Different Testing methods
Unit vs Integration vs System vs E2E Testing
The table below illustrates the most critical characteristics and differences among Unit, Integration, System, and End-to-End Testing, and when to apply each methodology in a project.
Scope
Modules, APIs
Modules, interfaces
Application, system
All sub-systems, network dependencies, services and databases
Size
Tiny
Small to medium
Large
X-Large
Environment
Development
Integration test
QA test
Production like
Data
Mock data
Test data
Test data
Copy of real production data
System Under Test
Isolated unit test
Interfaces and flow data between the modules
Particular system as a whole
Application flow from start to end
Scenarios
Developer perspectives
Developers and IT Pro tester perspectives
Developer and QA tester perspectives
End-user perspectives
When
After each build
After Unit testing
Before E2E testing and after Unit and Integration testing
After System testing
Automated or Manual
Automated
Manual or automated
Manual or automated
Manual
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