NUnit Gui Runner

The nunit.exe program is a graphical runner. It shows the tests in an explorer-like browser window and provides a visual indication of the success or failure of the tests. It allows you to selectively run single tests or suites and reloads automatically as you modify and re-compile your code. The following is a screenshot of NUnit running the same mock-assembly.dll shown in the previous example.

Tree Display

This version of NUnit uses symbols in the test tree, which allow those who are unable to easily distinguish colors to determine the test status. Successful tests are colored green, with a check mark. Tests that are ignored are marked with a yellow circle, containing a question mark. If any tests had failed, they would be marked red, with an X symbol.

In this example, there were a total of 11 test cases, but one of them was not counted because it was marked Explicit. Note that it is shown as a gray circle in the tree. Of the remaining 10 tests, 5 were run successfully and 5 were ignored.

The symbols shown in the tree are actually files in the NUnit bin directory. These files are named Success.jpg, Failure.jpg and Ignored.jpg and may be modified or replaced by the user.

Progress Bar

The progress bar shows the progress of the test. It is colored according to the "worst" result obtained: red if there were any failures, yellow if some tests were ignored and green for success.

Result Tabs

The tabs along the bottom of the display show the results of running a test. The Errors and Failures tab displays the error message and stack trace for both unexpected exceptions and assertion failures. The Tests Not Run tab provides a list of all tests that were selected for running but were not run, together with the reason. The remaining tabs display text output from the tests. In the image above, there are four of them: Console.Out, Console.Error, Trace and Log. This is the default display, but these output tabs are actually under user control and may be removed or modified or have new tabs added. For more information, see the documentation for the Options Dialog.


With the release of NUnit 2.4, an alternate "mini-gui" is also available. It may be selected from the View menu. The following screenshot shows the mini gui displaying the NUnit tests.

NUnit on 64-Bit Platforms

The .NET 2.0 version of nunit.exe is built using /platform:anycpu, which causes it to be jit-compiled to 32-bit code on a 32-bit system and 64-bit code on a 64 bit system. This causes an exception when NUnit is used to test a 32-bit application on a 64-bit system. To avoid this problem, use nunit-x86.exe , which is built using /platform:x86, when testing 32-bit code on a 64-bit system.