_fe_analyzer_shared/lib/src/exhaustiveness/test_helper.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 'exhaustive.dart';
import 'key.dart';
import 'space.dart';
import 'static_type.dart';

/// Tags used for id-testing of exhaustiveness.
class Tags {
  static const String error = 'error';
  static const String scrutineeType = 'type';
  static const String scrutineeFields = 'fields';
  static const String space = 'space';
  static const String subtypes = 'subtypes';
  static const String expandedSubtypes = 'expandedSubtypes';
}

/// Returns a textual representation for [space] used for testing.
String spacesToText(Space space) {
  String text = space.toString();
  if (text.startsWith('[') && text.endsWith(']')) {
    // Avoid list-like syntax which collides with the [Features] encoding.
    return '<$text>';
  }
  return text;
}

/// Returns a textual representation for [fields] used for testing.
String fieldsToText(StaticType type, ObjectFieldLookup objectFieldLookup,
    Set<Key> fieldsOfInterest) {
  List<Key> sortedNames = fieldsOfInterest.toList()..sort();
  StringBuffer sb = new StringBuffer();
  String comma = '';
  sb.write('{');
  for (Key key in sortedNames) {
    StaticType? fieldType = type.getField(objectFieldLookup, key);
    sb.write(comma);
    sb.write(key.name);
    sb.write(':');
    if (fieldType != null) {
      sb.write(staticTypeToText(fieldType));
    } else {
      sb.write("-");
    }
    comma = ',';
  }
  sb.write('}');
  return sb.toString();
}

/// Returns a textual representation for [type] used for testing.
String staticTypeToText(StaticType type) => type.toString();

/// Returns a textual representation of the subtypes of [type] used for testing.
String? typesToText(Iterable<StaticType> types) {
  if (types.isEmpty) return null;
  // TODO(johnniwinther): Sort types.
  StringBuffer sb = new StringBuffer();
  String comma = '';
  sb.write('{');
  for (StaticType subtype in types) {
    sb.write(comma);
    sb.write(staticTypeToText(subtype));
    comma = ',';
  }
  sb.write('}');
  return sb.toString();
}

String errorToText(ExhaustivenessError error) {
  if (error is NonExhaustiveError) {
    return 'non-exhaustive:${error.witness}';
  } else {
    assert(error is UnreachableCaseError);
    return 'unreachable';
  }
}