pkg/linter/test/rules/cast_nullable_to_non_nullable_test.dart

// Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:analyzer/src/diagnostic/diagnostic.dart' as diag;
import 'package:test_reflective_loader/test_reflective_loader.dart';

import '../rule_test_support.dart';

void main() {
  defineReflectiveSuite(() {
    defineReflectiveTests(CastNullableToNonNullableTest);
  });
}

@reflectiveTest
class CastNullableToNonNullableTest extends LintRuleTest {
  @override
  String get lintRule => LintNames.cast_nullable_to_non_nullable;

  test_castDynamic_toNonNullable() async {
    await assertNoDiagnostics(r'''
void f(dynamic a) {
  a as String;
}
''');
  }

  test_castDynamic_toNullable() async {
    await assertNoDiagnostics(r'''
void f(dynamic a) {
  a as String?;
}
''');
  }

  test_castNullable_toNonNullable() async {
    await assertDiagnosticsFromMarkup(r'''
String? s;
var a = [!s as String!];
''');
  }

  test_castNullable_toNullable() async {
    await assertNoDiagnostics(r'''
class A {}
class B extends A {}

void f(A? a) {
  a as B?;
}
''');
  }

  test_castNullable_unresolvedType() async {
    await assertDiagnostics(
      r'''
Undefined? s;
var a = s! as String;
''',
      [
        // No lint.
        error(diag.undefinedClass, 0, 9),
      ],
    );
  }
}