--- a/docs/vcssync/development.rst
+++ b/docs/vcssync/development.rst
@@ -16,9 +16,9 @@ Then activate the environment in your sh
 
    $ source activate venv/vcssync/bin/activate
 
 Running Tests
 =============
 
 To run the vcssync tests, run::
 
-   $ ./run-tests -j4 vcssync
+   $ ./run-tests -j4

--- a/run-tests
+++ b/run-tests
@@ -122,17 +122,17 @@ if __name__ == '__main__':
         hg_harness_args.extend(['--with-hg', hg])
 
     # Always produce an XUnit result file.
     hg_harness_args.extend(['--xunit',
         os.path.join(HERE, 'coverage', 'results.xml')])
 
     extensions = get_extensions(EXTDIR)
 
-    test_files = get_test_files(extensions)
+    test_files = get_test_files(extensions, venv_name)
     extension_tests = test_files['extension']
     unit_tests = test_files['unit']
     hook_tests = test_files['hook']
 
     possible_tests = [os.path.normpath(os.path.abspath(a))
                       for a in extra[1:] if not a.startswith('-')]
     # Filter out arguments that might be tests.
     hg_harness_args = [a for a in hg_harness_args

--- a/testing/vcttesting/testing.py
+++ b/testing/vcttesting/testing.py
@@ -21,23 +21,33 @@ ROOT = os.path.normpath(os.path.join(HER
 PYTHON_COVERAGE_DIRS = (
     'hgext',
     'pylib',
     'hghooks',
     'vcssync',
 )
 
 # Directories containing Python unit tests.
-UNIT_TEST_DIRS = [
-    'autoland/tests',
-    'git/tests',
-    'hgserver/tests',
-    'pylib',
-    'vcssync/tests',
-]
+UNIT_TEST_DIRS = {
+    'autoland/tests': {
+        'venvs': {'global'},
+    },
+    'git/tests': {
+        'venvs': {'global',},
+    },
+    'hgserver/tests': {
+        'venvs': {'global',},
+    },
+    'pylib': {
+        'venvs': {'global',},
+    },
+    'vcssync/tests': {
+        'venvs': {'vcssync',},
+    },
+}
 
 # Directories whose Python unit tests we should ignore.
 UNIT_TEST_IGNORES = (
     'pylib/Bugsy',
     'pylib/flake8',
     'pylib/mccabe',
     'pylib/pycodestyle',
     'pylib/pyflakes',
@@ -103,28 +113,38 @@ def get_extensions(extdir):
                 value = value.strip().strip("'").strip('"').strip()
                 e['testedwith'] = set(value.split())
 
         m[d] = e
 
     return m
 
 
-def get_test_files(extensions):
+def get_test_files(extensions, venv):
     extension_tests = []
-    for e in extensions.values():
-        extension_tests.extend(e['tests'])
+
+    if venv == 'global':
+        for e in extensions.values():
+            extension_tests.extend(e['tests'])
 
-    hooks_test_dir = os.path.join(ROOT, 'hghooks', 'tests')
-    hook_tests = [os.path.join(hooks_test_dir, f)
-                   for f in os.listdir(hooks_test_dir)
-                   if is_test_filename(f)]
+    hook_tests = []
+
+    if venv == 'global':
+        hooks_test_dir = os.path.join(ROOT, 'hghooks', 'tests')
+        hook_tests = [os.path.join(hooks_test_dir, f)
+                       for f in os.listdir(hooks_test_dir)
+                       if is_test_filename(f)]
 
     unit_tests = []
-    for base in UNIT_TEST_DIRS:
+    for base, settings in sorted(UNIT_TEST_DIRS.items()):
+        # Only add tests from path if marked as compatible with the
+        # current virtualenv.
+        if venv not in settings['venvs']:
+            continue
+
         base = os.path.join(ROOT, base)
         for root, dirs, files in os.walk(base):
             relative = root[len(ROOT) + 1:]
             if relative.startswith(UNIT_TEST_IGNORES):
                 continue
 
             for f in files:
                 if f.startswith('test') and f.endswith('.py'):