fix negative width/height of rectangle (#4074)

Rectangle test updates (#3578) ...

* Rectangle tests
Converted to arrow functions
Added new tests and new cases to existing tests
Removed unreachable ternary in Rectangle.pad()
Fixed invalid comparison in Rectangle.enlarge()
Changed param name in Rectangle.enlarge(rectangle) to match other methods

* Reverted ternary change in Rectangle.pad()
Removed empty Rectangle check in Rectangle.enlarge()
Additional Rectangle.fit() test

* Fixed Rectangle.enlarge() test to account for changed logic if passed Rectangle is empty

* Changed arrow functions back to regular functions in Rectangle.js tests

Added basic tests for math shape: Circle and Rectangle (#3129) ...

* Added basic test for math shape: Circle and Rectangle

* Fixing lint

* Fixing lint again