Fix Windows support for multiprocessing monkey patch

--HG--
branch : windows_multiprocessing_support

3 files changed, 28 insertions, 25 deletions

diff --git a/coverage/monkey.py b/coverage/monkey.py
index c4ec68c6..b896dbf5 100644
--- a/coverage/monkey.py
+++ b/coverage/monkey.py
@@ -11,6 +11,28 @@ import sys
 # monkey-patched.
 PATCHED_MARKER = "_coverage$patched"
 
+if sys.version_info >= (3, 4):
+
+    klass = multiprocessing.process.BaseProcess
+else:
+    klass = multiprocessing.Process
+
+original_bootstrap = klass._bootstrap
+
+
+class ProcessWithCoverage(klass):
+    """A replacement for multiprocess.Process that starts coverage."""
+    def _bootstrap(self):
+        """Wrapper around _bootstrap to start coverage."""
+        from coverage import Coverage
+        cov = Coverage(data_suffix=True)
+        cov.start()
+        try:
+            return original_bootstrap(self)
+        finally:
+            cov.stop()
+            cov.save()
+
 
 def patch_multiprocessing():
     """Monkey-patch the multiprocessing module.
@@ -23,26 +45,6 @@ def patch_multiprocessing():
         return
 
     if sys.version_info >= (3, 4):
-        klass = multiprocessing.process.BaseProcess
-    else:
-        klass = multiprocessing.Process
-
-    original_bootstrap = klass._bootstrap
-
-    class ProcessWithCoverage(klass):
-        """A replacement for multiprocess.Process that starts coverage."""
-        def _bootstrap(self):
-            """Wrapper around _bootstrap to start coverage."""
-            from coverage import Coverage
-            cov = Coverage(data_suffix=True)
-            cov.start()
-            try:
-                return original_bootstrap(self)
-            finally:
-                cov.stop()
-                cov.save()
-
-    if sys.version_info >= (3, 4):
         klass._bootstrap = ProcessWithCoverage._bootstrap
     else:
         multiprocessing.Process = ProcessWithCoverage
diff --git a/igor.py b/igor.py
index 409fdc91..b857fcc3 100644
--- a/igor.py
+++ b/igor.py
@@ -328,7 +328,12 @@ def print_banner(label):
     if '__pypy__' in sys.builtin_module_names:
         version += " (pypy %s)" % ".".join(str(v) for v in sys.pypy_version_info)
 
-    which_python = os.path.relpath(sys.executable)
+    try:
+        which_python = os.path.relpath(sys.executable)
+    except ValueError:
+        # On Windows having a python executable on a different drives
+        # than the sources cannot be relative
+        which_python = sys.executable
     print('=== %s %s %s (%s) ===' % (impl, version, label, which_python))
     sys.stdout.flush()
 
diff --git a/tests/test_concurrency.py b/tests/test_concurrency.py
index c6d750d0..97aa55ff 100644
--- a/tests/test_concurrency.py
+++ b/tests/test_concurrency.py
@@ -224,10 +224,6 @@ class MultiprocessingTest(CoverageTest):
 
     def setUp(self):
         super(MultiprocessingTest, self).setUp()
-        # Currently, this doesn't work on Windows, something about pickling
-        # the monkey-patched Process class?
-        if env.WINDOWS:
-            self.skip("Multiprocessing support doesn't work on Windows")
 
     def test_multiprocessing(self):
         self.make_file("multi.py", """\