diff --git a/setup.py b/setup.py
index f28fedb85..a7b1eab00 100755
--- a/setup.py
+++ b/setup.py
@@ -95,7 +95,6 @@ def _stamp_version(filename: str) -> None:
         # "Development Status :: 7 - Inactive",
         "Environment :: Console",
         "Intended Audience :: Developers",
-        "License :: OSI Approved :: BSD License",
         "Operating System :: OS Independent",
         "Operating System :: POSIX",
         "Operating System :: Microsoft :: Windows",
diff --git a/test/test_installation.py b/test/test_installation.py
index ae6472e98..7c82bd403 100644
--- a/test/test_installation.py
+++ b/test/test_installation.py
@@ -2,6 +2,7 @@
 # 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/
 
 import ast
+import functools
 import os
 import subprocess
 
@@ -11,50 +12,22 @@
 class TestInstallation(TestBase):
     @with_rw_directory
     def test_installation(self, rw_dir):
-        venv = self._set_up_venv(rw_dir)
+        venv, run = self._set_up_venv(rw_dir)
 
-        result = subprocess.run(
-            [venv.pip, "install", "."],
-            stdout=subprocess.PIPE,
-            cwd=venv.sources,
-        )
-        self.assertEqual(
-            0,
-            result.returncode,
-            msg=result.stderr or result.stdout or "Can't install project",
-        )
+        result = run([venv.pip, "install", "."])
+        self._check_result(result, "Can't install project")
 
-        result = subprocess.run(
-            [venv.python, "-c", "import git"],
-            stdout=subprocess.PIPE,
-            cwd=venv.sources,
-        )
-        self.assertEqual(
-            0,
-            result.returncode,
-            msg=result.stderr or result.stdout or "Self-test failed",
-        )
+        result = run([venv.python, "-c", "import git"])
+        self._check_result(result, "Self-test failed")
 
-        result = subprocess.run(
-            [venv.python, "-c", "import gitdb; import smmap"],
-            stdout=subprocess.PIPE,
-            cwd=venv.sources,
-        )
-        self.assertEqual(
-            0,
-            result.returncode,
-            msg=result.stderr or result.stdout or "Dependencies not installed",
-        )
+        result = run([venv.python, "-c", "import gitdb; import smmap"])
+        self._check_result(result, "Dependencies not installed")
 
         # Even IF gitdb or any other dependency is supplied during development by
         # inserting its location into PYTHONPATH or otherwise patched into sys.path,
         # make sure it is not wrongly inserted as the *first* entry.
-        result = subprocess.run(
-            [venv.python, "-c", "import sys; import git; print(sys.path)"],
-            stdout=subprocess.PIPE,
-            cwd=venv.sources,
-        )
-        syspath = result.stdout.decode("utf-8").splitlines()[0]
+        result = run([venv.python, "-c", "import sys; import git; print(sys.path)"])
+        syspath = result.stdout.splitlines()[0]
         syspath = ast.literal_eval(syspath)
         self.assertEqual(
             "",
@@ -64,10 +37,37 @@ def test_installation(self, rw_dir):
 
     @staticmethod
     def _set_up_venv(rw_dir):
+        # Initialize the virtual environment.
         venv = VirtualEnvironment(rw_dir, with_pip=True)
+
+        # Make its src directory a symlink to our own top-level source tree.
         os.symlink(
             os.path.dirname(os.path.dirname(__file__)),
             venv.sources,
             target_is_directory=True,
         )
-        return venv
+
+        # Create a convenience function to run commands in it.
+        run = functools.partial(
+            subprocess.run,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            universal_newlines=True,
+            cwd=venv.sources,
+            env={**os.environ, "PYTHONWARNINGS": "error"},
+        )
+
+        return venv, run
+
+    def _check_result(self, result, failure_summary):
+        self.assertEqual(
+            0,
+            result.returncode,
+            msg=self._prepare_failure_message(result, failure_summary),
+        )
+
+    @staticmethod
+    def _prepare_failure_message(result, failure_summary):
+        stdout = result.stdout.rstrip()
+        stderr = result.stderr.rstrip()
+        return f"{failure_summary}\n\nstdout:\n{stdout}\n\nstderr:\n{stderr}"