diff --git a/test/11_dependency_versions/cibuildwheel_test.py b/test/11_dependency_versions/cibuildwheel_test.py
index 7013ee37..05f9e359 100644
--- a/test/11_dependency_versions/cibuildwheel_test.py
+++ b/test/11_dependency_versions/cibuildwheel_test.py
@@ -96,6 +96,7 @@ def test_dependency_constraints_file(tmp_path):
         'pip': '19.2.3',
         'setuptools': '43.0.0',
         'wheel': '0.33.6',
+        'virtualenv': '16.7.8',
     }
 
     constraints_file = tmp_path / 'constraints.txt'
@@ -104,6 +105,7 @@ def test_dependency_constraints_file(tmp_path):
             pip=={pip}
             setuptools=={setuptools}
             wheel=={wheel}
+            virtualenv=={virtualenv}
         '''.format(**tool_versions)
     ))
 
diff --git a/test/11_dependency_versions/setup.py b/test/11_dependency_versions/setup.py
index 209f45b0..bf0b1864 100644
--- a/test/11_dependency_versions/setup.py
+++ b/test/11_dependency_versions/setup.py
@@ -1,8 +1,25 @@
+import os
+import subprocess
 from setuptools import (
     Extension,
     setup,
 )
 
+versions_output_text = subprocess.check_output(
+    ['pip', 'freeze', '--all', '-qq'],
+    universal_newlines=True,
+)
+versions = versions_output_text.strip().splitlines()
+
+# `versions` now looks like:
+# ['pip==x.x.x', 'setuptools==x.x.x', 'wheel==x.x.x']
+
+for package_name in ['pip', 'setuptools', 'wheel']:
+    env_name = 'EXPECTED_{}_VERSION'.format(package_name.upper())
+    expected_version = os.environ[env_name]
+
+    assert '{}}=={}'.format(package_name, expected_version) in versions
+
 setup(
     name="spam",
     ext_modules=[Extension('spam', sources=['spam.c'])],