Add the test proposed in pypa#8796 (comment)

Author: pelson

news/8794.bugfix renamed to news/8794.bugfix.rst

@@ -327,3 +327,23 @@ def test_install_user_in_global_virtualenv_with_conflict_fails(
             f"Will not install to the user site because it will lack sys.path "
             f"precedence to pkg in {dist_location}"
         ) in result2.stderr
+
+    def test_install_user_nositepkgs_fails(
+        self, script: PipTestEnvironment, data: TestData
+    ) -> None:
+        """
+        Test that --user install fails when user site-packages are disabled.
+        """
+        run_from = data.packages.joinpath("FSPkg")
+        result = script.pip(
+            "install",
+            "--user",
+            curdir,
+            cwd=run_from,
+            expect_error=True,
+            env={"PYTHONNOUSERSITE": "1"},
+        )
+        assert (
+            "Can not perform a '--user' install. User site-packages are "
+            "disabled for this Python." in result.stderr
+        )