feat: add domain models for test configuration and results

test/domain/models/iperf3_result_test.dart

@@ -0,0 +1,15 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:iperf3gui/domain/models/iperf3_result.dart';
+
+void main() {
+  group('Iperf3Result', () {
+    test('can be instantiated with raw output', () {
+      const result = Iperf3Result(
+        rawOutput: 'Test complete',
+        exitCode: 0,
+      );
+      expect(result.rawOutput, equals('Test complete'));
+      expect(result.exitCode, equals(0));
+    });
+  });
+}

test/domain/models/test_configuration_test.dart

@@ -0,0 +1,30 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:iperf3gui/domain/models/test_configuration.dart';
+
+void main() {
+  group('TestConfiguration', () {
+    test('defaults produce a valid configuration', () {
+      const config = TestConfiguration();
+      expect(config.isValid, isTrue);
+    });
+
+    test('empty server is invalid', () {
+      const config = TestConfiguration(server: '');
+      expect(config.isValid, isFalse);
+    });
+
+    test('port out of range is invalid', () {
+      expect(const TestConfiguration(port: 0).isValid, isFalse);
+      expect(const TestConfiguration(port: 65536).isValid, isFalse);
+    });
+
+    test('CLI args contain server and port', () {
+      const config = TestConfiguration(server: '192.168.1.1', port: 1234);
+      final args = config.toCliArgs();
+      expect(args, contains('-c'));
+      expect(args, contains('192.168.1.1'));
+      expect(args, contains('-p'));
+      expect(args, contains('1234'));
+    });
+  });
+}