Types of Test Coverage
- Statement Coverage: A test suite is said to achieve statement coverage if every statement in the software has been executed at least once during testing. This type of test design coverage ensures that every statement in the software has been executed at least once. This is the most basic form of test design coverage and is often used as a starting point for more comprehensive testing.
- Decision Coverage: A test suite is said to achieve decision coverage if every decision (e.g. if-then-else) in the software has been taken both true and false during testing. This type of test design coverage ensures that every decision (i.e. every ‘if’ or ‘case’) in the software has been executed with all possible outcomes. This is a more comprehensive form of testing than statement coverage and can help to uncover errors that may not be obvious from simply executing every statement.
- Condition Coverage: A test suite is said to achieve condition coverage if every condition in the software has been evaluated as both true and false during testing. This type of test design coverage ensures that all the conditions within a decision have been executed with all possible outcomes. This is a more comprehensive form of testing than decision coverage and can help to uncover errors that may not be obvious from simply executing every decision.
- Multi-Condition Coverage: A test suite is said to achieve multi-condition coverage if all combinations of conditions in the software have been evaluated during testing. This type of test design coverage extends condition coverage by testing all the conditions within a decision with all possible combinations of values. This is a more comprehensive form of testing than condition coverage and can help to uncover errors that may not be obvious from simply executing every condition.
- Modified Condition: A test suite is said to achieve modified conditions if all modified conditions and decisions in the software have been evaluated during testing. This type of test design coverage extends decision coverage by testing all the conditions within a decision with all possible outcomes, taking into account the effect of modifying the conditions. This is a more comprehensive form of testing than decision coverage and can help to uncover errors that may not be obvious from simply executing every decision.
- Data Flow Coverage: A test suite is said to achieve data flow coverage if all executable paths through the software have been executed during testing. This type of test design coverage ensures that all the possible paths through the software have been executed. This is a more comprehensive form of testing than all the other types of coverage and can help to uncover errors that may not be obvious from simply executing the software.
Test Design Coverage in Software Testing
Test coverage is the degree to which a test or set of tests exercises a particular program or system. The more code that is covered by a test, the more confidence developers have that the code is free of bugs. Measuring test coverage can be difficult because it is often hard to determine what percentage of the code is actually being executed by a test. In general, however, the more code that is covered by a test, the better.
There are many different types of test coverage, but in general, test coverage is a measure of how much of the code or functionality of a system is being tested by a particular set of tests. For example, if a set of tests only covers 50% of the code, then it has 50% coverage. There are many different ways to measure test coverage, and the level of coverage that is considered acceptable varies from organization to organization. In some cases, 100% test coverage may be required, while in others, 80% may be considered adequate.
One way to think of test coverage is as a spectrum, with lower levels of coverage being less effective and higher levels being more effective. However, it is important to remember that no single level of coverage is right for all situations, and the level of coverage that is appropriate will depend on the specific system under test and the risks involved.