TE-2659 Fix coverage with remote xdist workers

pavelib/utils/envs.py

@@ -12,6 +12,7 @@
 from lazy import lazy
 from path import Path as path
 from paver.easy import sh
+from six.moves import configparser
 
 from pavelib.utils.cmd import django_cmd
 
@@ -251,6 +252,22 @@ def get_django_setting(cls, django_setting, system, settings=None):
         )
         return unicode(value).strip()
 
+    @classmethod
+    def covered_modules(cls):
+        """
+        List the source modules listed in .coveragerc for which coverage
+        will be measured.
+        """
+        coveragerc = configparser.RawConfigParser()
+        coveragerc.read(cls.PYTHON_COVERAGERC)
+        modules = coveragerc.get('run', 'source')
+        result = []
+        for module in modules.split('\n'):
+            module = module.strip()
+            if module:
+                result.append(module)
+        return result
+
     @lazy
     def env_tokens(self):
         """
@@ -295,3 +312,15 @@ def feature_flags(self):
         Return a dictionary of feature flags configured by the environment.
         """
         return self.env_tokens.get('FEATURES', dict())
+
+    @classmethod
+    def rsync_dirs(cls):
+        """
+        List the directories that should be synced during pytest-xdist
+        execution.  Needs to include all modules for which coverage is
+        measured, not just the tests being run.
+        """
+        result = set()
+        for module in cls.covered_modules():
+            result.add(module.split('/')[0])
+        return result

pavelib/utils/test/suites/pytest_suite.py

@@ -119,6 +119,23 @@ def __init__(self, *args, **kwargs):
 
         self.processes = int(self.processes)
 
+    def _under_coverage_cmd(self, cmd):
+        """
+        If self.run_under_coverage is True, it returns the arg 'cmd'
+        altered to be run under coverage. It returns the command
+        unaltered otherwise.
+        """
+        if self.run_under_coverage:
+            if self.xdist_ip_addresses:
+                for module in Env.covered_modules():
+                    cmd.append('--cov')
+                    cmd.append(module)
+            else:
+                cmd.append('--cov')
+            cmd.append('--cov-report=')
+
+        return cmd
+
     @property
     def cmd(self):
         if self.django_toxenv:
@@ -148,12 +165,8 @@ def cmd(self):
                 xdist_string = '--tx ssh=ubuntu@{}//python="source /edx/app/edxapp/edxapp_env; ' \
                                'python"//chdir="/edx/app/edxapp/edx-platform"'.format(ip)
                 cmd.append(xdist_string)
-            already_synced_dirs = set()
-            for test_path in self.test_id.split():
-                test_root_dir = test_path.split('/')[0]
-                if test_root_dir not in already_synced_dirs:
-                    cmd.append('--rsyncdir {}'.format(test_root_dir))
-                    already_synced_dirs.add(test_root_dir)
+            for rsync_dir in Env.rsync_dirs():
+                cmd.append('--rsyncdir {}'.format(rsync_dir))
         else:
             if self.processes == -1:
                 cmd.append('-n auto')
@@ -256,12 +269,8 @@ def cmd(self):
                 xdist_string = '--tx ssh=ubuntu@{}//python="source /edx/app/edxapp/edxapp_env; ' \
                                'python"//chdir="/edx/app/edxapp/edx-platform"'.format(ip)
                 cmd.append(xdist_string)
-            already_synced_dirs = set()
-            for test_path in self.test_id.split():
-                test_root_dir = test_path.split('/')[0]
-                if test_root_dir not in already_synced_dirs:
-                    cmd.append('--rsyncdir {}'.format(test_root_dir))
-                    already_synced_dirs.add(test_root_dir)
+            for rsync_dir in Env.rsync_dirs():
+                cmd.append('--rsyncdir {}'.format(rsync_dir))
 
         if self.eval_attr:
             cmd.append("-a '{}'".format(self.eval_attr))
@@ -277,7 +286,12 @@ def _under_coverage_cmd(self, cmd):
         unaltered otherwise.
         """
         if self.run_under_coverage:
-            cmd.append('--cov')
+            if self.xdist_ip_addresses:
+                for module in Env.covered_modules():
+                    cmd.append('--cov')
+                    cmd.append(module)
+            else:
+                cmd.append('--cov')
             if self.append_coverage:
                 cmd.append('--cov-append')
             cmd.append('--cov-report=')