Add system test

Author: konstin

.github/workflows/ci.yml

@@ -1582,6 +1582,20 @@ jobs:
       - name: "Validate global Python install"
         run: python ./scripts/check_system_python.py --uv ./uv.exe
 
+      # NB: Run this last, we are modifying the registry
+      - name: "Test PEP 514 registration"
+        run: |
+          ./uv.exe python install --preview 3.11
+          ./uv.exe python install --preview 3.12
+          ./uv.exe python install --preview 3.13
+          Get-ChildItem -Path "HKCU:\Software\Python" -Recurse
+          py --list-paths
+          ./uv.exe python uninstall --preview 3.11
+          Get-ChildItem -Path "HKCU:\Software\Python" -Recurse
+          py --list-paths
+          ./uv.exe python uninstall --preview --all
+          Get-ChildItem -Path "HKCU:\Software\Python" -Recurse
+
   system-test-windows-python-313:
     timeout-minutes: 10
     needs: build-binary-windows

crates/uv/src/commands/python/install.rs

@@ -337,9 +337,9 @@ pub(crate) async fn install(
             &mut errors,
         )?;
 
-        #[cfg(windows)]
-        {
-            if preview.is_enabled() {
+        if preview.is_enabled() {
+            #[cfg(windows)]
+            {
                 uv_python::windows_registry::create_registry_entry(installation, &mut errors)?;
             }
         }