Make installing pytest-runner contingent on running tests

This monkeypatches several changes from [PyCQA/mccabe](https://github.com/PyCQA/mccabe/blob/master/setup.py)
over to the pylint repo, since the pattern was equivalent between
the two projects.

Signed-off-by: Enji Cooper <yaneurabeya@gmail.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index b46d40917..3a98994ff 100644
--- a/setup.py
+++ b/setup.py
@@ -62,6 +62,10 @@ else:
     long_description = ""
 
 
+needs_pytest = set(['pytest', 'test', 'ptr']).intersection(sys.argv)
+pytest_runner = ['pytest-runner'] if needs_pytest else []
+
+
 def ensure_scripts(linux_scripts):
     """Creates the proper script names required for each platform
     (taken from 4Suite)
@@ -143,7 +147,7 @@ def install(**kwargs):
         extras_require=extras_require,
         test_suite="test",
         python_requires=">=3.5.*",
-        setup_requires=["pytest-runner"],
+        setup_requires=pytest_runner,
         tests_require=["pytest"],
         **kwargs
     )