Tests:

• start and stop an SP and verify that documents are correctly streamed from source to sink
• modify an SP pipeline and verify that the updated pipeline goes into effect
• sample an SP and verify that docs are correctly output in the shell
• get stats for a running SP and verify that they display properly
• create an interactive SP with .process() and verify that docs are correctly output in the shell
• verify creating and dropping SPs work using test setup/teardown