make sure the mockserver forked from tests uses the current installation of scrapy, not the system one

scrapy/tests/test_crawl.py

@@ -5,7 +5,7 @@ from subprocess import Popen, PIPE
 from scrapy.spider import BaseSpider
 from scrapy.http import Request
 from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
-from scrapy.utils.test import get_crawler
+from scrapy.utils.test import get_crawler, get_testenv
 
 class FollowAllSpider(BaseSpider):
 
@@ -52,7 +52,8 @@ def docrawl(spider, settings=None):
 class CrawlTestCase(TestCase):
 
     def setUp(self):
-        self.proc = Popen([sys.executable, '-u', '-m', 'scrapy.tests.mockserver'], stdout=PIPE)
+        self.proc = Popen([sys.executable, '-u', '-m', 'scrapy.tests.mockserver'],
+            stdout=PIPE, env=get_testenv())
         self.proc.stdout.readline()
 
     def tearDown(self):

scrapy/utils/test.py

@@ -67,6 +67,14 @@ def get_pythonpath():
     scrapy_path = __import__('scrapy').__path__[0]
     return os.path.dirname(scrapy_path) + sep + os.environ.get('PYTHONPATH', '')
 
+def get_testenv():
+    """Return a OS environment dict suitable to fork processes that need to import
+    this installation of Scrapy, instead of a system installed one.
+    """
+    env = os.environ.copy()
+    env['PYTHONPATH'] = get_pythonpath()
+    return env
+
 def assert_samelines(testcase, text1, text2, msg=None):
     """Asserts text1 and text2 have the same lines, ignoring differences in
     line endings between platforms