps due to a time-out or race condition.

Question 15

What is the Normalisation of Deviance? What does it imply for testing?

Answer 15

• The idea that over time, we become so accustomed to things being wrong that we start to accept them as being normal and not a problem
• We should find and eliminate flaky tests (“it always fails like that” is unacceptable)

Question 16

What are Build Light Indicators?

Pro and Con?

Answer 16

• A visual indicator to inform a developers about the current status of the project.
• Pro: Benefits accountability as everyone is aware if a build goes red
• Con adds pressure on developers, potentially preventing them from commiting changes

Question 17

What is Integration Hell?

Answer 17

An anti-pattern of software development that brings together the pieces of a software system (far too) late.

Question 18

What is the point of Rule 1: run commit tests locally?

Answer 18

The deployment pipeline is a valuable shared resource that one should avoid blocking with unnecessary test failures

Question 19

What is the point of Rule 2: wait for the results?

Answer 19

It allows those who make changes to be present and ready to fix any problems immediately.

Question 20

What is the point of Rule 3: fix or revert failures within 10 minutes?

Answer 20

To avoid blocking useful progress by others.

Question 21

What is the point of Rule 4: if a teammate breaks the rules, revert their changes?

Answer 21

To avoid others blocking useful progress.

Question 22

What is the point of Rule 5: if someone else notices you caused a failure before you notice it’s a build sin?

Answer 22

It encourages developers to pay more attention to their changes and its impact on the build.

Question 23

What is the point of Rule 6: once a commit passes move on to your next task

Answer 23

Rapid, automated testing frees up time to do new, useful work.

Question 24

What is the point of Rule 7: if any test fails it is the responsibility of the committer?

Answer 24

Someone takes responsibility for a failure and its fix.

Question 25

What is the point of Rule 8: it is the responsibility of everyone who may be responsible to agree who will fix a failure?

Answer 25

This ensures that someone (or many people) takes responsibility for fixing failures

Question 26

What is the point of Rule 9: monitor the progress of your change?

Answer 26

It ensures that software can be rejected as soon as it is shown not to be in a releasable state.

Question 27

What is the point of Rule 10: address any pipeline failure immediately?

Answer 27

It ensures the pipeline stays clear for other changes and avoids delays in progress

Question 28

What are Farley's 10 rules for continuous integration?

Answer 28

1. Run commit tests locally 2. Wait for results 3. Fix or revert failures within 10 minutes 4. If a teammate breaks the rules, revert their changes 5. If someone else notices you caused a build failure, before you do, its a build sin 6. Once commit passes, move on to your next task 7. If any test fails, it's the responsibility of the committer 8. It is the responsibility of everyone who may be responsible to agree who will fix a failure 9. Monitor the progress of your change 10. Address any pipeline failure immediately