What are different characteristics of resilience testing?

What does resilience mean? It’s important to know the meaning of resilience first because so many people confuse themselves with recovery, reliability and resilience. They think it’s all the same. But it is not so.

- Resilience means to recover from a change.
- It’s slightly different from recovery and reliability.
- Every software application or system has to have some degree of resilience in it in order to be more secure and recoverable and reliable.
- Resilience is a non functional requirement of a software system or application.
- Resilience testing falls under the category of non functional testing.

It is very common for the interchanging use of many non functional tests because of the overlapping in the scope between many non functional aspects or requirements.
One thing to be noted is that software performance is a broad and vast term and includes many specific requirements like scalability, reliability, compatibility, security and resilience.

Non functional testing contains the following testing techniques:
- Compliance testing
- Baseline testing
- Documentation testing
- Compatibility testing
- Load testing
- Localization testing
- Endurance testing
- Internationalization testing
- Recovery testing
- Performance testing
- Security testing
- Volume testing
- Usability testing
- Stress testing
- Scalability testing
- Resilience testing

Software system or application developers with disaster recovery plans or techniques are said to be actively and effectively engaged in reducing the risk of the software system or application crash, failure or data loss. But, the irony is that these disaster recovery plans become complacent.

This happens so because many of the software developers or testers have a false sense of security based on the existence of their disaster recovery plans. To ensure the safety of the software system or application the software developers need to test their data recovering strategies. Some software developers or testers feel this doesn’t applies to all programs because they conducted resilience testing when the software system or applications were put in place.

But one should always keep this in mind that the testing environment, the testing strategies and the range of cost effective solutions and tools available are always changing. It is required to keep pace with all these changes.

- The resilience testing strategies need to be tested and reviewed frequently in order to update for these changes.
- Some software developers and testers fear about the time and cost of test cases that give a better grade of tests and hence they are not able to put their good intention in to the practice and hence there remains a lack of resiliency in the software system or application.
- This does not necessarily means that each and every available test case should be implemented for testing the software system or application.

- There should be test plan for carrying out the resilience testing.
- A structured methodology always ensures that the amount of time consumed is minimum and the effectiveness of the testing is maximum.
- Resilience testing is some what similar to stability testing, fail over testing or recovery testing.
- Resilience testing is aimed at determining the behavior of the software system or application in the case of unreliable events, catastrophic problems and system failures, crashes and data losses.
- Resiliency is one of the core attributes of a good and reliable software system or application.
- Any software or hardware malfunctioning or failures are likely to have a considerable impact on the software system or application.

A software system needs to resilient against the following:
- Changes in requirements and specifications of the system.
- Hardware and software faults.
- Changes in data sources.

Resilience needs to be incorporated in the following stages of software development:
- Software design
- Hardware specification
- Configuration
- Documentation
- Testing