Use absolute path to refer to mullvad binary in test_upgrade_app

test/test-runner/src/app.rs

@@ -5,7 +5,14 @@ use test_rpc::{AppTrace, Error};
 
 /// Get the installed app version string
 pub async fn version() -> Result<String, Error> {
-    let version = tokio::process::Command::new("mullvad")
+    // The `mullvad` binary is seemingly not in PATH on Windows after upgrading the app..
+    // So, as a workaround we use the absolute path instead.
+    const MULLVAD_CLI_BIN: &str = if cfg!(target_os = "windows") {
+        r"C:\Program Files\Mullvad VPN\resources\mullvad.exe"
+    } else {
+        "mullvad"
+    };
+    let version = tokio::process::Command::new(MULLVAD_CLI_BIN)
         .arg("--version")
         .output()
         .await