TRX, Microsoft Visual Studio Test Results File (.trx)
The TRX Developer file format
TRX files are test result files that are created either by Microsoft Visual Studio or Microsoft MSTest. Visual Studio is a program used to develop Windows software, while MSTest is a command-line utility to run various unit tests for Visual Studio. The test results from these unit tests are saved in a TRX file and in the XML format. Thus, the TRX files help to visualize the test results and display them in Visual Studio. TRX files can also be used to save test results from older tests.
Technical details of TRX files
TRX files are not automatically created by Visual Studio or the command-line tool. By default, test results are stored in the memory of the program itself. Only when the human user gives the command to “Export Test Run Results” to Visual Studio, the data is written into the TRX files.