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Better Requirements Better Testability

The best testing of Software application depends on its Test-ability. It is an attribute associated with the software quality.

Testability may be defined as the degree of “How difficult it is to test the software system”. It is mainly related to the degree to which software artifacts like SRS (software requirement specification), FRD (Functional Design document), software system, etc. support testing for the software application under test.

To understand the term testability better, let’s understand how it works. Test team is provided with software requirements and other supporting documents out of which they carve out the test cases to cover the complete end to end testing. Testability is the measure of how easy it is to write minimum number of test cases that covers the entire testing scope for a software application without missing any possible test scenario that could introduce a fault or error in a software system. The minimum number of test cases in a test suite results in the higher degree of testability. Now, better the requirements given for a software product, it will help test team to understand the application in the best way and hence it will help them to write minimum number of test cases which are unambiguous and complete that will results into higher testability.

Better Requirements Better Testability

Testability vs Effort:

  • Higher Testability: Concrete and unambiguous test cases which are minimum to count in a test suite to cover the complete system end to end testing. This is higher degree of testability with minimum effort required. Higher degree of testability ensures complete end to end application testing without missing any possible defect scenario.
  • Lower Testability: If requirements are not clear or well introduced, which may not be completely digested by the testing team and result in creating the weaker tests that do not cover the complete functional testing of a software application. These weaker tests result into lower degree of testability that may demand more efforts from the test team. Also when there is lower degree of testability there are always chances of skipping defects or bug scenarios in application under test.


Effort and Effectiveness for Testability:

  • Software Requirements: During requirement gathering phase, SRS and FRD documents should be captured with full and complete requirements avoiding ambiguity or incomplete scenarios. Better are the requirements captured, it will result in higher degree of testability. Weak SRS and FRDs results in lower degree of testability and hence result in more testing effort with no guarantee of completion of all possible test scenarios.
  • Software Properties: Degree of testability also depends on the size, complexity and feasibility of the software project. Big size software project should be broken down into numerous modules with each module has its own complete FRD and system integration requirements. This will reduce the project complexity and result in higher degree of testability.
  • Test methods Properties: Testability also depends on the methods used for testing. Requirement should be crystal clear that could assist developers to understand well and do unit test (white box) and testing team can write the required number of test cases to do functional testing (black box). As per need if big application is broken down into number of modules then test cases should also cover the integration testing which will form the complete test suite. Also, as per the demand of non-functional testing like performance, usability, security and compatibility should be covered to achieve higher degree of testability.
  • Testing Process: The Fundamental Test Process comprises five activities as follows. Planning, Specification, Execution, Recording and Checking for Test Completion. Testing starts from planning of test cases from SRS which are specified into test documents. These test document with test cases are executed by test engineer who records the result and compare the output with expected output and completes the test process either reporting the defect or passing the test case when it gets executed successfully. Better requirements helps in better planning and specifications for designing the best test cases for a test suite.
  • Qualification and Motivation of Test team: Just providing the complete SRS document is not sufficient but the test team should comprise of skillful and well qualified test professionals and it is the duty of project management to keep them motivated in order to increase the test efficiency.


Factors determining Software Components Testability:

The Testability of software components is determined by the following factors:

  • Controllable: The degree to which the component state is controllable as per testing need.
  • Responsibilities: The degree to which the component responsibilities are well defined.
  • Understandable: The degree to which the component undergoing testing is self-defining and well documented.
  • Observable: The degree to which end or intermediate test results are observable.
  • Isolated: The degree to which the component is isolated for testing.
  • Automated: The degree to which it is possible to automate test cases of the component undergoing testing.
  • Heterogeneity: The degree to which diverse technologies are used that requires diverse test methods and testing tools to capture end to end software application test results.


Over to you:

Better requirements which are complete in entirety and understandable for a software application results in better Testability which lowers the test team effort and increases the test efficiency.
Sharing your own testing experience, tips or testing secrets in comments below will definitely make this article more interesting and helpful!!
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1 comment to Better Requirements Better Testability

  • Sanjiv

    The point you covered here are awesome. I really liked Testability vs Effort points mentioned here.


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