Overview
xUnit is the collective name for several unit testing frameworks that derive their structure and functionality from Smalltalk's SUnit. SUnit, designed by Kent Beck in 1998, was written in a highly structured object-oriented style, which lent easily to contemporary languages such as Java and C#. Following its introduction in Smalltalk, the framework was ported to Java by Kent Beck and Erich Gamma and gained wide popularity, eventually gaining ground in the majority of programming languages in current use. The names of many of these frameworks are a variation on "SUnit," usually replacing the "S" with the first letter (or letters) in the name of their intended language ("JUnit" for Java, "RUnit" for R, etc.). These frameworks and their common architecture are collectively known as "xUnit".
xUnit architecture
All xUnit frameworks share the following basic component architecture, with some varied implementation details.
Test runner
A test runner is an executable program that runs tests implemented using an xUnit framework and reports the test results.
Test case
A test case is the most elemental class. All unit tests are inherited from here.
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