The source code for IDV's internal SpeedTree Engine test suite is found in the installation under [SpeedTree Engine]/source/integrations/test_source/. speedtree_engine_console_test_app.pro can be used to build the test suite under Qt Creator.
Generally, the test suite exists to read from a set of SPM files and generate output files that are easy to inspect in some visualization applications. The outputs generated can be OBJ files, CSV, or even simple TXT. Output files are written to [SpeedTree Engine]/test_suite/output_data/.
The test suite contains both intensive, lengthy tests as well as straightforward example code contained in this documentation. [SpeedTree Engine]/source/integrations/test_source/learning_examples.cpp holds all of the documentation examples. The rest of the files are dedicated to stressing Engine and generating visualization output files.
[SpeedTree Engine]/test_suite/spm/ holds several test SPM and STE files, though most without their associated material files to keep the installation relatively small. The test suite code references this folder when running.
The screenshot below shows the output for some of the test functions, illustrated in an in-house visualization application at IDV.
The test suite source code is primarily included in the installation to provide more Engine usage examples.