Benington presented at US Navy's Symposium on Advanced Programming Methods for Digital Computers the SAGE project and its specification based approach where the coding phase was followed by "parameter testing" to validate component subprograms against their specification, followed then by an "assembly testing" for parts put together.
[5] Some public standards adopted end of the 60's, such as MIL-STD-483[6] and MIL-STD-490 contributed further to a wide acceptance of unit testing in large projects.
[9] Unit is defined as a single behaviour exhibited by the system under test (SUT), usually corresponding to a requirement[definition needed].
During development, a programmer may code criteria, or results that are known to be good, into the test to verify the unit's correctness.
Test scripts are generally written to prove the effective and technical operation of specific developed features in the tool, as opposed to full fledged business processes that would be interfaced by the end user, which is typically done during user acceptance testing.
If the test-script can be fully executed from start to finish without incident, the unit test is considered to have "passed", otherwise errors are noted and the user story is moved back to development in an 'in-progress' state.
[1] A unit test provides a strict, written contract that the piece of code must satisfy.
This includes both bugs in the programmer's implementation and flaws or missing parts of the specification for the unit.
The process of writing a thorough set of tests forces the author to think through inputs, outputs, and error conditions, and thus more crisply define the unit's desired behavior.
By testing individual components in isolation, developers can quickly identify and address issues, leading to faster iteration and release cycles.
The procedure is to write test cases for all functions and methods so that whenever a change causes a fault, it can be identified quickly.
[citation needed] Some programmers contend that unit tests provide a form of documentation of the code.
[citation needed] Test cases can embody characteristics that are critical to the success of the unit.
It is essential to keep careful records not only of the tests that have been performed, but also of all changes that have been made to the source code of this or any other unit in the software.
[citation needed] It is also essential to implement a sustainable process for ensuring that test case failures are reviewed regularly and addressed immediately.
Unit testing embedded system software presents a unique challenge: Because the software is being developed on a different platform than the one it will eventually run on, you cannot readily run a test program in the actual deployment environment, as is possible with desktop programs.
It is not as easy to create unit tests when a major function of the method is to interact with something external to the application.
The test suite uses assert statements to verify the expected result of various input values to the sum method.
Free tools, like those based on the xUnit framework, outsource to another system the graphical rendering of a view for human consumption.
This automated unit testing framework can be either third party, e.g., xUnit, or created within the development group.
This test will fail because either the requirement isn't implemented yet, or because it intentionally exposes a defect in the existing code.
[citation needed] Extreme programming simply recognizes that testing is rarely exhaustive (because it is often too expensive and time-consuming to be economically viable) and provides guidance on how to effectively focus limited resources.
As emergent design is heavily dependent upon refactoring, unit tests are an integral component.
Generally, frameworks are third-party; not distributed with a compiler or integrated development environment (IDE).
Their grammar allows the direct declaration of unit tests without importing a library (whether third party or standard).