Fix WidgetsApp to wrap its contents in a Directionality (#12018)

...rather than only wrapping the children.

Also, improvements to Banner to better support RTL, and mock_canvas to
make debugging things easier.

packages/flutter/lib/src/foundation/print.dart

@@ -104,7 +104,7 @@ enum _WordWrapParseMode { inSpace, inWord, atBreak }
 ///
 /// The default [debugPrint] implementation uses this for its line wrapping.
 Iterable<String> debugWordWrap(String message, int width, { String wrapIndent: '' }) sync* {
-  if (message.length < width || message[0] == '#') {
+  if (message.length < width || message.trimLeft()[0] == '#') {
     yield message;
     return;
   }

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -2293,6 +2293,7 @@ class RenderCustomPaint extends RenderProxyBox {
     int debugPreviousCanvasSaveCount;
     canvas.save();
     assert(() { debugPreviousCanvasSaveCount = canvas.getSaveCount(); return true; });
+    if (offset != Offset.zero)
       canvas.translate(offset.dx, offset.dy);
     painter.paint(canvas, size);
     assert(() {

packages/flutter/lib/src/widgets/app.dart

@@ -296,28 +296,18 @@ class _WidgetsAppState extends State<WidgetsApp> implements WidgetsBindingObserv
 
   @override
   Widget build(BuildContext context) {
-    Widget result = new MediaQuery(
-      data: new MediaQueryData.fromWindow(ui.window),
-      child: new Localizations(
-        locale: widget.locale ?? _locale,
-        delegates: _localizationsDelegates.toList(),
-        child: new Title(
-          title: widget.title,
-          color: widget.color,
-          child: new Navigator(
+    Widget result = new Navigator(
       key: _navigator,
       initialRoute: widget.initialRoute ?? ui.window.defaultRouteName,
       onGenerateRoute: widget.onGenerateRoute,
       onUnknownRoute: widget.onUnknownRoute,
-            observers: widget.navigatorObservers
-          )
-        )
-      )
+      observers: widget.navigatorObservers,
     );
+
     if (widget.textStyle != null) {
       result = new DefaultTextStyle(
         style: widget.textStyle,
-        child: result
+        child: result,
       );
     }
 
@@ -335,7 +325,6 @@ class _WidgetsAppState extends State<WidgetsApp> implements WidgetsBindingObserv
         checkerboardOffscreenLayers: widget.checkerboardOffscreenLayers,
       );
     }
-
     if (performanceOverlay != null) {
       result = new Stack(
         children: <Widget>[
@@ -344,11 +333,13 @@ class _WidgetsAppState extends State<WidgetsApp> implements WidgetsBindingObserv
         ]
       );
     }
+
     if (widget.showSemanticsDebugger) {
       result = new SemanticsDebugger(
         child: result,
       );
     }
+
     assert(() {
       if (widget.debugShowWidgetInspector || WidgetsApp.debugShowWidgetInspectorOverride) {
         result = new WidgetInspector(
@@ -364,7 +355,17 @@ class _WidgetsAppState extends State<WidgetsApp> implements WidgetsBindingObserv
       return true;
     });
 
-    return result;
+    return new MediaQuery(
+      data: new MediaQueryData.fromWindow(ui.window),
+      child: new Localizations(
+        locale: widget.locale ?? _locale,
+        delegates: _localizationsDelegates.toList(),
+        child: new Title(
+          title: widget.title,
+          color: widget.color,
+          child: result,
+        ),
+      ),
+    );
   }
-
 }

packages/flutter/lib/src/widgets/banner.dart

@@ -23,25 +23,30 @@ const TextStyle _kTextStyle = const TextStyle(
 );
 
 /// Where to show a [Banner].
+///
+/// The start and end locations are relative to the ambient [Directionality]
+/// (which can be overridden by [Banner.layoutDirection]).
 enum BannerLocation {
   /// Show the banner in the top-right corner when the ambient [Directionality]
-  /// is [TextDirection.rtl] and in the top-left corner when the ambient
-  /// [Directionality] is [TextDirection.ltr].
+  /// (or [Banner.layoutDirection]) is [TextDirection.rtl] and in the top-left
+  /// corner when the ambient [Directionality] is [TextDirection.ltr].
   topStart,
 
   /// Show the banner in the top-left corner when the ambient [Directionality]
-  /// is [TextDirection.rtl] and in the top-right corner when the ambient
-  /// [Directionality] is [TextDirection.ltr].
+  /// (or [Banner.layoutDirection]) is [TextDirection.rtl] and in the top-right
+  /// corner when the ambient [Directionality] is [TextDirection.ltr].
   topEnd,
 
   /// Show the banner in the bottom-right corner when the ambient
-  /// [Directionality] is [TextDirection.rtl] and in the bottom-left corner when
-  /// the ambient [Directionality] is [TextDirection.ltr].
+  /// [Directionality] (or [Banner.layoutDirection]) is [TextDirection.rtl] and
+  /// in the bottom-left corner when the ambient [Directionality] is
+  /// [TextDirection.ltr].
   bottomStart,
 
   /// Show the banner in the bottom-left corner when the ambient
-  /// [Directionality] is [TextDirection.rtl] and in the bottom-right corner when
-  /// the ambient [Directionality] is [TextDirection.ltr].
+  /// [Directionality] (or [Banner.layoutDirection]) is [TextDirection.rtl] and
+  /// in the bottom-right corner when the ambient [Directionality] is
+  /// [TextDirection.ltr].
   bottomEnd,
 }
 
@@ -49,11 +54,13 @@ enum BannerLocation {
 class BannerPainter extends CustomPainter {
   /// Creates a banner painter.
   ///
-  /// The [message], [textDirection], and [location] arguments must not be null.
+  /// The [message], [textDirection], [location], and [layoutDirection]
+  /// arguments must not be null.
   BannerPainter({
     @required this.message,
     @required this.textDirection,
     @required this.location,
+    @required this.layoutDirection,
     this.color: _kColor,
     this.textStyle: _kTextStyle,
   }) : assert(message != null),
@@ -74,12 +81,21 @@ class BannerPainter extends CustomPainter {
   /// context, the English phrase will be on the right and the Hebrow phrase on
   /// its left.
   ///
-  /// This value is also used to interpret the [location] of the banner.
+  /// See also [layoutDirection], which controls the interpretation of values in
+  /// [location].
   final TextDirection textDirection;
 
   /// Where to show the banner (e.g., the upper right corder).
   final BannerLocation location;
 
+  /// The directionality of the layout.
+  ///
+  /// This value is used to interpret the [location] of the banner.
+  ///
+  /// See also [textDirection], which controls the reading direction of the
+  /// [message].
+  final TextDirection layoutDirection;
+
   /// The color to paint behind the [message].
   ///
   /// Defaults to a dark red.
@@ -136,8 +152,8 @@ class BannerPainter extends CustomPainter {
 
   double _translationX(double width) {
     assert(location != null);
-    assert(textDirection != null);
-    switch (textDirection) {
+    assert(layoutDirection != null);
+    switch (layoutDirection) {
       case TextDirection.rtl:
         switch (location) {
           case BannerLocation.bottomEnd:
@@ -181,8 +197,8 @@ class BannerPainter extends CustomPainter {
 
   double get _rotation {
     assert(location != null);
-    assert(textDirection != null);
-    switch (textDirection) {
+    assert(layoutDirection != null);
+    switch (layoutDirection) {
       case TextDirection.rtl:
         switch (location) {
           case BannerLocation.bottomStart:
@@ -215,7 +231,8 @@ class BannerPainter extends CustomPainter {
 ///
 /// See also:
 ///
-///  * [CheckedModeBanner].
+///  * [CheckedModeBanner], which the [WidgetsApp] widget includes by default in
+///    debug mode, to show a banner that says "SLOW MODE".
 class Banner extends StatelessWidget {
   /// Creates a banner.
   ///
@@ -226,6 +243,7 @@ class Banner extends StatelessWidget {
     @required this.message,
     this.textDirection,
     @required this.location,
+    this.layoutDirection,
     this.color: _kColor,
     this.textStyle: _kTextStyle,
   }) : assert(message != null),
@@ -250,11 +268,24 @@ class Banner extends StatelessWidget {
   /// its left.
   ///
   /// Defaults to the ambient [Directionality], if any.
+  ///
+  /// See also [layoutDirection], which controls the interpretation of the
+  /// [location].
   final TextDirection textDirection;
 
   /// Where to show the banner (e.g., the upper right corder).
   final BannerLocation location;
 
+  /// The directionality of the layout.
+  ///
+  /// This is used to resolve the [location] values.
+  ///
+  /// Defaults to the ambient [Directionality], if any.
+  ///
+  /// See also [textDirection], which controls the reading direction of the
+  /// [message].
+  final TextDirection layoutDirection;
+
   /// The color of the banner.
   final Color color;
 
@@ -268,6 +299,7 @@ class Banner extends StatelessWidget {
         message: message,
         textDirection: textDirection ?? Directionality.of(context),
         location: location,
+        layoutDirection: layoutDirection ?? Directionality.of(context),
         color: color,
         textStyle: textStyle,
       ),
@@ -281,6 +313,7 @@ class Banner extends StatelessWidget {
     description.add(new StringProperty('message', message, showName: false));
     description.add(new EnumProperty<TextDirection>('textDirection', textDirection, defaultValue: null));
     description.add(new EnumProperty<BannerLocation>('location', location));
+    description.add(new EnumProperty<TextDirection>('layoutDirection', layoutDirection, defaultValue: null));
     description.add(new DiagnosticsProperty<Color>('color', color, showName: false));
     textStyle?.debugFillProperties(description, prefix: 'text ');
   }

packages/flutter/test/rendering/mock_canvas.dart

@@ -248,6 +248,13 @@ abstract class PaintPattern {
   void something(PaintPatternPredicate predicate);
 }
 
+class _MismatchedCall {
+  const _MismatchedCall(this.message, this.callIntroduction, this.call) : assert(call != null);
+  final String message;
+  final String callIntroduction;
+  final RecordedInvocation call;
+}
+
 abstract class _TestRecordingCanvasMatcher extends Matcher {
   @override
   bool matches(Object object, Map<dynamic, dynamic> matchState) {
@@ -276,17 +283,16 @@ abstract class _TestRecordingCanvasMatcher extends Matcher {
     final StringBuffer description = new StringBuffer();
     final bool result = _evaluatePredicates(canvas.invocations, description);
     if (!result) {
-      const String indent = '\n            '; // the length of '   Which: ' in spaces, plus two more
       if (canvas.invocations.isNotEmpty)
-        description.write(' The complete display list was:');
-        for (Invocation call in canvas.invocations)
-          description.write('$indent${_describeInvocation(call)}');
+        description.write('The complete display list was:');
+        for (RecordedInvocation call in canvas.invocations)
+          description.write('\n  * $call');
+      matchState[this] = 'did not match the pattern.\n$description';
     }
-    matchState[this] = description.toString();
     return result;
   }
 
-  bool _evaluatePredicates(Iterable<Invocation> calls, StringBuffer description);
+  bool _evaluatePredicates(Iterable<RecordedInvocation> calls, StringBuffer description);
 
   @override
   Description describeMismatch(
@@ -306,10 +312,13 @@ class _TestRecordingCanvasPaintsNothingMatcher extends _TestRecordingCanvasMatch
   }
 
   @override
-  bool _evaluatePredicates(Iterable<Invocation> calls, StringBuffer description) {
+  bool _evaluatePredicates(Iterable<RecordedInvocation> calls, StringBuffer description) {
     if (calls.isEmpty)
       return true;
-    description.write('painted the following.');
+    description.write(
+      'painted something, the first call having the following stack:\n'
+      '${calls.first.stackToString(indent: "  ")}\n'
+    );
     return false;
   }
 }
@@ -409,32 +418,42 @@ class _TestRecordingCanvasPatternMatcher extends _TestRecordingCanvasMatcher imp
   }
 
   @override
-  bool _evaluatePredicates(Iterable<Invocation> calls, StringBuffer description) {
+  bool _evaluatePredicates(Iterable<RecordedInvocation> calls, StringBuffer description) {
     if (calls.isEmpty) {
-      description.write('painted nothing.');
+      description.writeln('It painted nothing.');
       return false;
     }
     if (_predicates.isEmpty) {
-      description.write(
-        'painted something, but you must now add a pattern to the paints matcher '
+      description.writeln(
+        'It painted something, but you must now add a pattern to the paints matcher '
         'in the test to verify that it matches the important parts of the following.'
       );
       return false;
     }
     final Iterator<_PaintPredicate> predicate = _predicates.iterator;
-    final Iterator<Invocation> call = calls.iterator..moveNext();
+    final Iterator<RecordedInvocation> call = calls.iterator..moveNext();
     try {
       while (predicate.moveNext()) {
         if (call.current == null) {
-          throw 'painted less on its canvas than the paint pattern expected. '
+          throw 'It painted less on its canvas than the paint pattern expected. '
                 'The first missing paint call was: ${predicate.current}';
         }
         predicate.current.match(call);
       }
       assert(predicate.current == null);
       // We allow painting more than expected.
+    } on _MismatchedCall catch (data) {
+      description.writeln(data.message);
+      description.writeln(data.callIntroduction);
+      description.writeln(data.call.stackToString(indent: '  '));
+      return false;
     } on String catch (s) {
-      description.write(s);
+      description.writeln(s);
+      if (call.current != null) {
+        description.write('The stack of the offending call was:\n${call.current.stackToString(indent: "  ")}\n');
+      } else {
+        description.write('The stack of the first call was:\n${calls.first.stackToString(indent: "  ")}\n');
+      }
       return false;
     }
     return true;
@@ -442,7 +461,7 @@ class _TestRecordingCanvasPatternMatcher extends _TestRecordingCanvasMatcher imp
 }
 
 abstract class _PaintPredicate {
-  void match(Iterator<Invocation> call);
+  void match(Iterator<RecordedInvocation> call);
 
   @override
   String toString() {
@@ -468,20 +487,24 @@ abstract class _DrawCommandPaintPredicate extends _PaintPredicate {
   String get methodName => _symbolName(symbol);
 
   @override
-  void match(Iterator<Invocation> call) {
+  void match(Iterator<RecordedInvocation> call) {
     int others = 0;
-    final Invocation firstCall = call.current;
-    while (!call.current.isMethod || call.current.memberName != symbol) {
+    final RecordedInvocation firstCall = call.current;
+    while (!call.current.invocation.isMethod || call.current.invocation.memberName != symbol) {
       others += 1;
       if (!call.moveNext())
-        throw 'called $others other method${ others == 1 ? "" : "s" } on the canvas, '
-              'the first of which was ${_describeInvocation(firstCall)}, but did not '
-              'call $methodName at the time where $this was expected.';
+        throw new _MismatchedCall(
+          'It called $others other method${ others == 1 ? "" : "s" } on the canvas, '
+          'the first of which was $firstCall, but did not '
+          'call $methodName at the time where $this was expected.',
+          'The stack for the call to $firstCall was:',
+          firstCall,
+        );
     }
-    final int actualArgumentCount = call.current.positionalArguments.length;
+    final int actualArgumentCount = call.current.invocation.positionalArguments.length;
     if (actualArgumentCount != argumentCount)
-      throw 'called $methodName with $actualArgumentCount argument${actualArgumentCount == 1 ? "" : "s"}; expected $argumentCount.';
-    verifyArguments(call.current.positionalArguments);
+      throw 'It called $methodName with $actualArgumentCount argument${actualArgumentCount == 1 ? "" : "s"}; expected $argumentCount.';
+    verifyArguments(call.current.invocation.positionalArguments);
     call.moveNext();
   }
 
@@ -490,17 +513,17 @@ abstract class _DrawCommandPaintPredicate extends _PaintPredicate {
   void verifyArguments(List<dynamic> arguments) {
     final Paint paintArgument = arguments[paintArgumentIndex];
     if (color != null && paintArgument.color != color)
-      throw 'called $methodName with a paint whose color, ${paintArgument.color}, was not exactly the expected color ($color).';
+      throw 'It called $methodName with a paint whose color, ${paintArgument.color}, was not exactly the expected color ($color).';
     if (strokeWidth != null && paintArgument.strokeWidth != strokeWidth)
-      throw 'called $methodName with a paint whose strokeWidth, ${paintArgument.strokeWidth}, was not exactly the expected strokeWidth ($strokeWidth).';
+      throw 'It called $methodName with a paint whose strokeWidth, ${paintArgument.strokeWidth}, was not exactly the expected strokeWidth ($strokeWidth).';
     if (hasMaskFilter != null && (paintArgument.maskFilter != null) != hasMaskFilter) {
       if (hasMaskFilter)
-        throw 'called $methodName with a paint that did not have a mask filter, despite expecting one.';
+        throw 'It called $methodName with a paint that did not have a mask filter, despite expecting one.';
       else
-        throw 'called $methodName with a paint that did have a mask filter, despite not expecting one.';
+        throw 'It called $methodName with a paint that did have a mask filter, despite not expecting one.';
     }
     if (style != null && paintArgument.style != style)
-      throw 'called $methodName with a paint whose style, ${paintArgument.style}, was not exactly the expected style ($style).';
+      throw 'It called $methodName with a paint whose style, ${paintArgument.style}, was not exactly the expected style ($style).';
   }
 
   @override
@@ -544,7 +567,7 @@ class _OneParameterPaintPredicate<T> extends _DrawCommandPaintPredicate {
     super.verifyArguments(arguments);
     final T actual = arguments[0];
     if (expected != null && actual != expected)
-      throw 'called $methodName with $T, $actual, which was not exactly the expected $T ($expected).';
+      throw 'It called $methodName with $T, $actual, which was not exactly the expected $T ($expected).';
   }
 
   @override
@@ -601,16 +624,16 @@ class _CirclePaintPredicate extends _DrawCommandPaintPredicate {
     if (x != null && y != null) {
       final Offset point = new Offset(x, y);
       if (point != pointArgument)
-        throw 'called $methodName with a center coordinate, $pointArgument, which was not exactly the expected coordinate ($point).';
+        throw 'It called $methodName with a center coordinate, $pointArgument, which was not exactly the expected coordinate ($point).';
     } else {
       if (x != null && pointArgument.dx != x)
-        throw 'called $methodName with a center coordinate, $pointArgument, whose x-coordinate not exactly the expected coordinate (${x.toStringAsFixed(1)}).';
+        throw 'It called $methodName with a center coordinate, $pointArgument, whose x-coordinate not exactly the expected coordinate (${x.toStringAsFixed(1)}).';
       if (y != null && pointArgument.dy != y)
-        throw 'called $methodName with a center coordinate, $pointArgument, whose y-coordinate not exactly the expected coordinate (${y.toStringAsFixed(1)}).';
+        throw 'It called $methodName with a center coordinate, $pointArgument, whose y-coordinate not exactly the expected coordinate (${y.toStringAsFixed(1)}).';
     }
     final double radiusArgument = arguments[1];
     if (radius != null && radiusArgument != radius)
-      throw 'called $methodName with radius, ${radiusArgument.toStringAsFixed(1)}, which was not exactly the expected radius (${radius.toStringAsFixed(1)}).';
+      throw 'It called $methodName with radius, ${radiusArgument.toStringAsFixed(1)}, which was not exactly the expected radius (${radius.toStringAsFixed(1)}).';
   }
 
   @override
@@ -654,24 +677,24 @@ class _SomethingPaintPredicate extends _PaintPredicate {
   final PaintPatternPredicate predicate;
 
   @override
-  void match(Iterator<Invocation> call) {
+  void match(Iterator<RecordedInvocation> call) {
     assert(predicate != null);
-    Invocation currentCall;
+    RecordedInvocation currentCall;
     do {
       currentCall = call.current;
       if (currentCall == null)
-        throw 'did not call anything that was matched by the predicate passed to a "something" step of the paint pattern.';
-      if (!currentCall.isMethod)
-        throw 'called ${_describeInvocation(currentCall)}, which was not a method, when the paint pattern expected a method call';
+        throw 'It did not call anything that was matched by the predicate passed to a "something" step of the paint pattern.';
+      if (!currentCall.invocation.isMethod)
+        throw 'It called $currentCall, which was not a method, when the paint pattern expected a method call';
       call.moveNext();
-    } while (!_runPredicate(currentCall.memberName, currentCall.positionalArguments));
+    } while (!_runPredicate(currentCall.invocation.memberName, currentCall.invocation.positionalArguments));
   }
 
   bool _runPredicate(Symbol methodName, List<dynamic> arguments) {
     try {
       return predicate(methodName, arguments);
     } on String catch (s) {
-      throw 'painted something that the predicate passed to a "something" step '
+      throw 'It painted something that the predicate passed to a "something" step '
             'in the paint pattern considered incorrect:\n      $s\n  ';
     }
   }
@@ -688,23 +711,28 @@ class _FunctionPaintPredicate extends _PaintPredicate {
   final List<dynamic> arguments;
 
   @override
-  void match(Iterator<Invocation> call) {
+  void match(Iterator<RecordedInvocation> call) {
     int others = 0;
-    final Invocation firstCall = call.current;
-    while (!call.current.isMethod || call.current.memberName != symbol) {
+    final RecordedInvocation firstCall = call.current;
+    while (!call.current.invocation.isMethod || call.current.invocation.memberName != symbol) {
       others += 1;
       if (!call.moveNext())
-        throw 'called $others other method${ others == 1 ? "" : "s" } on the canvas, '
-              'the first of which was ${_describeInvocation(firstCall)}, but did not '
-              'call ${_symbolName(symbol)}() at the time where $this was expected.';
+        throw new _MismatchedCall(
+          'It called $others other method${ others == 1 ? "" : "s" } on the canvas, '
+          'the first of which was $firstCall, but did not '
+          'call ${_symbolName(symbol)}() at the time where $this was expected.',
+          'The first method that was called when the call to ${_symbolName(symbol)}() '
+          'was expected, $firstCall, was called with the following stack:',
+          firstCall,
+        );
     }
-    if (call.current.positionalArguments.length != arguments.length)
-      throw 'called ${_symbolName(symbol)} with ${call.current.positionalArguments.length} arguments; expected ${arguments.length}.';
+    if (call.current.invocation.positionalArguments.length != arguments.length)
+      throw 'It called ${_symbolName(symbol)} with ${call.current.invocation.positionalArguments.length} arguments; expected ${arguments.length}.';
     for (int index = 0; index < arguments.length; index += 1) {
-      final dynamic actualArgument = call.current.positionalArguments[index];
+      final dynamic actualArgument = call.current.invocation.positionalArguments[index];
       final dynamic desiredArgument = arguments[index];
       if (desiredArgument != null && desiredArgument != actualArgument)
-        throw 'called ${_symbolName(symbol)} with argument $index having value ${_valueName(actualArgument)} when ${_valueName(desiredArgument)} was expected.';
+        throw 'It called ${_symbolName(symbol)} with argument $index having value ${_valueName(actualArgument)} when ${_valueName(desiredArgument)} was expected.';
     }
     call.moveNext();
   }
@@ -720,24 +748,29 @@ class _FunctionPaintPredicate extends _PaintPredicate {
 
 class _SaveRestorePairPaintPredicate extends _PaintPredicate {
   @override
-  void match(Iterator<Invocation> call) {
+  void match(Iterator<RecordedInvocation> call) {
     int others = 0;
-    final Invocation firstCall = call.current;
-    while (!call.current.isMethod || call.current.memberName != #save) {
+    final RecordedInvocation firstCall = call.current;
+    while (!call.current.invocation.isMethod || call.current.invocation.memberName != #save) {
       others += 1;
       if (!call.moveNext())
-        throw 'called $others other method${ others == 1 ? "" : "s" } on the canvas, '
-              'the first of which was ${_describeInvocation(firstCall)}, but did not '
-              'call save() at the time where $this was expected.';
+        throw new _MismatchedCall(
+          'It called $others other method${ others == 1 ? "" : "s" } on the canvas, '
+          'the first of which was $firstCall, but did not '
+          'call save() at the time where $this was expected.',
+          'The first method that was called when the call to save() '
+          'was expected, $firstCall, was called with the following stack:',
+          firstCall,
+        );
     }
     int depth = 1;
     while (depth > 0) {
       if (!call.moveNext())
-        throw 'did not have a matching restore() for the save() that was found where $this was expected.';
-      if (call.current.isMethod) {
-        if (call.current.memberName == #save)
+        throw 'It did not have a matching restore() for the save() that was found where $this was expected.';
+      if (call.current.invocation.isMethod) {
+        if (call.current.invocation.memberName == #save)
           depth += 1;
-        else if (call.current.memberName == #restore)
+        else if (call.current.invocation.memberName == #restore)
           depth -= 1;
       }
     }
@@ -761,25 +794,3 @@ String _symbolName(Symbol symbol) {
   final String s = '$symbol';
   return s.substring(8, s.length - 2);
 }
-
-// Workaround for https://github.com/dart-lang/sdk/issues/28373
-String _describeInvocation(Invocation call) {
-  final StringBuffer buffer = new StringBuffer();
-  buffer.write(_symbolName(call.memberName));
-  if (call.isSetter) {
-    buffer.write(call.positionalArguments[0].toString());
-  } else if (call.isMethod) {
-    buffer.write('(');
-    buffer.writeAll(call.positionalArguments.map<String>(_valueName), ', ');
-    String separator = call.positionalArguments.isEmpty ? '' : ', ';
-    call.namedArguments.forEach((Symbol name, Object value) {
-      buffer.write(separator);
-      buffer.write(_symbolName(name));
-      buffer.write(': ');
-      buffer.write(_valueName(value));
-      separator = ', ';
-    });
-    buffer.write(')');
-  }
-  return buffer.toString();
-}

packages/flutter/test/rendering/recording_canvas.dart

@@ -2,8 +2,34 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
 
+/// An [Invocation] and the [stack] trace that led to it.
+///
+/// Used by [TestRecordingCanvas] to trace canvas calls.
+class RecordedInvocation {
+  /// Create a record for an invocation list.
+  const RecordedInvocation(this.invocation, { this.stack });
+
+  /// The method that was called and its arguments.
+  final Invocation invocation;
+
+  /// The stack trace at the time of the method call.
+  final StackTrace stack;
+
+  @override
+  String toString() => _describeInvocation(invocation);
+
+  /// Converts [stack] to a string using the [FlutterError.defaultStackFilter] logic.
+  String stackToString({ String indent: '' }) {
+    assert(indent != null);
+    return indent + FlutterError.defaultStackFilter(
+      stack.toString().trimRight().split('\n')
+    ).join('\n$indent');
+  }
+}
+
 /// A [Canvas] for tests that records its method calls.
 ///
 /// This class can be used in conjuction with [TestRecordingPaintingContext]
@@ -25,7 +51,7 @@ import 'package:flutter/rendering.dart';
 /// pattern matching API over [TestRecordingCanvas].
 class TestRecordingCanvas implements Canvas {
   /// All of the method calls on this canvas.
-  final List<Invocation> invocations = <Invocation>[];
+  final List<RecordedInvocation> invocations = <RecordedInvocation>[];
 
   int _saveCount = 0;
 
@@ -35,25 +61,25 @@ class TestRecordingCanvas implements Canvas {
   @override
   void save() {
     _saveCount += 1;
-    invocations.add(new _MethodCall(#save));
+    invocations.add(new RecordedInvocation(new _MethodCall(#save), stack: StackTrace.current));
   }
 
   @override
   void saveLayer(Rect bounds, Paint paint) {
     _saveCount += 1;
-    invocations.add(new _MethodCall(#saveLayer, <dynamic>[bounds, paint]));
+    invocations.add(new RecordedInvocation(new _MethodCall(#saveLayer, <dynamic>[bounds, paint]), stack: StackTrace.current));
   }
 
   @override
   void restore() {
     _saveCount -= 1;
     assert(_saveCount >= 0);
-    invocations.add(new _MethodCall(#restore));
+    invocations.add(new RecordedInvocation(new _MethodCall(#restore), stack: StackTrace.current));
   }
 
   @override
   void noSuchMethod(Invocation invocation) {
-    invocations.add(invocation);
+    invocations.add(new RecordedInvocation(invocation, stack: StackTrace.current));
   }
 }
 
@@ -101,3 +127,39 @@ class _MethodCall implements Invocation {
   @override
   List<dynamic> get positionalArguments => _arguments;
 }
+
+String _valueName(Object value) {
+  if (value is double)
+    return value.toStringAsFixed(1);
+  return value.toString();
+}
+
+// Workaround for https://github.com/dart-lang/sdk/issues/28372
+String _symbolName(Symbol symbol) {
+  // WARNING: Assumes a fixed format for Symbol.toString which is *not*
+  // guaranteed anywhere.
+  final String s = '$symbol';
+  return s.substring(8, s.length - 2);
+}
+
+// Workaround for https://github.com/dart-lang/sdk/issues/28373
+String _describeInvocation(Invocation call) {
+  final StringBuffer buffer = new StringBuffer();
+  buffer.write(_symbolName(call.memberName));
+  if (call.isSetter) {
+    buffer.write(call.positionalArguments[0].toString());
+  } else if (call.isMethod) {
+    buffer.write('(');
+    buffer.writeAll(call.positionalArguments.map<String>(_valueName), ', ');
+    String separator = call.positionalArguments.isEmpty ? '' : ', ';
+    call.namedArguments.forEach((Symbol name, Object value) {
+      buffer.write(separator);
+      buffer.write(_symbolName(name));
+      buffer.write(': ');
+      buffer.write(_valueName(value));
+      separator = ', ';
+    });
+    buffer.write(')');
+  }
+  return buffer.toString();
+}

packages/flutter/test/widgets/app_overrides_test.dart

@@ -27,15 +27,12 @@ class TestRoute<T> extends PageRoute<T> {
 
 Future<Null> pumpApp(WidgetTester tester) async {
   await tester.pumpWidget(
-    new Directionality(
-      textDirection: TextDirection.ltr,
-      child: new WidgetsApp(
+    new WidgetsApp(
       color: const Color(0xFF333333),
       onGenerateRoute: (RouteSettings settings) {
         return new TestRoute<Null>(settings: settings, child: new Container());
       },
     ),
-    ),
   );
 }
 

packages/flutter/test/widgets/banner_test.dart

@@ -4,8 +4,10 @@
 
 import 'dart:math' as math;
 
-import 'package:flutter/widgets.dart';
-import 'package:test/test.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../rendering/mock_canvas.dart';
 
 class TestCanvas implements Canvas {
   final List<Invocation> invocations = <Invocation>[];
@@ -17,11 +19,16 @@ class TestCanvas implements Canvas {
 }
 
 void main() {
+  // the textDirection values below are intentionally sometimes different and
+  // sometimes the same as the layoutDirection, to make sure that they don't
+  // affect the layout.
+
   test('A Banner with a location of topStart paints in the top left (LTR)', () {
     final BannerPainter bannerPainter = new BannerPainter(
       message: 'foo',
-      textDirection: TextDirection.ltr,
-      location: BannerLocation.topStart
+      textDirection: TextDirection.rtl,
+      location: BannerLocation.topStart,
+      layoutDirection: TextDirection.ltr,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -47,8 +54,9 @@ void main() {
   test('A Banner with a location of topStart paints in the top right (RTL)', () {
     final BannerPainter bannerPainter = new BannerPainter(
       message: 'foo',
-      textDirection: TextDirection.rtl,
+      textDirection: TextDirection.ltr,
       location: BannerLocation.topStart,
+      layoutDirection: TextDirection.rtl,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -75,7 +83,8 @@ void main() {
     final BannerPainter bannerPainter = new BannerPainter(
       message: 'foo',
       textDirection: TextDirection.ltr,
-      location: BannerLocation.topEnd
+      location: BannerLocation.topEnd,
+      layoutDirection: TextDirection.ltr,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -103,6 +112,7 @@ void main() {
       message: 'foo',
       textDirection: TextDirection.rtl,
       location: BannerLocation.topEnd,
+      layoutDirection: TextDirection.rtl,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -129,7 +139,8 @@ void main() {
     final BannerPainter bannerPainter = new BannerPainter(
       message: 'foo',
       textDirection: TextDirection.ltr,
-      location: BannerLocation.bottomStart
+      location: BannerLocation.bottomStart,
+      layoutDirection: TextDirection.ltr,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -157,6 +168,7 @@ void main() {
       message: 'foo',
       textDirection: TextDirection.rtl,
       location: BannerLocation.bottomStart,
+      layoutDirection: TextDirection.rtl,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -182,8 +194,9 @@ void main() {
   test('A Banner with a location of bottomEnd paints in the bottom right (LTR)', () {
     final BannerPainter bannerPainter = new BannerPainter(
       message: 'foo',
-      textDirection: TextDirection.ltr,
-      location: BannerLocation.bottomEnd
+      textDirection: TextDirection.rtl,
+      location: BannerLocation.bottomEnd,
+      layoutDirection: TextDirection.ltr,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -209,8 +222,9 @@ void main() {
   test('A Banner with a location of bottomEnd paints in the bottom left (RTL)', () {
     final BannerPainter bannerPainter = new BannerPainter(
       message: 'foo',
-      textDirection: TextDirection.rtl,
+      textDirection: TextDirection.ltr,
       location: BannerLocation.bottomEnd,
+      layoutDirection: TextDirection.rtl,
     );
 
     final TestCanvas canvas = new TestCanvas();
@@ -233,4 +247,34 @@ void main() {
     expect(rotateCommand.positionalArguments[0], equals(math.PI / 4.0));
   });
 
+  testWidgets('Banner widget', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Banner(message: 'Hello', location: BannerLocation.topEnd),
+      ),
+    );
+    expect(find.byType(CustomPaint), paints
+      ..save
+      ..translate(x: 800.0, y: 0.0)
+      ..rotate(angle: math.PI / 4.0)
+      ..rect(rect: new Rect.fromLTRB(-40.0, 28.0, 40.0, 40.0), color: const Color(0x7f000000), hasMaskFilter: true)
+      ..rect(rect: new Rect.fromLTRB(-40.0, 28.0, 40.0, 40.0), color: const Color(0xa0b71c1c), hasMaskFilter: false)
+      ..paragraph(offset: const Offset(-40.0, 29.0))
+      ..restore
+    );
+  });
+
+  testWidgets('Banner widget in MaterialApp', (WidgetTester tester) async {
+    await tester.pumpWidget(new MaterialApp(home: const Placeholder()));
+    expect(find.byType(CheckedModeBanner), paints
+      ..save
+      ..translate(x: 800.0, y: 0.0)
+      ..rotate(angle: math.PI / 4.0)
+      ..rect(rect: new Rect.fromLTRB(-40.0, 28.0, 40.0, 40.0), color: const Color(0x7f000000), hasMaskFilter: true)
+      ..rect(rect: new Rect.fromLTRB(-40.0, 28.0, 40.0, 40.0), color: const Color(0xa0b71c1c), hasMaskFilter: false)
+      ..paragraph(offset: const Offset(-40.0, 24.0))
+      ..restore
+    );
+  });
 }