Static and dynamic testing are performed differently but complement each other by finding different types of defects. Also, both can have the same objectives, such as assessing the quality of the work products and identifying defects as early as possible.
Difference between Static and Dynamic Testing
| Point of Difference | Static Testing | Dynamic Testing |
|---|---|---|
| Definition | Static testing is testing a component or system at the specification or implementation level without the execution of the code of the application under development. | Dynamic testing is a software testing method that involves executing the component or system being tested. |
| Code Deployment | Code Deployment is not required in case of static testing | Dynamic testing is performed after code deployment. |
| Code Execution | In Static Testing, code is not compiled and executed. | In Dynamic Testing, Code is compiled and executed. |
| Cost | Static testing is less costly. | Bug identified during dynamic testing is expensive to fix compared to static. |
| Defect Prevention or Detection | Static testing prevents defects. | Dynamic testing is done to find and fix defects. |
| Defect Identification in Work Products | Static testing finds defects in work products directly rather than identifying failures caused by defects when the software is run. | A defect can reside in a work product for a very long time without causing a failure. The path where the defect lies may be rarely exercised or hard to reach, so it will be challenging to construct and execute a dynamic test that encounters it. Static testing may be able to find the defect with much less effort. |
| Example | Verification is an example of static testing. | A dynamic Testing example is a validation. |
| Improve Consistency & Internal Quality of Work Products | Static testing can improve work product consistency and internal quality. | Dynamic testing typically focuses on externally visible behaviors. |
| Techniques | Static testing techniques are reviews, walkthroughs, inspections, etc. | Dynamic testing consists of functional and non-functional testing and data/control flow analysis. |
| Tools | Some tools used for Static testing are: Checkstyle, Clang, Eclipse, Sonarqube, Soot, and Source meter | Some of the tools used for dynamic testing are BoundsChecker, DroidBox, Diakon, Procmon, and ValGrind. |
| When Performed | Static Testing is performed at an early stage of development. | Dynamic testing is performed at a later stage. |
Static Testing Defects
Compared with dynamic testing, typical defects that are easier and cheaper to find and fix through static testing include the following:
- Requirement defects: (e.g., inconsistencies, ambiguities, contradictions, omissions, inaccuracies, and redundancies)
- Design defects: (e.g., inefficient algorithms or database structures, high coupling, low cohesion)
- Coding defects: (e.g., variables with undefined values, variables that are declared but never used, unreachable code, duplicate code)
- Deviations from standards: (e.g., lack of adherence to coding standards)
- Incorrect interface specifications: (e.g., different units of measurement used by the calling system than by the called system)
- Security vulnerabilities: (e.g., susceptibility to buffer overflows)
- Gaps or inaccuracies in test basis traceability or coverage: (e.g., missing tests for an acceptance criterion)
- Maintainability defects: Moreover, most maintainability defects can only be found by static testing (e.g., improper modularization, poor reusability of components, and code that is difficult to analyze and modify without introducing new defects).