How could I get "spatialdata" in order to run test code for pylith?

The Docker container contains a built version of PyLith. It provides the same thing as the binary (including dependencies), but requires doing your work inside the container. The binary installs without a container, so it is easier to integrate with other tools.

PyLith does not run within an IDE. Please see the manual for examples on how to install and run PyLith, including many examples.