In agile development, product quality hinges heavily on testing, iterating, improving, and refining based on customer feedback to meet changing demands. To do this effectively, Scrum teams must understand different approaches to testing and how to best apply them. Here is one key concept used to categorize testing – levels of testing – and the variety of popular testing methods these encompass.
Levels of Testing
Testing in software development is carried out at various stages through the project lifecycle, each with a specific purpose. Here are four distinct levels:
- Unit Testing
- Integration Testing
- System Testing
- Acceptance Testing
1. Unit Testing:
This primary level of testing focuses on the smallest testable component of an application – individual methods or functions. Here, each unit of the software is separately examined to ensure it works as expected. The unit testing encourages developers to modularize the code, enhancing its maintainability.
Example Method: White-box Testing
In white-box testing, a tester examines the internal logic and underlying structure of the code. Each flow of the unit (method or function) is typically tested at least once. For example, in Python, the unittest module can be used:
import unittest
def addNumbers(a, b):
return a+b
class TestAddNumbers(unittest.TestCase):
def test_add(self):
self.assertEqual(addNumbers(2,3),5)
unittest.main()
2. Integration Testing:
Integration testing focuses on verifying interaction between different units of the software. This method enables the identification of any issues that could be missed during unit testing.
Example Method: Black-box Testing
Black-box testing validates functional requirements without gaining insights into the internal structure of the system. This testing technique views the system as a “black box,” focusing on input and output.
3. System Testing:
System testing is a process of investigating the entire system. It is carried out after integration testing and is basically aimed at verifying the system meet the specified requirements.
Example Method: Regression Testing
Often used at this level, regression testing ensures that modifications (code refactoring, bug fixes, etc.) haven’t introduced new faults into existing functioning features. The whole system is tested to make sure it still works as expected.
4. Acceptance Testing:
This is the final level of testing where actual users test the system to check whether the system meets the necessary requirements and determine whether it should be accepted or rejected.
Example Method: User Acceptance Testing
User Acceptance Testing (UAT) is carried out by the client and end users. The objective of UAT is to assess if the system can support day-to-day business and user scenarios and ensure it is sufficient for business usage.
Below is a summarized table for quick understanding:
| Level of Testing | Testing Method |
|---|---|
| Unit Testing | White-box Testing |
| Integration Testing | Black-box Testing |
| System Testing | Regression Testing |
| Acceptance Testing | User Acceptance Testing |
Understanding these levels of testing and the methods applied at each one is crucial in agile environments, such as those made possible by Scrum. Proper testing enables teams to quickly identify and fix issues, constantly improve the product, and ultimately deliver a high-quality end product that meets customer expectations.
Practice Test
True/False: In software testing, ‘Black Box Testing’ revolves around examining code’s functionality without any knowledge about internal structure.
- True
- False
Answer: True
Explanation: Black Box Testing focuses on the testing of functionalities and not the internal coding structure. It mainly checks if the system is behaving as expected when providing certain inputs.
Multiple select: Which of the following are types of testing in software development?
- a) Black Box Testing
- b) Grey Box Testing
- c) White Box Testing
- d) Blue Box Testing
Answer: a) Black Box Testing, b) Grey Box Testing, c) White Box Testing
Explanation: Black Box, Grey Box, and White Box testing are common types of software testing. Blue Box Testing does not exist.
Single select: Which method of testing examines functionality without consideration to internal structure?
- a) Black Box Testing
- b) Grey Box Testing
- c) White Box Testing
Answer: a) Black Box Testing
Explanation: Black Box Testing focuses on the examination of functionality without considering the internal structure of the code.
True/False: Grey Box Testing is done without any knowledge of the internal workings of the code.
- True
- False
Answer: False
Explanation: Grey Box Testing is a combination of both Black Box and White Box testing. Testers have partial knowledge of the internal workings of the system.
Multiple select: In the context of Agile testing methodologies, what does ‘Risk-Based Testing’ involve?
- a) Ignoring minor defects
- b) Focusing on areas with the highest risk of failure
- c) Testing random functionalities
- d) Ensuring 100% test coverage
Answer: a) Ignoring minor defects, b) Focusing on areas with the highest risk of failure
Explanation: The main idea behind Risk-Based Testing is to focus on the most critical functionalities or those with the highest risk of failure. Minor defects are often deprioritized.
Single select: Which category of testing involves analyzing the internal structure of a system?
- a) Black Box Testing
- b) Grey Box Testing
- c) White Box Testing
Answer: c) White Box Testing
Explanation: White Box Testing (or glass box, clear box, or structural testing) involves analyzing and examining the internal code structure of a system. It requires knowledge of the code.
True/False: Test-Driven Development (TDD) is a software testing approach in which tests are designed after the code is written.
- True
- False
Answer: False
Explanation: In TDD, tests are written before the code development begins. This process ensures that all parts of the software are tested properly.
Multiple select: Which techniques are part of White Box Testing?
- a) Statement coverage
- b) Branch coverage
- c) Boundary Value Analysis
- d) Decision table testing
Answer: a) Statement coverage, b) Branch coverage
Explanation: Statement coverage and branch coverage are techniques used in White Box Testing because they require knowledge and analysis of the internal code structure.
Single select: Which method of testing is a combination of Black Box and White Box testing?
- a) Red Box Testing
- b) Grey Box Testing
- c) Yellow Box Testing
Answer: b) Grey Box Testing
Explanation: Grey Box Testing combines techniques from both Black Box and White Box testing. Testers have limited knowledge of the internal workings.
True/False: Automated Testing involves manually executing test cases.
- True
- False
Answer: False
Explanation: Automated Testing, as the term suggests, involves using software tools to execute test cases. This is different from Manual Testing, where testers run tests manually.
Multiple select: Which are typical methodologies in Agile testing?
- a) Exploratory Testing
- b) Test-Driven Development
- c) Acceptance Test-Driven Development
- d) User Interface Testing
Answer: a) Exploratory Testing, b) Test-Driven Development, c) Acceptance Test-Driven Development
Explanation: All three are commonly used methodologies in Agile Testing. User Interface Testing, while important in software quality assurance, does not strictly fall under Agile methodologies.
Single select: In which testing methodology does the developer write tests that fail before coding?
- a) Exploratory Testing
- b) Test-Driven Development
- c) Acceptance Test-Driven Development
Answer: b) Test-Driven Development
Explanation: In the Test-Driven Development (TDD) approach, developers write tests that initially fail, then code is written to pass these tests.
True/False: In Acceptance Test-Driven Development (ATDD), developers begin by understanding the requirements and criteria for acceptance.
- True
- False
Answer: True
Explanation: In ATDD, the development team begins by understanding the requirements and acceptance criteria. They then formulate acceptance tests before writing the code.
Multiple Select: Which of the following testing categories are well suited for automation?
- a) Unit Testing
- b) Functional Testing
- c) Integration Testing
- d) Exploratory Testing
Answer: a) Unit Testing, b) Functional Testing, c) Integration Testing
Explanation: Unit, functional, and integration tests are commonly automated, especially in a continuous integration and delivery workflow. Exploratory testing, on the other hand, relies on the tester’s creativity and intuition.
Single Select: Which Agile testing technique involves stakeholders and users during the requirement clarification phase?
- a) Exploratory Testing
- b) Test-Driven Development
- c) Acceptance Test-Driven Development
Answer: c) Acceptance Test-Driven Development
Explanation: In Acceptance Test-Driven Development, stakeholders and users are involved from the early stages of requirement clarification to ensure the development meets user requirements and expectations.
Interview Questions
Can you describe the concept of categorizing testing methods in Agile development?
In Agile development, testing methods can be categorized based on the scope, the time of execution and the level of formality. Some of the categories include unit testing, functional testing, integration testing, system testing, regression testing, and acceptance testing.
What is unit testing and which category does it fall under?
Unit testing falls under the category of scope. It’s a method used to test individual units of source code to determine whether they are fit for use. Unit testing is done by developers and it is automated.
Describe functional testing and its category.
Functional testing falls under the objective category. It is a type of testing done to ensure that the functionality of an application or system is working as expected. It verifies each function of the software by providing appropriate input to check the output.
What is regression testing and in which category can we find it?
Regression testing is found under the timing category. Regression testing is a type of software testing which is done to make sure that the previously developed and tested software still performs after a change.
What is acceptance testing and which category does it belong to in the test methodology?
Acceptance testing belongs to the level of formality category. It’s a type of testing that is done to verify if a product is developed as per the specified requirements and satisfies the client’s needs.
Can you describe the category of system testing?
System testing falls under the scope category in testing. It’s a type of testing that tests the system as a whole including its software and hardware components integrated together and to ensure it works as expected.
What is integration testing and which category does it fall into?
Integration testing comes under the scope category. It’s a level of testing where individual units are combined and tested as a group. The aim of this testing is to expose faults in the interaction between integrated units.
What’s the nature of automated testing and to what category does it belong?
Automated testing is part of the means category where the execution of the tests is done through an automation tool. This method is applied to re-run the test scenarios that were performed manually, quickly, and repeatedly.
Can you define sanity testing and specify its category?
Sanity testing falls under the timing category. It’s a kind of software testing performed after receiving a software build with minor changes in code or functionality to ascertain that the bugs have been fixed and no further issues are introduced due to these changes.
Please define the category of alpha and beta testing.
Alpha and beta testing fall under the level of formality category. Alpha testing is done internally by the team while beta testing is done externally by a select group of end users before the software is released to the public.
What does the level of formality category in testing entail?
The level of formality category refers to how formal or rigid the testing process is. It can go from exploratory testing, which is less formal, up to acceptance testing which typically has a high level of formality.
Define load testing and the category it belongs to.
Load testing belongs to the objective category. It’s a type of non-functional testing which determines a system’s performance under real-life load conditions. It helps to identify the maximum capacity of an application and its scalability.
What is security testing and which category does it fall under?
Security testing falls under the objective category. It helps to identify vulnerabilities, threats, risks in a software application and prevent malicious attacks from intruders.
What type of testing falls under the timing category?
Types of testing that fall under the timing category include regression testing, sanity testing, and smoke testing. These tests are usually conducted at specific times during the software development and deployment process.
What is stress testing and what category does it belong to in test methodology?
Stress testing belongs to the objective category in test methodology. It’s a type of testing that determines the robustness of software by testing beyond the limits of normal operation.
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