A framework to test compositor nodes. The general idea is to create a node tree, render an image and compare the resulting render to a reference (i.e. expected) image.
The test can be called using
`BLENDER_VERBOSE=1 ctest -R compositor --verbose`
If a test fails, a command line is printed to make it possible for the user to inspect the nodes of the failing test.
The tests can be updated using
`BLENDER_TEST_UPDATE=1 ctest -R compositor`