Levels of Testing

Test Levels are the group of test activities that are organised and managed together. For every test level suitable test environment is required.

Test levels are characterized by the following attributes: 

•  Specific objectives
•  Test basis, referenced to derive test cases 
• Test object (i.e., what is being tested)
• Typical defects and failures
•  Specific approaches and responsibilities 

1. Component Testing- 

Component testing (also known as unit or module testing) focuses on components that are separately testable.

 Objectives of component testing include: 

• Reducing risk 
• Verifying whether the functional and non-functional behaviors of the component are as designed and specified 
• Building confidence in the component’s quality 
• Finding defects in the component 
• Preventing defects from escaping to higher test levels.

Component testing is often done in isolation from the rest of the system, depending on the software development life cycle model and the system, which may require mock objects, service virtualization, harnesses, stubs, and drivers. Component testing may cover functionality (e.g., correctness of calculations), non-functional characteristics (e.g., searching for memory leaks), and structural properties (e.g., decision testing). 

2. Integration Testing -

Integration testing focuses on interactions between components or systems. 

Objectives of integration testing include: 

• Reducing risk 
• Verifying whether the functional and non-functional behaviors of the interfaces are as designed and specified
• Building confidence in the quality of the interfaces
• Finding defects (which may be in the interfaces themselves or within the components or systems)
• Preventing defects from escaping to higher test levels 

Component integration testing is often the responsibility of developers. 

System integration testing is generally the responsibility of testers.

3. System Testing-

System testing focuses on the behavior and capabilities of a whole system or product, often considering the end-to-end tasks the system can perform and the non-functional behaviors it exhibits while performing those tasks. 

Objectives of system testing include:

• Reducing risk 
• Verifying whether the functional and non-functional behaviors of the system are as designed and specified
• Validating that the system is complete and will work as expected 
• Building confidence in the quality of the system as a whole 
• Finding defects
• Preventing defects from escaping to higher test levels or production 

4. Acceptance testing 

Acceptance testing, like system testing, typically focuses on the behavior and capabilities of a whole system or product. 

Objectives of acceptance testing include: 

• Establishing confidence in the quality of the system as a whole 
• Validating that the system is complete and will work as expected 
• Verifying that functional and non-functional behaviors of the system are as specified 

Common forms of acceptance testing include the following: 

• User acceptance testing
• Operational acceptance testing
• Contractual and regulatory acceptance testing
• Alpha and beta testing.

Here are the test basis related to each level-

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Here are the Object for each level-

Here are the defects we focus on each level-