pkg/nnbd_migration/test/front_end/unit_renderer_test.dart - sdk.git - Git at Google

 // Copyright (c) 2019, 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:nnbd_migration/nnbd_migration.dart';
 import 'package:nnbd_migration/src/front_end/migration_info.dart';
 import 'package:nnbd_migration/src/front_end/path_mapper.dart';
 import 'package:nnbd_migration/src/front_end/unit_renderer.dart';
 import 'package:nnbd_migration/src/front_end/web/file_details.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';

 import 'nnbd_migration_test_base.dart';

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

 @reflectiveTest
 class UnitRendererTest extends NnbdMigrationTestBase {
   /// Render [libraryInfo], using a [MigrationInfo] which knows only about this
   /// library.
   List<FileDetails> renderUnits() {
     var packageRoot = convertPath('/package');
     var migrationInfo =
         MigrationInfo(infos, {}, resourceProvider.pathContext, packageRoot);

     var contents = <FileDetails>[];
     for (var unitInfo in infos!) {
       contents.add(UnitRenderer(unitInfo, migrationInfo,
               PathMapper(resourceProvider), 'AUTH_TOKEN')
           .render());
     }
     return contents;
   }

   void test_conditionFalseInStrongMode() async {
     await buildInfoForSingleTestFile('''
 int f(String s) {
   if (s == null) {
     return 0;
   } else {
     return s.length;
   }
 }
 ''', migratedContent: '''
 int  f(String  s) {
   if (s == null /* == false */) {
     return 0;
   } else {
     return s.length;
   }
 }
 ''', warnOnWeakCode: true);
     var output = renderUnits()[0];
     expect(
         _stripDataAttributes(output.regions!),
         contains(
             '<span class="region informative-region">/* == false */</span>'));
     expect(output.edits.keys,
         contains('1 condition will be false in strong checking mode'));
   }

   void test_conditionTrueInStrongMode() async {
     await buildInfoForSingleTestFile('''
 int f(String s) {
   if (s != null) {
     return s.length;
   } else {
     return 0;
   }
 }
 ''', migratedContent: '''
 int  f(String  s) {
   if (s != null /* == true */) {
     return s.length;
   } else {
     return 0;
   }
 }
 ''', warnOnWeakCode: true);
     var output = renderUnits()[0];
     expect(
         _stripDataAttributes(output.regions!),
         contains(
             '<span class="region informative-region">/* == true */</span>'));
     expect(output.edits.keys,
         contains('1 condition will be true in strong checking mode'));
   }

   Future<void> test_editList_containsCount() async {
     await buildInfoForSingleTestFile('''
 int a = null;
 bool b = a.isEven;
 ''', migratedContent: '''
 int? a = null;
 bool  b = a!.isEven;
 ''');
     var output = renderUnits()[0];
     var editList = output.edits;
     expect(editList, hasLength(2));
   }

   Future<void> test_editList_containsEdits() async {
     await buildInfoForSingleTestFile('''
 int a = null;
 bool b = a.isEven;
 ''', migratedContent: '''
 int? a = null;
 bool  b = a!.isEven;
 ''');
     var output = renderUnits()[0];
     // The null checks are higher priority than the assertions.
     expect(output.edits.keys,
         orderedEquals(['1 null check added', '1 type made nullable']));
     var typesMadeNullable = output.edits['1 type made nullable']!;
     expect(typesMadeNullable, hasLength(1));
     var typeMadeNullable = typesMadeNullable.single;
     expect(typeMadeNullable.line, equals(1));
     expect(typeMadeNullable.offset, equals(3));
     expect(typeMadeNullable.explanation,
         equals("Changed type 'int' to be nullable"));
     var nullChecks = output.edits['1 null check added']!;
     expect(nullChecks, hasLength(1));
     var nullCheck = nullChecks.single;
     expect(nullCheck.line, equals(2));
     expect(nullCheck.offset, equals(26));
     expect(nullCheck.explanation,
         equals('Added a non-null assertion to nullable expression'));
   }

   Future<void> test_editList_countsHintAcceptanceSingly() async {
     await buildInfoForSingleTestFile('int f(int/*?*/ x) => x/*!*/;',
         migratedContent: 'int  f(int/*?*/ x) => x/*!*/;');
     var output = renderUnits()[0];
     expect(
         output.edits.keys,
         unorderedEquals([
           '1 null check hint converted to null check',
           '1 nullability hint converted to ?'
         ]));
   }

   Future<void> test_editList_countsHintAcceptanceSingly_late() async {
     await buildInfoForSingleTestFile('/*late*/ int x = 0;',
         migratedContent: '/*late*/ int  x = 0;');
     var output = renderUnits()[0];
     expect(output.edits.keys,
         unorderedEquals(['1 late hint converted to late keyword']));
   }

   Future<void> test_editList_countsHintAcceptanceSingly_lateFinal() async {
     await buildInfoForSingleTestFile('/*late final*/ int x = 0;',
         migratedContent: '/*late final*/ int  x = 0;');
     var output = renderUnits()[0];
     expect(
         output.edits.keys,
         unorderedEquals(
             ['1 late final hint converted to late and final keywords']));
   }

   Future<void> test_editList_countsWhereOrNullSingly() async {
     await buildInfoForSingleTestFile(
         '''
 import 'package:collection/collection.dart';

 int firstEven(Iterable<int> x)
     => x.firstWhere((x) => x.isEven, orElse: () => null);
 ''',
         removeViaComments: false,
         migratedContent: '''
 import 'package:collection/collection.dart';

 int? firstEven(Iterable<int >  x)
     => x.firstWherefirstWhereOrNull((x) => x.isEven, orElse: () => null);
 ''');
     var output = renderUnits()[0];
     expect(output.edits.keys,
         unorderedEquals(['1 method name changed', '1 type made nullable']));
   }

   Future<void> test_editList_pluralHeader() async {
     await buildInfoForSingleTestFile('''
 int a = null;
 int b = null;
 ''', migratedContent: '''
 int? a = null;
 int? b = null;
 ''');
     var output = renderUnits()[0];
     expect(output.edits.keys.toList(), ['2 types made nullable']);
   }

   Future<void> test_handle_large_deleted_region_near_top_of_file() async {
     await buildInfoForSingleTestFile('''
 class C {
   int hash(Iterable<int> elements) {
     if (elements == null) {
       return null.hashCode;
     }
     return 0;
   }
 }

 List<int> x = [null];
 ''', migratedContent: '''
 class C {
   int  hash(Iterable<int >  elements) {
     if (elements == null) {
       return null.hashCode;
     }
     return 0;
   }
 }

 List<int?>  x = [null];
 ''', removeViaComments: false);
     renderUnits();
     // No assertions necessary; we are checking to make sure there is no crash.
   }

   Future<void> test_info_within_deleted_code() async {
     await buildInfoForSingleTestFile('''
 class C {
   int hash(Iterable<int> elements) {
     if (elements == null) {
       return null.hashCode;
     }
     return 0;
   }
 }

 List<int> x = [null];
 ''', migratedContent: '''
 class C {
   int  hash(Iterable<int >  elements) {
     if (elements == null) {
       return null.hashCode;
     }
     return 0;
   }
 }

 List<int?>  x = [null];
 ''', removeViaComments: false);
     var output = renderUnits()[0];
     // Strip out URLs and span IDs; they're not being tested here.
     var navContent = output.navigationContent!
         .replaceAll(RegExp('href="[^"]*"'), 'href="..."')
         .replaceAll(RegExp('id="[^"]*"'), 'id="..."');
     expect(navContent, '''
 class <span id="...">C</span> {
   <a href="..." class="nav-link">int</a>  <span id="...">hash</span>(<a href="..." class="nav-link">Iterable</a>&lt;<a href="..." class="nav-link">int</a> &gt;  <span id="...">elements</span>) {
     if (<a href="..." class="nav-link">elements</a> <a href="..." class="nav-link">==</a> null) {
       return null.<a href="..." class="nav-link">hashCode</a>;
     }
     return 0;
   }
 }

 <a href="..." class="nav-link">List</a>&lt;<a href="..." class="nav-link">int</a>?&gt;  <span id="...">x</span> = [null];
 ''');
   }

   Future<void> test_inserted_lines() async {
     await buildInfoForSingleTestFile('''
 int f(List<int> values)
     => values.firstWhere((i) => i.isEven, orElse: () => null);
 ''', migratedContent: '''
 import 'package:collection/collection.dart' show IterableExtension;

 int? f(List<int >  values)
     => values.firstWherefirstWhereOrNull((i) => i.isEven/* , orElse: () => null */);
 ''');
     var output = renderUnits()[0];
     var regions = output.regions!;
     // We're not testing the correctness of the data path, so drop it.
     regions = regions.replaceAll(RegExp(' data-path="[^"]*"'), '');
     // Split the output into table rows.
     var rows = regions.split(RegExp('(?=<tr)'));
     // The table should begin with an added region for the added import; since
     // adding the import involves adding 2 lines, the second and third lines
     // should have a line number of "(new)", and then lines should resume
     // counting at 2 after that.
     expect(rows[0], '<table><tbody>');
     expect(
         rows[1],
         '<tr><td class="line-no">1</td>'
         '<td class="line-1">'
         '<span class="region added-region" data-offset="0" data-line="1">'
         "import 'package:collection/collection.dart' show IterableExtension;"
         '</span></td></tr>');
     expect(rows[2], '<tr><td class="line-no">(new)</td><td></td></tr>');
     expect(rows[3], startsWith('<tr><td class="line-no">(new)</td><td>int'));
     expect(rows[4],
         startsWith('<tr><td class="line-no">2</td><td class="line-2">'));
   }

   void test_kindPriorityOrder() {
     var nonDisplayedKinds = NullabilityFixKind.values.toSet();
     for (var kind in UnitRenderer.kindPriorityOrder) {
       expect(nonDisplayedKinds.remove(kind), isTrue);
     }
     // The only kinds that should not be displayed are those associated with a
     // place where nothing interesting occurred.
     expect(nonDisplayedKinds, {
       NullabilityFixKind.typeNotMadeNullable,
       NullabilityFixKind.typeNotMadeNullableDueToHint
     });
   }

   Future<void> test_method_name_change() async {
     addPackageFile('collection', 'collection.dart', '');
     await buildInfoForSingleTestFile(
         '''
 import 'package:collection/collection.dart';

 int f(List<int> values)
     => values.firstWhere((i) => i.isEven, orElse: () => null);
 ''',
         removeViaComments: false,
         migratedContent: '''
 import 'package:collection/collection.dart';

 int? f(List<int >  values)
     => values.firstWherefirstWhereOrNull((i) => i.isEven, orElse: () => null);
 ''');
     var output = renderUnits()[0];
     var regions = output.regions!;
     // We aren't testing data-offset or data-line behaviors.
     regions = regions.replaceAll(RegExp(' data-offset="[^"]*"'), '');
     regions = regions.replaceAll(RegExp(' data-line="[^"]*"'), '');
     expect(
         regions,
         contains('<span class="region removed-region">firstWhere</span>'
             '<span class="region added-region">firstWhereOrNull</span>('));
   }

   Future<void> test_navContentContainsEscapedHtml() async {
     await buildInfoForSingleTestFile('List<String> a = null;',
         migratedContent: 'List<String >? a = null;');
     var output = renderUnits()[0];
     // Strip out URLs which will change; not being tested here.
     var navContent = output.navigationContent!
         .replaceAll(RegExp('href=".*?"'), 'href="..."');
     expect(
         navContent,
         contains(r'<a href="..." class="nav-link">List</a>'
             r'&lt;<a href="..." class="nav-link">String</a> &gt;? '
             r'<span id="o13">a</span> = null;'));
   }

   void test_nullAwarenessUnnecessaryInStrongMode() async {
     await buildInfoForSingleTestFile('''
 int f(String s) => s?.length;
 ''', migratedContent: '''
 int  f(String  s) => s?.length;
 ''', warnOnWeakCode: true);
     var output = renderUnits()[0];
     expect(_stripDataAttributes(output.regions!),
         contains('s<span class="region informative-region">?</span>.length'));
     expect(
         output.edits.keys,
         contains(
             '1 null-aware access will be unnecessary in strong checking mode'));
   }

   Future<void> test_outputContains_addedType() async {
     await buildInfoForSingleTestFile('''
 void f() {
   final a = <List<int>>[];
   a.add([null]);
 }
 ''', migratedContent: '''
 void f() {
   final List<List<int?>> a = <List<int > >[];
   a.add([null]);
 }
 ''');
     var output = renderUnits()[0];
     var regions = _stripDataAttributes(output.regions!);
     expect(
         regions,
         contains('final '
             '<span class="region added-region">List&lt;List&lt;int?&gt;&gt;</span>'
             ' a = &lt;List&lt;int'
             '<span class="region informative-region"> </span>'
             '&gt;'
             '<span class="region informative-region"> </span>'
             '&gt;[];'));
   }

   Future<void> test_outputContains_replacedVar() async {
     await buildInfoForSingleTestFile('''
 void f() {
   var a = <List<int>>[];
   a.add([null]);
 }
 ''', migratedContent: '''
 void f() {
   varList<List<int?>> a = <List<int > >[];
   a.add([null]);
 }
 ''');
     var output = renderUnits()[0];
     var regions = _stripDataAttributes(output.regions!);
     expect(
         regions,
         contains('<span class="region removed-region">var</span>'
             '<span class="region added-region">List&lt;List&lt;int?&gt;&gt;</span>'
             ' a = &lt;List&lt;int'
             '<span class="region informative-region"> </span>'
             '&gt;'
             '<span class="region informative-region"> </span>'
             '&gt;[];'));
   }

   Future<void> test_outputContainsModifiedAndUnmodifiedRegions() async {
     await buildInfoForSingleTestFile('int a = null;',
         migratedContent: 'int? a = null;');
     var output = renderUnits()[0];
     var regions = _stripDataAttributes(output.regions!);
     expect(regions,
         contains('int<span class="region added-region">?</span> a = null;'));
   }

   Future<void> test_project_with_parts() async {
     // In this test, we migrate a library and its part file.  Both files require
     // addition of a `?`, but at different offsets.  We make sure the `?`s get
     // added at the correct locations in each file.
     var files = {
       convertPath('$projectPath/lib/a.dart'): '''
 part 'b.dart';

 int f() => null;
 ''',
       convertPath('$projectPath/lib/b.dart'): '''
 part of 'a.dart';

 int g() => null;
 ''',
     };
     await buildInfoForTestFiles(files, includedRoot: projectPath);
     var output = renderUnits();
     expect(output[0].sourceCode, contains('int?'));
     expect(output[1].sourceCode, contains('int?'));
   }

   Future<void> test_reference_to_sdk_file_with_parts() async {
     await buildInfoForSingleTestFile('''
 import 'dart:async';
 Future<int> f(Future<int> x) {
   return x.whenComplete(() {});
 }
 ''', migratedContent: '''
 import 'dart:async';
 Future<int >  f(Future<int >  x) {
   return x.whenComplete(() {});
 }
 ''');
     renderUnits();
     // No assertions; we're just making sure there's no crash.
   }

   Future<void> test_regionsContainsEscapedHtml_ampersand() async {
     await buildInfoForSingleTestFile('bool a = true && false;',
         migratedContent: 'bool  a = true && false;');
     var output = renderUnits()[0];
     expect(
         output.regions,
         contains('bool<span class="region informative-region" data-offset="4" '
             'data-line="1"> </span> a = true &amp;&amp; false;'));
   }

   Future<void> test_regionsContainsEscapedHtml_betweenRegions() async {
     await buildInfoForSingleTestFile('List<String> a = null;',
         migratedContent: 'List<String >? a = null;');
     var output = renderUnits()[0];
     var regions = _stripDataAttributes(output.regions!);
     expect(
         regions,
         contains(
             'List&lt;String<span class="region informative-region"> </span>&gt;'
             '<span class="region added-region">?</span> a = null;'));
   }

   Future<void> test_regionsContainsEscapedHtml_region() async {
     await buildInfoForSingleTestFile('f(List<String> a) => a.join(",");',
         migratedContent: 'f(List<String >  a) => a.join(",");');
     var output = renderUnits()[0];
     var regions = _stripDataAttributes(output.regions!);
     expect(
         regions,
         contains(
             'List&lt;String<span class="region informative-region"> </span>'
             '&gt;<span class="region informative-region"> </span>'));
   }

   UnitInfo unit(String path, String content,
       {required List<RegionInfo> regions}) {
     return UnitInfo(convertPath(path))
       ..content = content
       ..regions.addAll(regions);
   }

   /// Strip out data attributes which are not being tested here.
   String _stripDataAttributes(String html) =>
       html.replaceAll(RegExp(' data-[^=]+="[^"]+"'), '');
 }
	// Copyright (c) 2019, 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:nnbd_migration/nnbd_migration.dart';
	import 'package:nnbd_migration/src/front_end/migration_info.dart';
	import 'package:nnbd_migration/src/front_end/path_mapper.dart';
	import 'package:nnbd_migration/src/front_end/unit_renderer.dart';
	import 'package:nnbd_migration/src/front_end/web/file_details.dart';
	import 'package:test/test.dart';
	import 'package:test_reflective_loader/test_reflective_loader.dart';

	import 'nnbd_migration_test_base.dart';

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

	@reflectiveTest
	class UnitRendererTest extends NnbdMigrationTestBase {
	/// Render [libraryInfo], using a [MigrationInfo] which knows only about this
	/// library.
	List<FileDetails> renderUnits() {
	var packageRoot = convertPath('/package');
	var migrationInfo =
	MigrationInfo(infos, {}, resourceProvider.pathContext, packageRoot);

	var contents = <FileDetails>[];
	for (var unitInfo in infos!) {
	contents.add(UnitRenderer(unitInfo, migrationInfo,
	PathMapper(resourceProvider), 'AUTH_TOKEN')
	.render());
	}
	return contents;
	}

	void test_conditionFalseInStrongMode() async {
	await buildInfoForSingleTestFile('''
	int f(String s) {
	if (s == null) {
	return 0;
	} else {
	return s.length;
	}
	}
	''', migratedContent: '''
	int f(String s) {
	if (s == null /* == false */) {
	return 0;
	} else {
	return s.length;
	}
	}
	''', warnOnWeakCode: true);
	var output = renderUnits()[0];
	expect(
	_stripDataAttributes(output.regions!),
	contains(
	'<span class="region informative-region">/* == false */</span>'));
	expect(output.edits.keys,
	contains('1 condition will be false in strong checking mode'));
	}

	void test_conditionTrueInStrongMode() async {
	await buildInfoForSingleTestFile('''
	int f(String s) {
	if (s != null) {
	return s.length;
	} else {
	return 0;
	}
	}
	''', migratedContent: '''
	int f(String s) {
	if (s != null /* == true */) {
	return s.length;
	} else {
	return 0;
	}
	}
	''', warnOnWeakCode: true);
	var output = renderUnits()[0];
	expect(
	_stripDataAttributes(output.regions!),
	contains(
	'<span class="region informative-region">/* == true */</span>'));
	expect(output.edits.keys,
	contains('1 condition will be true in strong checking mode'));
	}

	Future<void> test_editList_containsCount() async {
	await buildInfoForSingleTestFile('''
	int a = null;
	bool b = a.isEven;
	''', migratedContent: '''
	int? a = null;
	bool b = a!.isEven;
	''');
	var output = renderUnits()[0];
	var editList = output.edits;
	expect(editList, hasLength(2));
	}

	Future<void> test_editList_containsEdits() async {
	await buildInfoForSingleTestFile('''
	int a = null;
	bool b = a.isEven;
	''', migratedContent: '''
	int? a = null;
	bool b = a!.isEven;
	''');
	var output = renderUnits()[0];
	// The null checks are higher priority than the assertions.
	expect(output.edits.keys,
	orderedEquals(['1 null check added', '1 type made nullable']));
	var typesMadeNullable = output.edits['1 type made nullable']!;
	expect(typesMadeNullable, hasLength(1));
	var typeMadeNullable = typesMadeNullable.single;
	expect(typeMadeNullable.line, equals(1));
	expect(typeMadeNullable.offset, equals(3));
	expect(typeMadeNullable.explanation,
	equals("Changed type 'int' to be nullable"));
	var nullChecks = output.edits['1 null check added']!;
	expect(nullChecks, hasLength(1));
	var nullCheck = nullChecks.single;
	expect(nullCheck.line, equals(2));
	expect(nullCheck.offset, equals(26));
	expect(nullCheck.explanation,
	equals('Added a non-null assertion to nullable expression'));
	}

	Future<void> test_editList_countsHintAcceptanceSingly() async {
	await buildInfoForSingleTestFile('int f(int/?/ x) => x/!/;',
	migratedContent: 'int f(int/?/ x) => x/!/;');
	var output = renderUnits()[0];
	expect(
	output.edits.keys,
	unorderedEquals([
	'1 null check hint converted to null check',
	'1 nullability hint converted to ?'
	]));
	}

	Future<void> test_editList_countsHintAcceptanceSingly_late() async {
	await buildInfoForSingleTestFile('/late/ int x = 0;',
	migratedContent: '/late/ int x = 0;');
	var output = renderUnits()[0];
	expect(output.edits.keys,
	unorderedEquals(['1 late hint converted to late keyword']));
	}

	Future<void> test_editList_countsHintAcceptanceSingly_lateFinal() async {
	await buildInfoForSingleTestFile('/late final/ int x = 0;',
	migratedContent: '/late final/ int x = 0;');
	var output = renderUnits()[0];
	expect(
	output.edits.keys,
	unorderedEquals(
	['1 late final hint converted to late and final keywords']));
	}

	Future<void> test_editList_countsWhereOrNullSingly() async {
	await buildInfoForSingleTestFile(
	'''
	import 'package:collection/collection.dart';

	int firstEven(Iterable<int> x)
	=> x.firstWhere((x) => x.isEven, orElse: () => null);
	''',
	removeViaComments: false,
	migratedContent: '''
	import 'package:collection/collection.dart';

	int? firstEven(Iterable<int > x)
	=> x.firstWherefirstWhereOrNull((x) => x.isEven, orElse: () => null);
	''');
	var output = renderUnits()[0];
	expect(output.edits.keys,
	unorderedEquals(['1 method name changed', '1 type made nullable']));
	}

	Future<void> test_editList_pluralHeader() async {
	await buildInfoForSingleTestFile('''
	int a = null;
	int b = null;
	''', migratedContent: '''
	int? a = null;
	int? b = null;
	''');
	var output = renderUnits()[0];
	expect(output.edits.keys.toList(), ['2 types made nullable']);
	}

	Future<void> test_handle_large_deleted_region_near_top_of_file() async {
	await buildInfoForSingleTestFile('''
	class C {
	int hash(Iterable<int> elements) {
	if (elements == null) {
	return null.hashCode;
	}
	return 0;
	}
	}

	List<int> x = [null];
	''', migratedContent: '''
	class C {
	int hash(Iterable<int > elements) {
	if (elements == null) {
	return null.hashCode;
	}
	return 0;
	}
	}

	List<int?> x = [null];
	''', removeViaComments: false);
	renderUnits();
	// No assertions necessary; we are checking to make sure there is no crash.
	}

	Future<void> test_info_within_deleted_code() async {
	await buildInfoForSingleTestFile('''
	class C {
	int hash(Iterable<int> elements) {
	if (elements == null) {
	return null.hashCode;
	}
	return 0;
	}
	}

	List<int> x = [null];
	''', migratedContent: '''
	class C {
	int hash(Iterable<int > elements) {
	if (elements == null) {
	return null.hashCode;
	}
	return 0;
	}
	}

	List<int?> x = [null];
	''', removeViaComments: false);
	var output = renderUnits()[0];
	// Strip out URLs and span IDs; they're not being tested here.
	var navContent = output.navigationContent!
	.replaceAll(RegExp('href="[^"]*"'), 'href="..."')
	.replaceAll(RegExp('id="[^"]*"'), 'id="..."');
	expect(navContent, '''
	class <span id="...">C</span> {
	<a href="..." class="nav-link">int</a> <span id="...">hash</span>(<a href="..." class="nav-link">Iterable</a><<a href="..." class="nav-link">int</a> > <span id="...">elements</span>) {
	if (<a href="..." class="nav-link">elements</a> <a href="..." class="nav-link">==</a> null) {
	return null.<a href="..." class="nav-link">hashCode</a>;
	}
	return 0;
	}
	}

	<a href="..." class="nav-link">List</a><<a href="..." class="nav-link">int</a>?> <span id="...">x</span> = [null];
	''');
	}

	Future<void> test_inserted_lines() async {
	await buildInfoForSingleTestFile('''
	int f(List<int> values)
	=> values.firstWhere((i) => i.isEven, orElse: () => null);
	''', migratedContent: '''
	import 'package:collection/collection.dart' show IterableExtension;

	int? f(List<int > values)
	=> values.firstWherefirstWhereOrNull((i) => i.isEven/* , orElse: () => null */);
	''');
	var output = renderUnits()[0];
	var regions = output.regions!;
	// We're not testing the correctness of the data path, so drop it.
	regions = regions.replaceAll(RegExp(' data-path="[^"]*"'), '');
	// Split the output into table rows.
	var rows = regions.split(RegExp('(?=<tr)'));
	// The table should begin with an added region for the added import; since
	// adding the import involves adding 2 lines, the second and third lines
	// should have a line number of "(new)", and then lines should resume
	// counting at 2 after that.
	expect(rows[0], '<table><tbody>');
	expect(
	rows[1],
	'<tr><td class="line-no">1</td>'
	'<td class="line-1">'
	'<span class="region added-region" data-offset="0" data-line="1">'
	"import 'package:collection/collection.dart' show IterableExtension;"
	'</span></td></tr>');
	expect(rows[2], '<tr><td class="line-no">(new)</td><td></td></tr>');
	expect(rows[3], startsWith('<tr><td class="line-no">(new)</td><td>int'));
	expect(rows[4],
	startsWith('<tr><td class="line-no">2</td><td class="line-2">'));
	}

	void test_kindPriorityOrder() {
	var nonDisplayedKinds = NullabilityFixKind.values.toSet();
	for (var kind in UnitRenderer.kindPriorityOrder) {
	expect(nonDisplayedKinds.remove(kind), isTrue);
	}
	// The only kinds that should not be displayed are those associated with a
	// place where nothing interesting occurred.
	expect(nonDisplayedKinds, {
	NullabilityFixKind.typeNotMadeNullable,
	NullabilityFixKind.typeNotMadeNullableDueToHint
	});
	}

	Future<void> test_method_name_change() async {
	addPackageFile('collection', 'collection.dart', '');
	await buildInfoForSingleTestFile(
	'''
	import 'package:collection/collection.dart';

	int f(List<int> values)
	=> values.firstWhere((i) => i.isEven, orElse: () => null);
	''',
	removeViaComments: false,
	migratedContent: '''
	import 'package:collection/collection.dart';

	int? f(List<int > values)
	=> values.firstWherefirstWhereOrNull((i) => i.isEven, orElse: () => null);
	''');
	var output = renderUnits()[0];
	var regions = output.regions!;
	// We aren't testing data-offset or data-line behaviors.
	regions = regions.replaceAll(RegExp(' data-offset="[^"]*"'), '');
	regions = regions.replaceAll(RegExp(' data-line="[^"]*"'), '');
	expect(
	regions,
	contains('<span class="region removed-region">firstWhere</span>'
	'<span class="region added-region">firstWhereOrNull</span>('));
	}

	Future<void> test_navContentContainsEscapedHtml() async {
	await buildInfoForSingleTestFile('List<String> a = null;',
	migratedContent: 'List<String >? a = null;');
	var output = renderUnits()[0];
	// Strip out URLs which will change; not being tested here.
	var navContent = output.navigationContent!
	.replaceAll(RegExp('href=".*?"'), 'href="..."');
	expect(
	navContent,
	contains(r'<a href="..." class="nav-link">List</a>'
	r'<<a href="..." class="nav-link">String</a> >? '
	r'<span id="o13">a</span> = null;'));
	}

	void test_nullAwarenessUnnecessaryInStrongMode() async {
	await buildInfoForSingleTestFile('''
	int f(String s) => s?.length;
	''', migratedContent: '''
	int f(String s) => s?.length;
	''', warnOnWeakCode: true);
	var output = renderUnits()[0];
	expect(_stripDataAttributes(output.regions!),
	contains('s<span class="region informative-region">?</span>.length'));
	expect(
	output.edits.keys,
	contains(
	'1 null-aware access will be unnecessary in strong checking mode'));
	}

	Future<void> test_outputContains_addedType() async {
	await buildInfoForSingleTestFile('''
	void f() {
	final a = <List<int>>[];
	a.add([null]);
	}
	''', migratedContent: '''
	void f() {
	final List<List<int?>> a = <List<int > >[];
	a.add([null]);
	}
	''');
	var output = renderUnits()[0];
	var regions = _stripDataAttributes(output.regions!);
	expect(
	regions,
	contains('final '
	'<span class="region added-region">List<List<int?>></span>'
	' a = <List<int'
	'<span class="region informative-region"> </span>'
	'>'
	'<span class="region informative-region"> </span>'
	'>[];'));
	}

	Future<void> test_outputContains_replacedVar() async {
	await buildInfoForSingleTestFile('''
	void f() {
	var a = <List<int>>[];
	a.add([null]);
	}
	''', migratedContent: '''
	void f() {
	varList<List<int?>> a = <List<int > >[];
	a.add([null]);
	}
	''');
	var output = renderUnits()[0];
	var regions = _stripDataAttributes(output.regions!);
	expect(
	regions,
	contains('<span class="region removed-region">var</span>'
	'<span class="region added-region">List<List<int?>></span>'
	' a = <List<int'
	'<span class="region informative-region"> </span>'
	'>'
	'<span class="region informative-region"> </span>'
	'>[];'));
	}

	Future<void> test_outputContainsModifiedAndUnmodifiedRegions() async {
	await buildInfoForSingleTestFile('int a = null;',
	migratedContent: 'int? a = null;');
	var output = renderUnits()[0];
	var regions = _stripDataAttributes(output.regions!);
	expect(regions,
	contains('int<span class="region added-region">?</span> a = null;'));
	}

	Future<void> test_project_with_parts() async {
	// In this test, we migrate a library and its part file. Both files require
	// addition of a `?`, but at different offsets. We make sure the `?`s get
	// added at the correct locations in each file.
	var files = {
	convertPath('$projectPath/lib/a.dart'): '''
	part 'b.dart';

	int f() => null;
	''',
	convertPath('$projectPath/lib/b.dart'): '''
	part of 'a.dart';

	int g() => null;
	''',
	};
	await buildInfoForTestFiles(files, includedRoot: projectPath);
	var output = renderUnits();
	expect(output[0].sourceCode, contains('int?'));
	expect(output[1].sourceCode, contains('int?'));
	}

	Future<void> test_reference_to_sdk_file_with_parts() async {
	await buildInfoForSingleTestFile('''
	import 'dart:async';
	Future<int> f(Future<int> x) {
	return x.whenComplete(() {});
	}
	''', migratedContent: '''
	import 'dart:async';
	Future<int > f(Future<int > x) {
	return x.whenComplete(() {});
	}
	''');
	renderUnits();
	// No assertions; we're just making sure there's no crash.
	}

	Future<void> test_regionsContainsEscapedHtml_ampersand() async {
	await buildInfoForSingleTestFile('bool a = true && false;',
	migratedContent: 'bool a = true && false;');
	var output = renderUnits()[0];
	expect(
	output.regions,
	contains('bool<span class="region informative-region" data-offset="4" '
	'data-line="1"> </span> a = true && false;'));
	}

	Future<void> test_regionsContainsEscapedHtml_betweenRegions() async {
	await buildInfoForSingleTestFile('List<String> a = null;',
	migratedContent: 'List<String >? a = null;');
	var output = renderUnits()[0];
	var regions = _stripDataAttributes(output.regions!);
	expect(
	regions,
	contains(
	'List<String<span class="region informative-region"> </span>>'
	'<span class="region added-region">?</span> a = null;'));
	}

	Future<void> test_regionsContainsEscapedHtml_region() async {
	await buildInfoForSingleTestFile('f(List<String> a) => a.join(",");',
	migratedContent: 'f(List<String > a) => a.join(",");');
	var output = renderUnits()[0];
	var regions = _stripDataAttributes(output.regions!);
	expect(
	regions,
	contains(
	'List<String<span class="region informative-region"> </span>'
	'><span class="region informative-region"> </span>'));
	}

	UnitInfo unit(String path, String content,
	{required List<RegionInfo> regions}) {
	return UnitInfo(convertPath(path))
	..content = content
	..regions.addAll(regions);
	}

	/// Strip out data attributes which are not being tested here.
	String _stripDataAttributes(String html) =>
	html.replaceAll(RegExp(' data-[^=]+="[^"]+"'), '');
	}