Regression Tests

pySpline includes a set of built-in regression tests that are used to ensure that the code reproduces a consistent set of reproducible results. It is HIGHLY recommended that the regression tests are run after installation on a new system to ensure consistency of the code build.

To run the regression tests go to the following directory:


and run the automatic testing script:


If successful, you should see the following line:

pyspline: Success!

if you don’t, then something went wrong in the test. By default an xxdiff window will appear that should quickly highlight where the discrepency is.

After running the regression tests, there will be three important files to look at:

  • pyspline_reg.ref is the reference file that contains the

    ‘truth’ values that we should reproduce

  • pyspline_ref is the generated output that is identical to the reference output except for @value lines where a discrepency has been detected. A graphical diff of pyspline_reg and pyspline_reg.ref should quickly show where the discrepancies are.

  • is the actual output of the regression run. Generally speaking there will be small discrepancies in the 15 or 16th digit which depends on the compiler. This will trigger a text-based diff program which would make it difficult to determine which values are incorrect in a file with several thousand lines.


Only lines that contain the @value magic string are actually compared by the regression tester.

Regression Test Script Help

To see a list of options for the regression test script run:

python --help

which will show:

usage: [-h] [-mode {train,compare}] [-diff_cmd DIFF_CMD]

optional arguments:
  -h, --help            show this help message and exit
  -mode {train,compare}
                      Train generates reference file. Compare runs test
  -diff_cmd DIFF_CMD    Command to run for displaying diff. Default: xxdiff
  -nodiff               Suppress displaying the comparison if not successful