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PiotrRogulskiPiotrRogulski
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Add the prefer_equatable_mixin lint (#503)
* Add the `prefer_equatable_mixin` lint * More tests * Update correction message
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‎packages/leancode_lint/README.md‎

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@@ -585,6 +585,44 @@ class MyWidget extends StatelessWidget {
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None
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### `prefer_equatable_mixin`
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**DO** mix in `EquatableMixin` instead of extending `Equatable`.
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**BAD:**
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```dart
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import 'package:equatable/equatable.dart';
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class Foobar extends Equatable {
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const Foobar(this.value);
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final int value;
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@override
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List<Object?> get props => [value];
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}
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```
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**GOOD:**
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```dart
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import 'package:equatable/equatable.dart';
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class Foobar with EquatableMixin {
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const Foobar(this.value);
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final int value;
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@override
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List<Object?> get props => [value];
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}
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```
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#### Configuration
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None.
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## Assists
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Assists are IDE refactorings not related to a particular issue. They can be triggered by placing your cursor over a relevant piece of code and opening the code actions dialog. For instance, in VSCode this is done with <kbd>ctrl</kbd>+<kbd>.</kbd> or <kbd>⌘</kbd>+<kbd>.</kbd>.
@@ -631,4 +669,4 @@ We are **top-tier experts** focused on Flutter Enterprise solutions.
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[leancode-landing]: https://leancode.co/?utm_source=github.com&utm_medium=referral&utm_campaign=leancode-lint
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[leancode-estimate]: https://leancode.co/get-estimate?utm_source=github.com&utm_medium=referral&utm_campaign=leancode-lint
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[leancode-packages]: https://pub.dev/packages?q=publisher%3Aleancode.co&sort=downloads
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[patrol-landing]: https://patrol.leancode.co/?utm_source=github.com&utm_medium=referral&utm_campaign=leancode-lint
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[patrol-landing]: https://patrol.leancode.co/?utm_source=github.com&utm_medium=referral&utm_campaign=leancode-lint

‎packages/leancode_lint/lib/plugin.dart‎

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@@ -10,6 +10,7 @@ import 'package:leancode_lint/src/lints/avoid_single_child_in_multi_child_widget
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import 'package:leancode_lint/src/lints/catch_parameter_names.dart';
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import 'package:leancode_lint/src/lints/constructor_parameters_and_fields_should_have_the_same_order.dart';
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import 'package:leancode_lint/src/lints/hook_widget_does_not_use_hooks.dart';
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import 'package:leancode_lint/src/lints/prefer_equatable_mixin.dart';
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import 'package:leancode_lint/src/lints/prefix_widgets_returning_slivers.dart';
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import 'package:leancode_lint/src/lints/start_comments_with_space.dart';
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import 'package:leancode_lint/src/lints/use_align.dart';
@@ -64,8 +65,13 @@ final class LeanCodeLintPlugin extends Plugin {
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UseDedicatedMediaQueryMethods.code,
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ReplaceMediaQueryOfWithDedicatedMethodFix.new,
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)
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..registerWarningRule(PreferEquatableMixin())
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..registerFixForRule(
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PreferEquatableMixin.code,
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ConvertToEquatableMixin.new,
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)
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// TODO: uncomment when `prefer_center_over_align` is migrated
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// ..registerAssist(PreferCenterOverAlign())
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// ..registerWarningRule(PreferCenterOverAlign())
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..registerAssist(ConvertRecordIntoNominalType.new)
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..registerAssist(ConvertPositionalToNamedFormal.new)
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..registerAssist(ConvertIterableMapToCollectionFor.new);

‎packages/leancode_lint/lib/src/lints/prefer_equatable_mixin.dart‎

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import 'package:analysis_server_plugin/edit/dart/correction_producer.dart';
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import 'package:analysis_server_plugin/edit/dart/dart_fix_kind_priority.dart';
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import 'package:analyzer/analysis_rule/analysis_rule.dart';
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import 'package:analyzer/analysis_rule/rule_context.dart';
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import 'package:analyzer/analysis_rule/rule_visitor_registry.dart';
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import 'package:analyzer/dart/ast/ast.dart';
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import 'package:analyzer/dart/ast/visitor.dart';
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import 'package:analyzer/error/error.dart';
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import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
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import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
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import 'package:analyzer_plugin/utilities/range_factory.dart';
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import 'package:leancode_lint/src/type_checker.dart';
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class PreferEquatableMixin extends AnalysisRule {
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PreferEquatableMixin()
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: super(name: code.lowerCaseName, description: code.problemMessage);
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static const code = LintCode(
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'prefer_equatable_mixin',
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'The class {0} should mix in EquatableMixin instead of extending Equatable.',
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correctionMessage: 'Replace with a mixin.',
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severity: .WARNING,
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);
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@override
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LintCode get diagnosticCode => code;
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@override
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void registerNodeProcessors(
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RuleVisitorRegistry registry,
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RuleContext context,
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) {
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registry.addClassDeclaration(this, _Visitor(this, context));
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}
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}
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class _Visitor extends SimpleAstVisitor<void> {
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_Visitor(this.rule, this.context);
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final AnalysisRule rule;
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final RuleContext context;
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static const equatable = TypeChecker.fromName(
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'Equatable',
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packageName: 'equatable',
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);
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static const equatableMixin = TypeChecker.fromName(
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'EquatableMixin',
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packageName: 'equatable',
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);
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@override
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void visitClassDeclaration(ClassDeclaration node) {
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final extendsClause = node.extendsClause;
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if (extendsClause == null) {
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return;
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}
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final superType = extendsClause.superclass.type;
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final isEquatable = superType != null && equatable.isExactlyType(superType);
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final isEquatableMixin =
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node.withClause?.mixinTypes
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.map((mixin) => mixin.type)
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.nonNulls
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.any(equatableMixin.isExactlyType) ??
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false;
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if (isEquatable && !isEquatableMixin) {
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rule.reportAtNode(
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extendsClause.superclass,
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arguments: [node.namePart.typeName.lexeme],
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);
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}
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}
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}
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class ConvertToEquatableMixin extends ResolvedCorrectionProducer {
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ConvertToEquatableMixin({required super.context});
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@override
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FixKind? get fixKind => const FixKind(
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'leancode_lint.fix.convertToEquatableMixin',
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DartFixKindPriority.standard,
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'Convert to EquatableMixin',
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);
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@override
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CorrectionApplicability get applicability => .automatically;
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@override
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Future<void> compute(ChangeBuilder builder) async {
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final classDeclaration = node.thisOrAncestorOfType<ClassDeclaration>()!;
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final extendsClause = classDeclaration.extendsClause!;
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final withClause = classDeclaration.withClause;
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await builder.addDartFileEdit(file, (builder) {
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if (withClause != null) {
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builder
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..addSimpleReplacement(
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range.startStart(extendsClause, withClause),
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'',
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)
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..addSimpleInsertion(
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withClause.mixinTypes.first.offset,
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'EquatableMixin, ',
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);
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} else {
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builder.addSimpleReplacement(
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extendsClause.sourceRange,
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'with EquatableMixin',
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);
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}
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});
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}
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}

‎packages/leancode_lint/test/mock_libraries.dart‎

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import 'package:analyzer_testing/analysis_rule/analysis_rule.dart';
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part 'mock_libraries/bloc.dart';
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part 'mock_libraries/equatable.dart';
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part 'mock_libraries/flutter.dart';
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part 'mock_libraries/flutter_bloc.dart';
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part 'mock_libraries/flutter_hooks.dart';

‎packages/leancode_lint/test/mock_libraries/equatable.dart‎

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part of '../mock_libraries.dart';
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mixin MockEquatable on AnalysisRuleTest {
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@override
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void setUp() {
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newPackage('equatable').addFile('lib/equatable.dart', '''
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class Equatable {
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const Equatable();
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List<Object?> get props;
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}
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mixin EquatableMixin {
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List<Object?> get props;
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}
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''');
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super.setUp();
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}
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}

‎packages/leancode_lint/test/test_cases/prefer_equatable_mixin_test.dart‎

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import 'package:analyzer_testing/analysis_rule/analysis_rule.dart';
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import 'package:leancode_lint/src/lints/prefer_equatable_mixin.dart';
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import 'package:test_reflective_loader/test_reflective_loader.dart';
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import '../assert_ranges.dart';
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import '../mock_libraries.dart';
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void main() {
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defineReflectiveSuite(() {
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defineReflectiveTests(PreferEquatableMixinTest);
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});
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}
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@reflectiveTest
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class PreferEquatableMixinTest extends AnalysisRuleTest with MockEquatable {
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@override
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void setUp() {
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rule = PreferEquatableMixin();
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super.setUp();
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}
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Future<void> test_only_directly_extending_equatable() async {
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await assertDiagnosticsInRanges('''
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import 'package:equatable/equatable.dart';
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class MyState extends [!Equatable!] {
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@override
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List<Object?> get props => [];
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}
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class MyState2 extends MyState {
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@override
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List<Object?> get props => [];
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}
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''');
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}
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Future<void> test_mixin_not_flagged() async {
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await assertNoDiagnostics('''
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import 'package:equatable/equatable.dart';
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class MyState3 with EquatableMixin {
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@override
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List<Object?> get props => [];
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}
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''');
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}
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Future<void> test_with_other_mixins() async {
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await assertDiagnosticsInRanges('''
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import 'package:equatable/equatable.dart';
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mixin SomethingElse {}
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class MyState extends [!Equatable!] with SomethingElse {
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@override
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List<Object?> get props => [];
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}
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class MyState2 extends MyState with SomethingElse {
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@override
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List<Object?> get props => [];
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}
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class MyState3 with SomethingElse, EquatableMixin {
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@override
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List<Object?> get props => [];
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}
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''');
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}
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}

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