Here is what they look like:

pytest test_this2.py --collect-only -q
and it will list:

test_this2.py::test_floor[integer-1-1.0]
test_this2.py::test_floor[negative--1.5--2.0]
test_this2.py::test_floor[large fraction-1.6-1]
So now you can run just the specific test:

pytest test_this2.py::test_floor[negative--1.5--2.0] test_this2.py::test_floor[integer-1-1.0]
as in the previous example.