CMake’s CTest assigns a dynamic COST to each test that updates each time the test is run. Kitware considers the cost test data to be undocumented behavior, so it’s not part of the CMake COST docs.

The computed test cost data is stored under ${CMAKE_BINARY_DIR}/Testing/Temporary/CTestCostData.txt This file stores data for each test in a row:

  TestName NumberOfTestRuns Cost