Grey Box Testing


It doesn't matter whether a cat is black or white so long as it catches mice.
Definitions of Gray box testing:

Gray box testing - Tests involving inputs and outputs, but test design is educated by information about the code or the program operation of a kind that would normally be out of scope of view of the tester.[Cem Kaner]

Gray box testing - Test designed based on the knowledge of algorithm, internal states, architectures, or other high -level descriptions of the program behavior. [Doug Hoffman]

Gray box testing - Examines the activity of back-end components during test case execution. Two types of problems that can be encountered during gray-box testing are:

  • A component encounters a failure of some kind, causing the operation to be aborted. The user interface will typically indicate that an error has occurred.
  • The test executes in full, but the content of the results is incorrect. Somewhere in the system, a component processed data incorrectly, causing the error in the results.
    [Elfriede Dustin. "Quality Web Systems: Performance, Security & Usability."]


    A Copy of the Lesson #289 from the book "Lessons Learned in Software Testing." by Cem Kaner, James Bach and Bret Pettichord.

    Even though you probably don't have full knowledge of the internals of the product you test, a test strategy based partly on internals is a powerful idea. We call this gray box testing. The concept is simple: If you know something about how the product works on the inside, you can test it better from the outside. This is not to be confused with white box testing, which attempts to cover the internals of the product in detail. In gray box mode, you are testing from the outside of the product, just as you do with black box, but your testing choices are informed by your knowledge of how the underlying components operate and interact. ;
    Gray box testing is especially important with Web and Internet applications, because the Internet is built around loosely integrated components that connect via relatively well-defined interfaces. Unless you understand the architecture of the Net, your testing will be skin deep. Hung Nguyen's Testing Applications on the Web (2000) is a good example of gray box test strategy applied to the Web.
    On this page I put a short description of Grey box software testing.

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