[Tests] rename python tests to ensure a test*.py naming

to be compliant with unittest standard and ease discovery
ref. https://docs.python.org/3/library/unittest.html#cmdoption-unittest-discover-p

tests/python/CMakeLists.txt

@@ -2,10 +2,10 @@ SET(${PROJECT_NAME}_PYTHON_TESTS
   initialize-euler
   matrix-util
   op-point-modifier
-  test-parameter-server
-  test-smooth-reach
-  test-imports
+  parameter-server
+  smooth-reach
+  imports
   )
 FOREACH(TEST ${${PROJECT_NAME}_PYTHON_TESTS})
-  ADD_PYTHON_UNIT_TEST("py-${TEST}" "tests/python/${TEST}.py")
+  ADD_PYTHON_UNIT_TEST("py-${TEST}" "tests/python/test-${TEST}.py")
 ENDFOREACH(TEST ${${PROJECT_NAME}_PYTHON_TESTS})