Implemented a load scheduler that groups tests by scope.

setup.py

@@ -1,5 +1,13 @@
+from sys import version_info
+
 from setuptools import setup, find_packages
 
+install_requires = ['execnet>=1.1', 'pytest>=3.0.0']
+
+if version_info < (2, 7):
+    install_requires.append('ordereddict')
+
+
 setup(
     name="pytest-xdist",
     use_scm_version={'write_to': 'xdist/_version.py'},
@@ -20,7 +28,7 @@
         ],
     },
     zip_safe=False,
-    install_requires=['execnet>=1.1', 'pytest>=3.0.0'],
+    install_requires=install_requires,
     setup_requires=['setuptools_scm'],
     classifiers=[
         'Development Status :: 5 - Production/Stable',

xdist/dsession.py

@@ -5,6 +5,7 @@
 from xdist.scheduler import (
     EachScheduling,
     LoadScheduling,
+    LoadScopeScheduling,
 )
 
 
@@ -97,6 +98,7 @@ def pytest_xdist_make_scheduler(self, config, log):
         schedulers = {
             'each': EachScheduling,
             'load': LoadScheduling,
+            'loadscope': LoadScopeScheduling,
         }
         return schedulers[dist](config, log)
 

xdist/plugin.py

@@ -31,12 +31,14 @@ def pytest_addoption(parser):
                           "when crashed (set to zero to disable this feature)")
     group._addoption(
         '--dist', metavar="distmode",
-        action="store", choices=['each', 'load', 'no'],
+        action="store", choices=['each', 'load', 'loadscope', 'no'],
         dest="dist", default="no",
         help=("set mode for distributing tests to exec environments.\n\n"
               "each: send each test to all available environments.\n\n"
               "load: load balance by sending any pending test to any"
               " available environment.\n\n"
+              "loadscope: load balance by sending pending groups of tests in"
+              " the same scope to any available environment.\n\n"
               "(default) no: run tests inprocess, don't distribute."))
     group._addoption(
         '--tx', dest="tx", action="append", default=[],

xdist/scheduler/__init__.py

@@ -1,2 +1,3 @@
 from xdist.scheduler.each import EachScheduling  # noqa
 from xdist.scheduler.load import LoadScheduling  # noqa
+from xdist.scheduler.loadscope import LoadScopeScheduling  # noqa