test(self-update): ensure the resolution of #3739

Author: rami3l

tests/suite/cli_self_upd.rs

@@ -300,11 +300,33 @@ info: downloading self-update
 
     update_setup(&|config, _| {
         config.expect_ok(&["rustup-init", "-y", "--no-modify-path"]);
+
+        #[cfg(windows)]
+        const RUSTUP_UNINSTALL_ENTRY: &str =
+            r"Software\Microsoft\Windows\CurrentVersion\Uninstall\Rustup";
+
+        #[cfg(windows)]
+        winreg::RegKey::predef(winreg::enums::HKEY_CURRENT_USER)
+            .open_subkey(RUSTUP_UNINSTALL_ENTRY)
+            .unwrap()
+            .delete_value("DisplayVersion")
+            .unwrap();
+
         config.expect_ok_ex(
             &["rustup", "self", "update"],
             &format!("  rustup updated - {version} (from {version})\n\n",),
             &expected_output,
-        )
+        );
+
+        #[cfg(windows)]
+        assert_eq!(
+            winreg::RegKey::predef(winreg::enums::HKEY_CURRENT_USER)
+                .open_subkey(RUSTUP_UNINSTALL_ENTRY)
+                .unwrap()
+                .get_value::<String, _>("DisplayVersion")
+                .unwrap(),
+            version,
+        );
     });
 }