Move ansible-test unit coverage code into plugin.

test/runner/lib/executor.py

@@ -1333,6 +1333,17 @@ def command_units(args):
             'test/results/junit/python%s-units.xml' % version,
         ]
 
+        plugins = []
+
+        if args.coverage:
+            plugins.append('ansible_pytest_coverage')
+
+        if plugins:
+            env['PYTHONPATH'] += ':%s' % os.path.join(INSTALL_ROOT, 'test/units/pytest/plugins')
+
+            for plugin in plugins:
+                cmd.extend(['-p', plugin])
+
         if args.collect_only:
             cmd.append('--collect-only')
 

test/units/pytest/plugins/ansible_pytest_coverage.py

@@ -1,22 +1,24 @@
 """Monkey patch os._exit when running under coverage so we don't lose coverage data in forks, such as with `pytest --boxed`."""
-import gc
-import os
+from __future__ import (absolute_import, division, print_function)
 
-try:
+
+def pytest_configure():
+    try:
         import coverage
-except ImportError:
+    except ImportError:
         coverage = None
 
-try:
+    try:
         test = coverage.Coverage
-except AttributeError:
+    except AttributeError:
         coverage = None
 
-
-def pytest_configure():
     if not coverage:
         return
 
+    import gc
+    import os
+
     coverage_instances = []
 
     for obj in gc.get_objects():