Software Testing is the system with the intent of finding errors andit aims at evaluating an attribute or capability of a program or system and determining that it meets its required results.
Most of the defects in software are design errors, not manufacturing defects. Software does not suffer from corrosion, wear-and-tear generally it will not change until it upgrades.
Discovering the design defects in software, is equally difficult, for the same reason of complexity. Because software and any digital systems are not continuous, testing boundary values are not sufficient to guarantee correctness. All the possible values need to be tested and verified, but complete testing is infeasible. If inputs from the real world are involved, the problem will get worse, because timing and unpredictable environmental effects and human interactions are all possible input parameters under consideration.
Testing is an integral part in software development. It is broadly deployed in every phase in the software development cycle. Typically, more than 50% percent of the development time is spent in testing.
A Test caseis a software testing document, which consists of event, action, input, output, expected result, and actual result.
The Test script is the combination of a test case, test procedure, and test data. Initially the term was derived from the product of work created by automated regression test tools. Today, test scripts can be manual, automated, or a combination of both.
The most common term for a collection of test cases is Test suite. The test suite often also contains more detailed instructions or goals for each collection of test cases.
A test specification is called a test plan.
Testing is usually performed for the following purposes:
- To improve quality.
Quality means the conformance to the specified design requirement. Debugging, a narrow view of software testing, is performed heavily to find out design defects by the programmer. The imperfection of human nature makes it almost impossible to make a moderately complex program correct the first time. Finding the problems and get them fixed is the purpose of debugging in programming phase.
- For Verification & Validation (V&V)
Another important purpose of testing is verification and validation (V&V). Testers can make claims based on interpretations of the testing results, which either the product works under certain situations, or it does not work. We can also compare the quality among different products under the same specification, based on results from the same test.
- For reliability estimation
Software reliability has important relations with many aspects of software, including the structure, and the amount of testing it has been subjected to. Based on an operational profile (an estimate of the relative frequency of use of various inputs to the program testing can serve as a statistical sampling method to gain failure data for reliability estimation.
When to stop testing?
Testing is potentially endless. We can not test till all the defects are unearthed and removed — it is simply impossible. At some point, we have to stop testing and ship the software. The question is when.
Realistically, testing is a trade-off between budget, time and quality. It is driven by profit models. The pessimistic, and unfortunately most often used approach is to stop testing whenever some, or any of the allocated resources time, budget, or test cases are exhausted.
The optimistic stopping rule is to stop testing when either reliability meets the requirement, or the benefit from continuing testing cannot justify the testing cost. This will usually require the use of reliability models to evaluate and predict reliability of the software under test. Each evaluation requires repeated running of the following cycle: failure data gathering modeling prediction.
Types oftesting
Black box testing - Internal system design is not considered in this type of testing. Tests are based on requirements and functionality.
White box testing - This testing is based on knowledge of the internal logic of an application’s code. Also known as Glass box Testing. Internal software and code working should be known for this type of testing. Tests are based on coverage of code statements, branches, paths, conditions.
Unit testing - Testing of individual software components or modules. Typically done by the programmer and not by testers, as it requires detailed knowledge of the internal program design and code. may require developing test driver modules or test harnesses.
Incremental integration testing - Bottom up approach for testing i.e continuous testing of an application as new functionality is added; Application functionality and modules should be independent enough to test separately. done by programmers or by testers.
Integration testing - Testing of integrated modules to verify combined functionality after integration. Modules are typically code modules, individual applications, client and server applications on a network, etc. This type of testing is especially relevant to client/server and distributed systems.
Functional testing - This type of testing ignores the internal parts and focus on the output is as per requirement or not. Black-box type testing geared to functional requirements of an application.
System testing - Entire system is tested as per the requirements. Black-box type testing that is based on overall requirements specifications, covers all combined parts of a system.
End-to-end testing - Similar to system testing, involves testing of a complete application environment in a situation that mimics real-world use, such as interacting with a database, using network communications, or interacting with other hardware, applications, or systems if appropriate.
Sanity testing - Testing to determine if a new software version is performing well enough to accept it for a major testing effort. If application is crashing for initial use then system is not stable enough for further testing and build or application is assigned to fix.
Regression testing - Testing the application as a whole for the modification in any module or functionality. Difficult to cover all the system in regression testing so typically automation tools are used for these testing types.
Acceptance testing -Normally this type of testing is done to verify if system meets the customer specified requirements. User or customer do this testing to determine whether to accept application.
Load testing - Its a performance testing to check system behavior under load. Testing an application under heavy loads, such as testing of a web site under a range of loads to determine at what point the system’s response time degrades or fails.
Stress testing - System is stressed beyond its specifications to check how and when it fails. Performed under heavy load like putting large number beyond storage capacity, complex database queries, continuous input to system or database load.
Performance testing - Term often used interchangeably with ’stress’ and ‘load’ testing. To check whether system meets performance requirements. Used different performance and load tools to do this.
Usability testing - User-friendliness check. Application flow is tested, Can new user understand the application easily, Proper help documented whenever user stuck at any point. Basically system navigation is checked in this testing.
Install/uninstall testing - Tested for full, partial, or upgrade install/uninstall processes on different operating systems under different hardware, software environment.
Recovery testing - Testing how well a system recovers from crashes, hardware failures, or other catastrophic problems.
Security testing - Can system be penetrated by any hacking way. Testing how well the system protects against unauthorized internal or external access. Checked if system, database is safe from external attacks.
Compatibility testing - Testing how well software performs in a particular hardware/software/operating system/network environment and different combination s of above.
Comparison testing - Comparison of product strengths and weaknesses with previous versions or other similar products.
Alpha testing - In house virtual user environment can be created for this type of testing. Testing is done at the end of development. Still minor design changes may be made as a result of such testing.
Beta testing - Testing typically done by end-users or others. Final testing before releasing application for commercial purpose.
