pkg/linter/test/rules/prefer_null_aware_operators_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:test_reflective_loader/test_reflective_loader.dart';

import '../rule_test_support.dart';

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

@reflectiveTest
class PreferNullAwareOperatorsTest extends LintRuleTest {
  @override
  String get lintRule => LintNames.prefer_null_aware_operators;

  test_identifierEqualEqualNull_null_elseBinaryExpression() async {
    await assertNoDiagnostics(r'''
void f(A? a) {
  a == null ? null : a.b + 10;
}

abstract class A {
  int get b;
}
''');
  }

  test_identifierEqualEqualNull_null_elseMethodCall() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  a == null ? null : a.b();
}

abstract class A {
  void b();
}
''',
      [lint(17, 24)],
    );
  }

  test_identifierEqualEqualNull_null_elsePrefixedIdentifier() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  a == null ? null : a.b;
}

abstract class A {
  int get b;
}
''',
      [lint(17, 22)],
    );
  }

  test_identifierEqualEqualNull_null_elsePropertyAccess() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  a == null ? null : a.b.c;
}

abstract class A {
  A get b;
  int get c;
}
''',
      [lint(17, 24)],
    );
  }

  test_identifierEqualEqualNull_unrelatedBranch() async {
    // This is covered by another rule.
    await assertNoDiagnostics(r'''
void f(int? a, int b) {
  a == null ? b : a;
}
''');
  }

  test_identifierEqualEqualNull_unrelatedBranches() async {
    await assertNoDiagnostics(r'''
void f(int? a, int b) {
  a == null ? b.isEven : null;
}
''');
  }

  test_identifierNotEqualNull_prefixedIdentifier_elseNull() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  a != null ? a.b : null;
}

abstract class A {
  int get b;
}
''',
      [lint(17, 22)],
    );
  }

  test_identifierNotEqualNull_prefixedIdentifier_null() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  a != null ? a.b : null;
}

abstract class A {
  int get b;
}
''',
      [lint(17, 22)],
    );
  }

  test_nullEqualEqualIdentifier_null_elseMethodInvocation() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  null == a ? null : a.b();
}

abstract class A {
  void b();
}
''',
      [lint(17, 24)],
    );
  }

  test_nullEqualEqualIdentifier_null_elsePrefixedIdentifier() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  null == a ? null : a.b;
}

abstract class A {
  int get b;
}
''',
      [lint(17, 22)],
    );
  }

  test_nullEqualEqualPrefixedIdentifier_null_elsePropertyAccess() async {
    await assertDiagnostics(
      r'''
void f(A a) {
  null == a.b ? null : a.b!.c;
}

abstract class A {
  A? get b;
  int get c;
}
''',
      [lint(16, 27)],
    );
  }

  test_nullNotEqualIdentifier_prefixedIdentifier_elseNull() async {
    await assertDiagnostics(
      r'''
void f(A? a) {
  null != a ? a.b : null;
}

abstract class A {
  int get b;
}
''',
      [lint(17, 22)],
    );
  }

  test_nullNotEqualPrefixedIdentifier_propertyAccess_elseNull() async {
    await assertDiagnostics(
      r'''
void f(A a) {
  null != a.b ? a.b!.c : null;
}

abstract class A {
  A? get b;
  int get c;
}
''',
      [lint(16, 27)],
    );
  }

  test_prefixedIdentifierEqualEqualNull_null_elseMethodInvocation() async {
    await assertDiagnostics(
      r'''
void f(A a) {
  a.b == null ? null : a.b!.c();
}

abstract class A {
  A? get b;
  void c();
}
''',
      [lint(16, 29)],
    );
  }

  test_prefixedIdentifierEqualEqualNull_null_elsePropertyAccess() async {
    await assertDiagnostics(
      r'''
void f(A a) {
  a.b == null ? null : a.b!.c;
}

abstract class A {
  A? get b;
  int get c;
}
''',
      [lint(16, 27)],
    );
  }

  test_prefixedIdentifierNotEqualNull_prefixedIdentifier_elseNull() async {
    await assertNoDiagnostics(r'''
void f(A a) {
  a.b != null ? a.b : null;
}

abstract class A {
  int? get b;
}
''');
  }

  test_prefixedIdentifierNotEqualNull_propertyAccess_elseNull() async {
    await assertDiagnostics(
      r'''
void f(A a) {
  a.b != null ? a.b!.c : null;
}

abstract class A {
  A? get b;
  int get c;
}
''',
      [lint(16, 27)],
    );
  }
}