Migrate several test files to null safety

test/markdown_processor_test.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 library dartdoc.markdown_processor_test;
 
 import 'package:dartdoc/src/markdown_processor.dart';

test/model_utils_test.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 library dartdoc.model_utils_test;
 
 import 'package:dartdoc/src/model_utils.dart';

test/quiver_test.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 import 'package:dartdoc/src/quiver.dart';
 import 'package:test/test.dart';
 
@@ -30,20 +28,6 @@ void main() {
           [1, 2, 3, -1, -2, -3]);
     });
 
-    test('should throw for null input', () {
-      expect(() => concat(null), throwsNoSuchMethodError);
-    });
-
-    test('should throw if any input is null', () {
-      expect(
-          () => concat([
-                [1, 2],
-                null,
-                [3, 4]
-              ]).toList(),
-          throwsNoSuchMethodError);
-    });
-
     test('should reflectchanges in the inputs', () {
       var a = [1, 2];
       var b = [4, 5];

test/resource_loader_test.dart

@@ -2,22 +2,15 @@
 // 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.
 
-// @dart=2.9
-
 library dartdoc.resource_loader_test;
 
-import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:dartdoc/src/generator/resource_loader.dart';
 import 'package:test/test.dart';
 
 void main() {
   group('Resource Loader', () {
-    ResourceProvider resourceProvider;
-
-    setUp(() {
-      resourceProvider = PhysicalResourceProvider();
-    });
+    var resourceProvider = PhysicalResourceProvider();
 
     test('load from packages', () async {
       var contents = await resourceProvider

test/source_linker_test.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 library dartdoc.source_linker_test;
 
 import 'package:dartdoc/src/dartdoc_options.dart';

test/tool_runner_test.dart

@@ -2,8 +2,6 @@
 // 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.
 
-// @dart=2.9
-
 library dartdoc.model_test;
 
 import 'dart:io';
@@ -21,18 +19,17 @@ final Directory _toolExecutableDir = Directory('testing/tool_executables');
 
 void main() {
   ToolConfiguration toolMap;
-  Directory tempDir;
-  File setupFile;
+  Directory? tempDir;
+  late File setupFile;
 
-  ToolRunner runner;
-  ToolTempFileTracker tracker;
-  ToolErrorCallback errorCallback;
+  late ToolRunner runner;
+  late ToolErrorCallback errorCallback;
   final errors = <String>[];
 
   setUpAll(() async {
-    ProcessResult result;
+    ProcessResult? result;
     tempDir = Directory.systemTemp.createTempSync('tool_runner_test_');
-    var snapshotFile = path.join(tempDir.path, 'drill.snapshot');
+    var snapshotFile = path.join(tempDir!.path, 'drill.snapshot');
     try {
       result = Process.runSync(
           Platform.resolvedExecutable,
@@ -52,7 +49,7 @@ void main() {
       stderr.writeln(result.stderr);
     }
     expect(result?.exitCode, equals(0));
-    setupFile = File(path.join(tempDir.path, 'setup.stamp'));
+    setupFile = File(path.join(tempDir!.path, 'setup.stamp'));
     var nonDartName = Platform.isWindows ? 'non_dart.bat' : 'non_dart.sh';
     var nonDartExecutable =
         path.join(_toolExecutableDir.absolute.path, nonDartName);
@@ -94,13 +91,11 @@ echo:
     runner = ToolRunner(toolMap);
     errorCallback = (String message) => errors.add(message);
   });
+
   tearDownAll(() {
     tempDir?.deleteSync(recursive: true);
-    tracker?.dispose();
     SnapshotCache.instanceFor(pubPackageMetaProvider.resourceProvider)
         .dispose();
-    setupFile = null;
-    tempDir = null;
   });
 
   group('ToolRunner', () {
@@ -110,7 +105,8 @@ echo:
     // This test must come first, to verify that the first run creates
     // a snapshot.
     test('Tool definition includes compile arguments.', () async {
-      DartToolDefinition definition = runner.toolConfiguration.tools['drill'];
+      var definition =
+          runner.toolConfiguration.tools['drill'] as DartToolDefinition;
       expect(definition.compileArgs, equals(['--no-sound-null-safety']));
     });
     test('can invoke a Dart tool, and second run is a snapshot.', () async {

test/utils_test.dart

@@ -2,16 +2,14 @@
 // 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.
 
-// @dart=2.9
-
 library dartdoc.utils_test;
 
 import 'package:dartdoc/src/utils.dart';
 import 'package:test/test.dart';
 
 void main() {
-  String comment;
-  String documentation;
+  late String comment;
+  late String documentation;
 
   // For readability, the multiline strings below have a left margin. This
   // is the length of that left margin.

test/warnings_test.dart

@@ -17,12 +17,11 @@ import 'package:test/test.dart';
 
 void main() {
   ResourceProvider resourceProvider = PhysicalResourceProvider.INSTANCE;
-  Folder tempDir, testPackageOne, testPackageTwo, testPackageThree;
-  File pubspecYamlOne, pubspecYamlTwo, pubspecYamlThree, dartdocYamlThree;
+  Folder testPackageOne, testPackageTwo, testPackageThree;
   DartdocOptionSet optionSet;
 
   setUpAll(() {
-    tempDir = resourceProvider.createSystemTemp('warnings_test');
+    var tempDir = resourceProvider.createSystemTemp('warnings_test');
     testPackageOne = resourceProvider.getFolder(
         resourceProvider.pathContext.join(tempDir.path, 'test_package_one'))
       ..create();
@@ -32,13 +31,13 @@ void main() {
     testPackageThree = resourceProvider.getFolder(
         resourceProvider.pathContext.join(tempDir.path, 'test_package_three'))
       ..create();
-    pubspecYamlOne = resourceProvider.getFile(
+    var pubspecYamlOne = resourceProvider.getFile(
         resourceProvider.pathContext.join(testPackageOne.path, 'pubspec.yaml'));
     pubspecYamlOne.writeAsStringSync('name: test_package_one');
-    pubspecYamlTwo = resourceProvider.getFile(
+    var pubspecYamlTwo = resourceProvider.getFile(
         resourceProvider.pathContext.join(testPackageTwo.path, 'pubspec.yaml'));
     pubspecYamlTwo.writeAsStringSync('name: test_package_two');
-    dartdocYamlThree = resourceProvider.getFile(resourceProvider.pathContext
+    var dartdocYamlThree = resourceProvider.getFile(resourceProvider.pathContext
         .join(testPackageThree.path, 'dartdoc_options.yaml'));
     dartdocYamlThree.writeAsStringSync('''
 dartdoc:
@@ -50,7 +49,7 @@ dartdoc:
   ignore:
     - ambiguous-reexport  
     ''');
-    pubspecYamlThree = resourceProvider.getFile(resourceProvider.pathContext
+    var pubspecYamlThree = resourceProvider.getFile(resourceProvider.pathContext
         .join(testPackageThree.path, 'pubspec.yaml'));
     pubspecYamlThree.writeAsStringSync('name: test_package_three');
   });