Improve test coverage (#5473)

These tests should hit some previously untested lines.
diff --git a/packages/flutter/test/gestures/pointer_router_test.dart b/packages/flutter/test/gestures/pointer_router_test.dart
index 3da96b1..444c461 100644
--- a/packages/flutter/test/gestures/pointer_router_test.dart
+++ b/packages/flutter/test/gestures/pointer_router_test.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
 
 void main() {
@@ -117,4 +118,35 @@
       'global 2',
     ]));
   });
+
+  test('Exceptions do not stop pointer routing', () {
+    List<String> log = <String>[];
+    PointerRouter router = new PointerRouter();
+    router.addRoute(2, (PointerEvent event) {
+      log.add('per-pointer 1');
+    });
+    router.addRoute(2, (PointerEvent event) {
+      log.add('per-pointer 2');
+      throw "Having a bad day!";
+    });
+    router.addRoute(2, (PointerEvent event) {
+      log.add('per-pointer 3');
+    });
+
+    FlutterExceptionHandler previousErrorHandler = FlutterError.onError;
+    FlutterError.onError = (FlutterErrorDetails details) {
+      log.add('error report');
+    };
+
+    TestPointer pointer2 = new TestPointer(2);
+    router.route(pointer2.down(Point.origin));
+    expect(log, equals(<String>[
+      'per-pointer 1',
+      'per-pointer 2',
+      'error report',
+      'per-pointer 3',
+    ]));
+
+    FlutterError.onError = previousErrorHandler;
+  });
 }
diff --git a/packages/flutter/test/gestures/recognizer_test.dart b/packages/flutter/test/gestures/recognizer_test.dart
new file mode 100644
index 0000000..c52d1d8
--- /dev/null
+++ b/packages/flutter/test/gestures/recognizer_test.dart
@@ -0,0 +1,27 @@
+// Copyright 2015 The Chromium Authors. 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:flutter_test/flutter_test.dart';
+import 'package:flutter/gestures.dart';
+
+class TestGestureRecognizer extends GestureRecognizer {
+  @override
+  String toString() => 'toString content';
+
+  @override
+  void addPointer(PointerDownEvent event) {}
+
+  @override
+  void acceptGesture(int pointer) {}
+
+  @override
+  void rejectGesture(int pointer) {}
+}
+
+void main() {
+  test('GestureRecognizer.toStringShort defaults to toString', () {
+    TestGestureRecognizer recognizer = new TestGestureRecognizer();
+    expect(recognizer.toStringShort(), equals(recognizer.toString()));
+  });
+}
diff --git a/packages/flutter/test/gestures/velocity_tracker_test.dart b/packages/flutter/test/gestures/velocity_tracker_test.dart
index 44a53c9..1beeebb 100644
--- a/packages/flutter/test/gestures/velocity_tracker_test.dart
+++ b/packages/flutter/test/gestures/velocity_tracker_test.dart
@@ -54,6 +54,8 @@
     expect(velocity1, equals(new Velocity(pixelsPerSecond: new Offset(7.0, 0.0))));
     expect(velocity1, isNot(equals(velocity2)));
     expect(velocity2 - velocity1, equals(new Velocity(pixelsPerSecond: new Offset(5.0, 0.0))));
+    expect((-velocity1).pixelsPerSecond, new Offset(-7.0, 0.0));
+    expect(velocity1 + velocity2, equals(new Velocity(pixelsPerSecond: new Offset(19.0, 0.0))));
     expect(velocity1.hashCode, isNot(equals(velocity2.hashCode)));
     expect(velocity1, hasOneLineDescription);
   });
diff --git a/packages/flutter/test/painting/box_painter_test.dart b/packages/flutter/test/painting/box_painter_test.dart
new file mode 100644
index 0000000..abaccb5
--- /dev/null
+++ b/packages/flutter/test/painting/box_painter_test.dart
@@ -0,0 +1,79 @@
+// Copyright 2016 The Chromium Authors. 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:flutter_test/flutter_test.dart';
+import 'package:flutter/painting.dart';
+
+void main() {
+  test("BorderSide control test", () {
+    BorderSide side1 = new BorderSide();
+    BorderSide side2 = side1.copyWith(
+      color: const Color(0xFF00FFFF),
+      width: 2.0,
+      style: BorderStyle.solid,
+    );
+
+    expect(side1, hasOneLineDescription);
+    expect(side1.hashCode, isNot(equals(side2.hashCode)));
+
+    expect(side2.color, equals(const Color(0xFF00FFFF)));
+    expect(side2.width, equals(2.0));
+    expect(side2.style, equals(BorderStyle.solid));
+
+    expect(BorderSide.lerp(side1, side2, 0.0), equals(side1));
+    expect(BorderSide.lerp(side1, side2, 1.0), equals(side2));
+    expect(BorderSide.lerp(side1, side2, 0.5), equals(new BorderSide(
+      color: Color.lerp(const Color(0xFF000000), const Color(0xFF00FFFF), 0.5),
+      width: 1.5,
+      style: BorderStyle.solid,
+    )));
+
+    BorderSide side3 = side2.copyWith(style: BorderStyle.none);
+    BorderSide interpolated = BorderSide.lerp(side2, side3, 0.2);
+    expect(interpolated.style, equals(BorderStyle.solid));
+    expect(interpolated.color, equals(side2.color.withOpacity(0.8)));
+
+    interpolated = BorderSide.lerp(side3, side2, 0.2);
+    expect(interpolated.style, equals(BorderStyle.solid));
+    expect(interpolated.color, equals(side2.color.withOpacity(0.2)));
+  });
+
+  test("Border control test", () {
+    Border border1 = new Border.all(width: 4.0);
+    Border border2 = Border.lerp(null, border1, 0.25);
+    Border border3 = Border.lerp(border1, null, 0.25);
+
+    expect(border1, hasOneLineDescription);
+    expect(border1.hashCode, isNot(equals(border2.hashCode)));
+
+    expect(border2.top.width, equals(1.0));
+    expect(border3.bottom.width, equals(3.0));
+
+    Border border4 = Border.lerp(border2, border3, 0.5);
+    expect(border4.left.width, equals(2.0));
+  });
+
+  test("BoxShadow control test", () {
+    BoxShadow shadow1 = new BoxShadow(blurRadius: 4.0);
+    BoxShadow shadow2 = BoxShadow.lerp(null, shadow1, 0.25);
+    BoxShadow shadow3 = BoxShadow.lerp(shadow1, null, 0.25);
+
+    expect(shadow1, hasOneLineDescription);
+    expect(shadow1.hashCode, isNot(equals(shadow2.hashCode)));
+    expect(shadow1, equals(new BoxShadow(blurRadius: 4.0)));
+
+    expect(shadow2.blurRadius, equals(1.0));
+    expect(shadow3.blurRadius, equals(3.0));
+
+    BoxShadow shadow4 = BoxShadow.lerp(shadow2, shadow3, 0.5);
+    expect(shadow4.blurRadius, equals(2.0));
+
+    List<BoxShadow> shadowList = BoxShadow.lerpList(
+        <BoxShadow>[shadow2, shadow1], <BoxShadow>[shadow3], 0.5);
+    expect(shadowList, equals(<BoxShadow>[shadow4, shadow1.scale(0.5)]));
+    shadowList = BoxShadow.lerpList(
+        <BoxShadow>[shadow2], <BoxShadow>[shadow3, shadow1], 0.5);
+    expect(shadowList, equals(<BoxShadow>[shadow4, shadow1.scale(0.5)]));
+  });
+}
diff --git a/packages/flutter/test/rendering/debug_test.dart b/packages/flutter/test/rendering/debug_test.dart
new file mode 100644
index 0000000..581f810
--- /dev/null
+++ b/packages/flutter/test/rendering/debug_test.dart
@@ -0,0 +1,20 @@
+// Copyright 2015 The Chromium Authors. 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:flutter/rendering.dart';
+import 'package:test/test.dart';
+import 'package:vector_math/vector_math_64.dart';
+
+void main() {
+  test("Describe transform control test", () {
+    Matrix4 identity = new Matrix4.identity();
+    List<String> description = debugDescribeTransform(identity);
+    expect(description, equals(<String>[
+      '  [0] 1.0,0.0,0.0,0.0',
+      '  [1] 0.0,1.0,0.0,0.0',
+      '  [2] 0.0,0.0,1.0,0.0',
+      '  [3] 0.0,0.0,0.0,1.0',
+    ]));
+  });
+}