diff --git a/packages/forge2d/lib/src/dynamics/joints/prismatic_joint.dart b/packages/forge2d/lib/src/dynamics/joints/prismatic_joint.dart
index 077cf574..b5775049 100644
--- a/packages/forge2d/lib/src/dynamics/joints/prismatic_joint.dart
+++ b/packages/forge2d/lib/src/dynamics/joints/prismatic_joint.dart
@@ -275,20 +275,14 @@ class PrismaticJoint extends Joint {
   }
 
   /// Set the motor speed, usually in meters per second.
-  ///
-  /// @param speed
-  void setMotorSpeed(double speed) {
+  set motorSpeed(double speed) {
     bodyA.setAwake(true);
     bodyB.setAwake(true);
     _motorSpeed = speed;
   }
 
   /// Get the motor speed, usually in meters per second.
-  ///
-  /// @return
-  double getMotorSpeed() {
-    return _motorSpeed;
-  }
+  double get motorSpeed => _motorSpeed;
 
   /// Set the maximum motor force, usually in N.
   ///
diff --git a/packages/forge2d/lib/src/dynamics/joints/revolute_joint.dart b/packages/forge2d/lib/src/dynamics/joints/revolute_joint.dart
index c919dc5d..efb77687 100644
--- a/packages/forge2d/lib/src/dynamics/joints/revolute_joint.dart
+++ b/packages/forge2d/lib/src/dynamics/joints/revolute_joint.dart
@@ -461,7 +461,7 @@ class RevoluteJoint extends Joint {
     _enableMotor = flag;
   }
 
-  void setMotorSpeed(final double speed) {
+  set motorSpeed(double speed) {
     bodyA.setAwake(true);
     bodyB.setAwake(true);
     _motorSpeed = speed;
diff --git a/packages/forge2d/lib/src/dynamics/joints/wheel_joint.dart b/packages/forge2d/lib/src/dynamics/joints/wheel_joint.dart
index be3f190d..ed165e85 100644
--- a/packages/forge2d/lib/src/dynamics/joints/wheel_joint.dart
+++ b/packages/forge2d/lib/src/dynamics/joints/wheel_joint.dart
@@ -137,15 +137,13 @@ class WheelJoint extends Joint {
     _enableMotor = flag;
   }
 
-  void setMotorSpeed(double speed) {
+  set motorSpeed(double speed) {
     bodyA.setAwake(true);
     bodyB.setAwake(true);
     _motorSpeed = speed;
   }
 
-  double getMotorSpeed() {
-    return _motorSpeed;
-  }
+  double get motorSpeed => _motorSpeed;
 
   double getMaxMotorTorque() {
     return _maxMotorTorque;
diff --git a/packages/forge2d/test/dynamics/joints/prismatic_joint_test.dart b/packages/forge2d/test/dynamics/joints/prismatic_joint_test.dart
index c1c4444c..04a8ce5f 100644
--- a/packages/forge2d/test/dynamics/joints/prismatic_joint_test.dart
+++ b/packages/forge2d/test/dynamics/joints/prismatic_joint_test.dart
@@ -2,37 +2,63 @@ import 'package:forge2d/forge2d.dart';
 import 'package:mocktail/mocktail.dart';
 import 'package:test/test.dart';
 
-import '../../helpers/helpers.dart';
+class _MockBody extends Mock implements Body {}
+
+class _MockDebugDraw extends Mock implements DebugDraw {}
 
 void main() {
   group('PrismaticJoint', () {
-    test('can be instantiated', () {
-      final world = World();
-      final jointDef = PrismaticJointDef()
-        ..bodyA = Body(BodyDef(), world)
-        ..bodyB = Body(BodyDef(), world);
+    late PrismaticJointDef jointDef;
 
+    setUp(
+      () {
+        jointDef = PrismaticJointDef()
+          ..bodyA = _MockBody()
+          ..bodyB = _MockBody();
+      },
+    );
+
+    test('can be instantiated', () {
       expect(PrismaticJoint(jointDef), isA<PrismaticJoint>());
     });
 
+    group('motorSpeed', () {
+      test('can change motor speed', () {
+        final joint = PrismaticJoint(jointDef);
+
+        final oldMotorSpeed = joint.motorSpeed;
+        final newMotorSpeed = oldMotorSpeed + 1;
+        joint.motorSpeed = newMotorSpeed;
+
+        expect(joint.motorSpeed, equals(newMotorSpeed));
+      });
+
+      test('wakes up both bodies', () {
+        final joint = PrismaticJoint(jointDef);
+        joint.motorSpeed = 1;
+
+        verify(() => joint.bodyA.setAwake(true)).called(1);
+        verify(() => joint.bodyB.setAwake(true)).called(1);
+      });
+    });
+
     group('render', () {
-      late World world;
       late DebugDraw debugDraw;
 
       setUp(() {
-        world = World();
-        debugDraw = MockDebugDraw();
+        debugDraw = _MockDebugDraw();
 
         registerFallbackValue(Vector2.zero());
         registerFallbackValue(Color3i.black);
       });
 
       test('draws three segments', () {
-        final joint = PrismaticJoint(
-          PrismaticJointDef()
-            ..bodyA = Body(BodyDef(), world)
-            ..bodyB = Body(BodyDef(), world),
-        );
+        final joint = PrismaticJoint(jointDef);
+        when(() => joint.bodyA.transform).thenReturn(Transform.zero());
+        when(() => joint.bodyB.transform).thenReturn(Transform.zero());
+        when(() => joint.bodyA.worldPoint(any())).thenReturn(Vector2.zero());
+        when(() => joint.bodyB.worldPoint(any())).thenReturn(Vector2.zero());
+
         joint.render(debugDraw);
         verify(() => debugDraw.drawSegment(any(), any(), any())).called(3);
       });
diff --git a/packages/forge2d/test/dynamics/joints/revolute_joint_test.dart b/packages/forge2d/test/dynamics/joints/revolute_joint_test.dart
index 8139e32f..1af79891 100644
--- a/packages/forge2d/test/dynamics/joints/revolute_joint_test.dart
+++ b/packages/forge2d/test/dynamics/joints/revolute_joint_test.dart
@@ -2,37 +2,61 @@ import 'package:forge2d/forge2d.dart';
 import 'package:mocktail/mocktail.dart';
 import 'package:test/test.dart';
 
-import '../../helpers/helpers.dart';
+class _MockBody extends Mock implements Body {}
+
+class _MockDebugDraw extends Mock implements DebugDraw {}
 
 void main() {
   group('RevoluteJoint', () {
-    test('can be instantiated', () {
-      final world = World();
-      final jointDef = RevoluteJointDef()
-        ..bodyA = Body(BodyDef(), world)
-        ..bodyB = Body(BodyDef(), world);
+    late RevoluteJointDef jointDef;
+
+    setUp(() {
+      jointDef = RevoluteJointDef()
+        ..bodyA = _MockBody()
+        ..bodyB = _MockBody();
+    });
 
+    test('can be instantiated', () {
       expect(RevoluteJoint(jointDef), isA<RevoluteJoint>());
     });
 
+    group('motorSpeed', () {
+      test('can change motor speed', () {
+        final joint = RevoluteJoint(jointDef);
+
+        final oldMotorSpeed = joint.motorSpeed;
+        final newMotorSpeed = oldMotorSpeed + 1;
+        joint.motorSpeed = newMotorSpeed;
+
+        expect(joint.motorSpeed, equals(newMotorSpeed));
+      });
+
+      test('wakes up both bodies', () {
+        final joint = RevoluteJoint(jointDef);
+        joint.motorSpeed = 1;
+
+        verify(() => joint.bodyA.setAwake(true)).called(1);
+        verify(() => joint.bodyB.setAwake(true)).called(1);
+      });
+    });
+
     group('render', () {
-      late World world;
       late DebugDraw debugDraw;
 
       setUp(() {
-        world = World();
-        debugDraw = MockDebugDraw();
+        debugDraw = _MockDebugDraw();
 
         registerFallbackValue(Vector2.zero());
         registerFallbackValue(Color3i.black);
       });
 
       test('draws three segments', () {
-        final joint = RevoluteJoint(
-          RevoluteJointDef()
-            ..bodyA = Body(BodyDef(), world)
-            ..bodyB = Body(BodyDef(), world),
-        );
+        final joint = RevoluteJoint(jointDef);
+        when(() => joint.bodyA.transform).thenReturn(Transform.zero());
+        when(() => joint.bodyB.transform).thenReturn(Transform.zero());
+        when(() => joint.bodyA.worldPoint(any())).thenReturn(Vector2.zero());
+        when(() => joint.bodyB.worldPoint(any())).thenReturn(Vector2.zero());
+
         joint.render(debugDraw);
         verify(() => debugDraw.drawSegment(any(), any(), any())).called(3);
       });
diff --git a/packages/forge2d/test/dynamics/joints/wheel_joint_test.dart b/packages/forge2d/test/dynamics/joints/wheel_joint_test.dart
index 4019637c..d2e193c6 100644
--- a/packages/forge2d/test/dynamics/joints/wheel_joint_test.dart
+++ b/packages/forge2d/test/dynamics/joints/wheel_joint_test.dart
@@ -2,37 +2,61 @@ import 'package:forge2d/forge2d.dart';
 import 'package:mocktail/mocktail.dart';
 import 'package:test/test.dart';
 
-import '../../helpers/helpers.dart';
+class _MockBody extends Mock implements Body {}
+
+class _MockDebugDraw extends Mock implements DebugDraw {}
 
 void main() {
   group('WheelJoint', () {
-    test('can be instantiated', () {
-      final world = World();
-      final jointDef = WheelJointDef()
-        ..bodyA = Body(BodyDef(), world)
-        ..bodyB = Body(BodyDef(), world);
+    late WheelJointDef jointDef;
+
+    setUp(() {
+      jointDef = WheelJointDef()
+        ..bodyA = _MockBody()
+        ..bodyB = _MockBody();
+    });
 
+    test('can be instantiated', () {
       expect(WheelJoint(jointDef), isA<WheelJoint>());
     });
 
+    group('motorSpeed', () {
+      test('can change motor speed', () {
+        final joint = WheelJoint(jointDef);
+
+        final oldMotorSpeed = joint.motorSpeed;
+        final newMotorSpeed = oldMotorSpeed + 1;
+        joint.motorSpeed = newMotorSpeed;
+
+        expect(joint.motorSpeed, equals(newMotorSpeed));
+      });
+
+      test('wakes up both bodies', () {
+        final joint = WheelJoint(jointDef);
+        joint.motorSpeed = 1;
+
+        verify(() => joint.bodyA.setAwake(true)).called(1);
+        verify(() => joint.bodyB.setAwake(true)).called(1);
+      });
+    });
+
     group('render', () {
-      late World world;
       late DebugDraw debugDraw;
 
       setUp(() {
-        world = World();
-        debugDraw = MockDebugDraw();
+        debugDraw = _MockDebugDraw();
 
         registerFallbackValue(Vector2.zero());
         registerFallbackValue(Color3i.black);
       });
 
       test('draws three segments', () {
-        final joint = WheelJoint(
-          WheelJointDef()
-            ..bodyA = Body(BodyDef(), world)
-            ..bodyB = Body(BodyDef(), world),
-        );
+        final joint = WheelJoint(jointDef);
+        when(() => joint.bodyA.transform).thenReturn(Transform.zero());
+        when(() => joint.bodyB.transform).thenReturn(Transform.zero());
+        when(() => joint.bodyA.worldPoint(any())).thenReturn(Vector2.zero());
+        when(() => joint.bodyB.worldPoint(any())).thenReturn(Vector2.zero());
+
         joint.render(debugDraw);
         verify(() => debugDraw.drawSegment(any(), any(), any())).called(3);
       });