make engine tests pass

Author: yjbanov

lib/ui/hash_codes.dart

@@ -15,7 +15,7 @@ const _HashEnd _hashEnd = _HashEnd();
 class _Jenkins {
   static int combine(int hash, Object? o) {
     assert(o is! Iterable);
-    hash = 0x1fffffff & (hash + o!.hashCode);
+    hash = 0x1fffffff & (hash + o.hashCode);
     hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
     return hash ^ (hash >> 6);
   }

lib/ui/hooks.dart

@@ -61,7 +61,7 @@ String? _localeClosure() {
   if (window.locale == null) {
     return null;
   }
-  return window.locale!.toString();
+  return window.locale.toString();
 }
 
 @pragma('vm:entry-point')

lib/ui/painting.dart

@@ -2354,7 +2354,11 @@ class PathMetricIterator implements Iterator<PathMetric> {
   PathMetric get current {
     final PathMetric? currentMetric = _pathMetric;
     if (currentMetric == null) {
-      throw RangeError('No more path metrics.');
+      throw RangeError(
+        'PathMetricIterator is not pointing to a PathMetric. This can happen in two situations:\n'
+        '- The iteration has not started yet. If so, call "moveNext" to start iteration.'
+        '- The iterator ran out of elements. If so, check that "moveNext" returns true prior to calling "current".'
+      );
     }
     return currentMetric;
   }

lib/ui/text.dart

@@ -2021,9 +2021,10 @@ class Paragraph extends NativeFieldWrapperClass2 {
   /// to repeatedly call this. Instead, cache the results.
   List<LineMetrics> computeLineMetrics() {
     final Float64List encoded = _computeLineMetrics();
+    final int count = encoded.length ~/ 9;
     int position = 0;
     final List<LineMetrics> metrics = <LineMetrics>[];
-    for (int index = 0; index < metrics.length; index += 1) {
+    for (int index = 0; index < count; index += 1) {
       metrics.add(LineMetrics(
         hardBreak:      encoded[position++] != 0,
         ascent:         encoded[position++],

testing/dart/image_filter_test.dart

@@ -86,13 +86,6 @@ void main() {
     checkEquality(B, B);
   });
 
-  test('ImageFilter - nulls', () async {
-    final Paint paint = Paint()..imageFilter = ImageFilter.blur(sigmaX: null, sigmaY: null);
-    expect(paint.imageFilter, equals(ImageFilter.blur()));
-
-    expect(() => ImageFilter.matrix(null), throwsNoSuchMethodError);
-  });
-
   void checkBytes(Uint32List bytes, int center, int side, int corner) {
     expect(bytes[0], equals(corner));
     expect(bytes[1], equals(side));

testing/dart/path_test.dart

@@ -115,7 +115,7 @@ void main() {
 
     // basic tests on horizontal line
     final PathMetrics simpleHorizontalMetrics = simpleHorizontalLine.computeMetrics();
-    expect(simpleHorizontalMetrics.iterator.current, isNull);
+    expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);
     expect(simpleHorizontalMetrics.iterator.moveNext(), isTrue);
     expect(simpleHorizontalMetrics.iterator.current, isNotNull);
     expect(simpleHorizontalMetrics.iterator.current.length, equals(10.0));
@@ -128,11 +128,11 @@ void main() {
     expect(posTan.angle, equals(0.0));
 
     expect(simpleHorizontalMetrics.iterator.moveNext(), isFalse);
-    expect(simpleHorizontalMetrics.iterator.current, isNull);
+    expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);
 
     // test with forceClosed
     final PathMetrics simpleMetricsClosed = simpleHorizontalLine.computeMetrics(forceClosed: true);
-    expect(simpleMetricsClosed.iterator.current, isNull);
+    expect(() => simpleHorizontalMetrics.iterator.current, throwsRangeError);
     expect(simpleMetricsClosed.iterator.moveNext(), isTrue);
     expect(simpleMetricsClosed.iterator.current, isNotNull);
     expect(simpleMetricsClosed.iterator.current.length, equals(20.0)); // because we forced close
@@ -163,15 +163,15 @@ void main() {
       ..lineTo(10.0, 15.0);
 
     final PathMetrics multiContourMetric = multiContour.computeMetrics();
-    expect(multiContourMetric.iterator.current, isNull);
+    expect(() => multiContourMetric.iterator.current, throwsRangeError);
     expect(multiContourMetric.iterator.moveNext(), isTrue);
     expect(multiContourMetric.iterator.current, isNotNull);
     expect(multiContourMetric.iterator.current.length, equals(10.0));
     expect(multiContourMetric.iterator.moveNext(), isTrue);
     expect(multiContourMetric.iterator.current, isNotNull);
     expect(multiContourMetric.iterator.current.length, equals(5.0));
     expect(multiContourMetric.iterator.moveNext(), isFalse);
-    expect(multiContourMetric.iterator.current, isNull);
+    expect(() => multiContourMetric.iterator.current, throwsRangeError);
   });
 
   test('PathMetrics can remember lengths and isClosed', () {