Env.ServerIsLocal() throws NullReferenceException when DEV env var is unset

Start in test/integration/helpers/Env.cs, read IsTrue and ServerIsLocal, then reproduce with env.json setting DEV to false and the DEV environment variable unset. Run the Android or iOS functional tests, and consider the issue done when an unset DEV value returns false without an exception and the affected fixtures complete setup.

Description

Env.ServerIsLocal() throws a NullReferenceException in CI (and locally, whenever env.json declares "DEV": "false" and the DEV environment variable isn't set), which fails OneTimeSetUp for every integration test fixture that relies on it.

Root cause

test/integration/helpers/Env.cs:

private static bool IsTrue(object val)
{
    val = val?.ToString().ToLowerInvariant().Trim();
    return val.Equals("true") || val.Equals("1");
}

public static bool ServerIsLocal()
{
    Init();
    return (_env.ContainsKey("DEV") && IsTrue(_env["DEV"])) || IsTrue(Environment.GetEnvironmentVariable("DEV"));
}

val?.ToString() correctly short-circuits to null when val is null, but the reassigned val is then used in val.Equals(...) unconditionally — so if it's still null, this throws NullReferenceException instead of returning false.

ServerIsLocal() hits this whenever:

1. env.json's "DEV" value is falsy (e.g. "false", as set by CI in .github/workflows/functional-test.yml), so the left side of || is false, and
2. the DEV environment variable is not set (the normal case in CI), so Environment.GetEnvironmentVariable("DEV") returns null and IsTrue(null) throws.

Impact

Every fixture that calls Env.ServerIsLocal() in its [OneTimeSetUp] fails immediately with NullReferenceException, failing all tests in that fixture. Confirmed in a recent CI run for both platforms, e.g.:

• Android: Android/Device/App/AppTests.cs, Android/Device/NetworkTests.cs, Android/Device/PerformanceDataTests.cs, Android/Session/Logs/LogcatBroadcastTests.cs
• iOS: IOS/Session/Logs/SyslogBroadcastTests.cs

Stack trace (identical shape on both platforms):

System.NullReferenceException : Object reference not set to an instance of an object.
   at Appium.Net.Integration.Tests.helpers.Env.IsTrue(Object val) in .../test/integration/helpers/Env.cs:line 53
   at Appium.Net.Integration.Tests.helpers.Env.ServerIsLocal() in .../test/integration/helpers/Env.cs:line 65
   at Appium.Net.Integration.Tests.Android.Device.App.AppTests.SetUp() in .../test/integration/Android/Device/App/AppTests.cs:line 21

Reference run: https://github.com/appium/dotnet-client/actions/runs/35200826871 (jobs android-tests and ios-tests).

Note: this bug was previously masked in CI because env.json never actually made it into the test output directory (a separate bug, fixed in #1130) — Env.Init()'s try/catch silently fell back to its default _env dict where DEV is true, so ServerIsLocal() short-circuited on the first operand and never reached the crashing branch. Now that env.json loads correctly, this latent bug surfaces.

Suggested fix

Guard against val being null after the null-conditional chain, e.g.:

private static bool IsTrue(object val)
{
    var str = val?.ToString()?.ToLowerInvariant().Trim();
    return str == "true" || str == "1";
}

Reproduction

Run the Android or iOS functional test suite in CI (or locally with env.json present and "DEV": "false", and no DEV environment variable set) — any fixture calling Env.ServerIsLocal() fails OneTimeSetUp.