# Why?

• preserve intent even when underlying code changes
• prevent regressions during refactoring
• automate application response so you don't have to do it manually

# Terminology

# Assertion

• worker bees of testing
• perform the actual checks

# Test runner

• runs your tests and provides feedback

# Test database

• dummy data for the tests to work with
• fixtures: sample data

# Types of Tests

# Unit Tests

• Test the smallest blocks of code
• Usually individual functions, methods, components, and modules

# Integration

• test how various parts of your application interact
• e.g. test how your app interacts with your database
• does not expect specific values only that different parts of your app can work together
• enzyme
  • mount component
  • simulate a click event
  • make a mock API request

# Functional tests

• tests the business requirements of an application
• checks for correctness of a feature by comparing results of a given input against a specification
• similar to integration tests but the difference is that functional tests expect specific values
• e.g. integration tests check that your app can query a database whereas a functional test would ask for a specific value from the database

# End-to-end / Acceptance tests

• verifies the correctness of user flow
• e.g. making that users can complete an ecommerce transaction
• useful but hard to maintain

# References

https://stackoverflow.com/questions/4904096/whats-the-difference-between-unit-functional-acceptance-and-integration-test https://www.atlassian.com/continuous-delivery/software-testing/types-of-software-testing