Add tests covering cases in issue 16069

tests/html/canvas_pixel_array_type_alias_test.dart

Index: tests/html/canvas_pixel_array_type_alias_test.dart
diff --git a/tests/html/canvas_pixel_array_type_alias_test.dart b/tests/html/canvas_pixel_array_type_alias_test.dart
index 250824d86429d850a26052216f72b2ef5257525f..9323ec08895353de354afca750a0c52af0571c45 100644
--- a/tests/html/canvas_pixel_array_type_alias_test.dart
+++ b/tests/html/canvas_pixel_array_type_alias_test.dart
@@ -1,50 +1,109 @@
+// Copyright (c) 2013, 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
+
 library CanvasTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
+import 'dart:typed_data';
 
 // We have aliased the legacy type CanvasPixelArray with the new type
 // Uint8ClampedArray by mapping the CanvasPixelArray type tag to
 // Uint8ClampedArray.  It is not a perfect match since CanvasPixelArray is
 // missing the ArrayBufferView members.  These should appear to be null.
 
-Object confuseType(x) => [1, x, [x], 's'] [1];
+var inscrutable;
 
 main() {
-  CanvasElement canvas;
-  CanvasRenderingContext2D context;
+
+  inscrutable = (x) => x;
+
   int width = 100;
   int height = 100;
 
-  canvas = new Element.tag('canvas');
-  canvas.width = width;
-  canvas.height = height;
+  CanvasElement canvas = new CanvasElement(width: width, height: height);
   document.body.append(canvas);
 
-  context = canvas.getContext('2d');
+  CanvasRenderingContext2D context = canvas.context2D;
 
   useHtmlConfiguration();
 
-  test('CreateImageData', () {
-    ImageData image = context.createImageData(canvas.width,
-                                              canvas.height);
-    List<int> data = image.data;
-    // It is legal for the dart2js compiler to believe the type of the native
-    // ImageData.data and elides the check, so check the type explicitly:
-    expect(confuseType(data) is List<int>, isTrue,
-        reason: 'canvas array type');
-
-    expect(data, hasLength(40000));
-    checkPixel(data, 0, [0, 0, 0, 0]);
-    checkPixel(data, width * height - 1, [0, 0, 0, 0]);
-
-    data[100] = 200;
-    expect(data[100], equals(200));
+  group('basic', () {
+    test('CreateImageData', () {
+      ImageData image = context.createImageData(canvas.width,
+                                                canvas.height);
+      List<int> data = image.data;
+      // It is legal for the dart2js compiler to believe the type of the native
+      //   ImageData.data and elides the check, so check the type explicitly:
+      expect(inscrutable(data) is List<int>, isTrue,
+          reason: 'canvas array type');
+
+      expect(data, hasLength(40000));
+      checkPixel(data, 0, [0, 0, 0, 0]);
+      checkPixel(data, width * height - 1, [0, 0, 0, 0]);
+
+      data[100] = 200;
+      expect(data[100], equals(200));
+    });
+  });
+
+  group('types1', () {
+    test('isList', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect(inscrutable(data) is List, true);
+    });
+
+    test('isListT_pos', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect(inscrutable(data) is List<int>, true);
+    });
+  });
+
+  group('types2', () {
+    test('isListT_neg', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect(inscrutable(data) is List<String>, false);
+    });
+
+    test('isUint8ClampedList', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect(inscrutable(data) is Uint8ClampedList, true);
+    });
+
+    test('consistent_isUint8ClampedList', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      // Static and dynamic values consistent?  Type inference should be able to
+      // constant-fold 'data is Uint8ClampedList' to 'true'.
+      expect(inscrutable(data) is Uint8ClampedList == data is Uint8ClampedList,
+             isTrue);
+    });
+
+    test('runtimeType', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect(inscrutable(data).runtimeType, Uint8ClampedList);
+    });
+
+    test('consistent_runtimeType', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect(inscrutable(data).runtimeType == data.runtimeType, isTrue);
+    });
+
+    test('runtimeTypeName', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect('${inscrutable(data).runtimeType}', 'Uint8ClampedList');
+    });
+  });
+
+  group('typed_data', () {
+    test('elementSizeInBytes', () {
+      var data = context.createImageData(canvas.width, canvas.height).data;
+      expect(inscrutable(data).elementSizeInBytes, 1);
+    });
   });
 }
 
-void checkPixel(List<int> data, int offset, List<int> rgba)
-{
+void checkPixel(List<int> data, int offset, List<int> rgba) {
   offset *= 4;
   for (var i = 0; i < 4; ++i) {
     expect(rgba[i], equals(data[offset + i]));