Gray Box Testing in Software Testing
Grey box testing is also known as translucent testing. Grey box testing involves having knowledge of internal data structures and algorithms for test design purposes while performing these tests at the user, or black box, level. The tester often has access to both “source code and executable binary”. Gray box testing may also include reverse engineering, for example, boundary values or to determine the error messages.
Manipulation and formatting of input data do not qualify as output grey boxes, because the input and output are clearly outside the “black box” we are calling the system under test. This distinction is especially important when testing integration between two modules of code written by two different developers, where only the interfaces are exposed to the test.
By knowing the fundamental concepts of how the software works, the tester makes better-informed testing choices when testing software externally. Typically, a grey box tester will be allowed to set up an isolated testing environment with activities such as database seeding.
The tester can observe the state of the product being tested after performing certain operations such as executing SQL statements against the database and then completing queries to ensure that the expected changes are made. Grey box testing implements intelligent test scenarios based on limited information. This would particularly apply to data type handling, exception handling, etc.
Why Grey box testing is required?
Grey box testing is beneficial because it takes the straightforward techniques of black box testing and combines them with code-targeted systems in white box testing.
Gray box testing is based on requirement test case generation because it presents all conditions before testing the program using the assertion method. A requirement specification language is used to understand the requirements and verify their validity.
Grey box testing assumptions for object-oriented software.
Object-oriented software consists primarily of objects. where objects are single indivisible units that contain executable code and/or data, below are some of the assumptions that are required to use gray box testing.
- Activation of methods
- State Reporting in Class Under Test (CUT)
- Report testing is inherent in the class Under Test
Grey Box Testing Examples
- Architectural model
- Unified Modeling Language – UML Design Model
- Finite state machine-state model
Grey Box Testing Technique
Cem Kaner defines gray box testing as involving inputs and outputs, but the test design is informed by code or knowledge of the type of program operation that the tester typically is Out of sight. Grey box testing techniques are:
- Metrics Testing: The status report of the project.
- Regression Testing: This means re-running the test cases if new changes are made.
- Pattern Testing: Verify good application for its design or architecture and patterns.
- Orthogonal array testing: used as a subset of all possible combinations.
Grey Box Testing Effects
Positive effects
- Offers Combined Benefits: Gray box testing is a combination of white box and black box testing, it provides the benefits of both testing.
- Non-intrusive: It is based on functional specification, and architectural view and not on source code or binaries which also makes it non-intrusive.
- Intelligent Test Authoring: Grey box Tester handles intelligent test scenarios, for example, data type handling, communication protocols, and exception handling.
- Unbiased Testing: Despite all the above advantages and features, grey box testing maintains a testing boundary between the tester and the developer.
Negative effects
- Partial code coverage: In gray box testing, source code or binaries are missing because there is limited access to the internals or structures of the applications resulting in limited access to code path traversal.
- Defect detection: In distributed applications, it is challenging to combine defect detection. Still, grey box testing is a boon for determining how well these systems handle exceptions and how well these exceptions are handled in distributed systems with Web services environments.
Applications of Grey Box Testing
Grey box testing is suitable for web applications. Web applications span a network or system. It is not possible to use white box testing due to the absence of source code or binaries. Black box testing is not used only because of the contract between the customer and the developer, so it is more efficient to use grey box testing because the important information is available in Web Services Description Language (WSDL).
Grey box testing is suitable for functional or business domain testing. Functional testing mainly tests user interaction with external systems. Gray box testing is suitable for functional testing because of its features. It also helps to verify that the software meets the requirements defined for the software.
Grey Box Testing Future scope
The distributed nature of Web services allows grey box testing to detect defects in service-oriented architecture (SOA). As we know, white box testing is not suitable for web services as it deals directly with the internal structure. White box testing can be used for state-of-the-art methods. For example, message mutation generates automated tests for large arrays to flow without exception-handling states, source code, or binaries. Such a strategy is useful for bringing gray box testing closer to the results of white box testing.
Difference Between White Box Testing, Black Box Testing, And Grey Box Testing
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