Another try at fixing the failing tests

Author: ueman

dart/lib/src/environment_variables.dart

@@ -29,24 +29,32 @@ void setEnvironmentVariables(SentryOptions options, EnvironmentVariables vars) {
 /// In an Flutter environment these can be set via
 /// `flutter build --dart-define=VARIABLE_NAME=VARIABLE_VALUE`.
 class EnvironmentVariables {
+  static const _sentryEnvironment = 'SENTRY_ENVIRONMENT';
+  static const _sentryDsn = 'SENTRY_DSN';
+  static const _sentryRelease = 'SENTRY_RELEASE';
+  static const _sentryDist = 'SENTRY_DSN';
+
   /// `SENTRY_ENVIRONMENT`
   /// See [SentryOptions.environment]
-  String? get environment => _readString('SENTRY_ENVIRONMENT');
+  String? get environment => const bool.hasEnvironment(_sentryEnvironment)
+      ? const String.fromEnvironment(_sentryEnvironment)
+      : null;
 
   /// `SENTRY_DSN`
   /// See [SentryOptions.dsn]
-  String? get dsn => _readString('SENTRY_DSN');
+  String? get dsn => const bool.hasEnvironment(_sentryDsn)
+      ? const String.fromEnvironment(_sentryDsn)
+      : null;
 
   // `SENTRY_RELEASE`
   /// See [SentryOptions.release]
-  String? get release => _readString('SENTRY_RELEASE');
+  String? get release => const bool.hasEnvironment(_sentryRelease)
+      ? const String.fromEnvironment(_sentryRelease)
+      : null;
 
   /// `SENTRY_DIST`
   /// See [SentryOptions.dist]
-  String? get dist => _readString('SENTRY_DIST');
-
-  String? _readString(String key) =>
-      bool.fromEnvironment(key, defaultValue: false)
-          ? String.fromEnvironment(key)
-          : null;
+  String? get dist => const bool.hasEnvironment(_sentryDist)
+      ? const String.fromEnvironment(_sentryDist)
+      : null;
 }

dart/lib/src/sentry.dart

@@ -54,9 +54,6 @@ class Sentry {
 
   static Future<void> _initDefaultValues(
       SentryOptions options, AppRunner? appRunner) async {
-    var environment = options.platformChecker.environment;
-    options.environment = options.environment ?? environment;
-
     setEnvironmentVariables(options, EnvironmentVariables());
 
     // Throws when running on the browser