coversSameAreaAs function
Asserts that 2 paths cover the same area by sampling multiple points.
Samples at least sampleSize^2 points inside areaToCompare, and asserts
that the Path.contains method returns the same value for each of the
points for both paths.
When using this matcher you typically want to use a rectangle larger than
the area you expect to paint in for areaToCompare to catch errors where
the path draws outside the expected area.
Implementation
Matcher coversSameAreaAs(Path expectedPath, {@required Rect areaToCompare, int sampleSize = 20})
=> _CoversSameAreaAs(expectedPath, areaToCompare: areaToCompare, sampleSize: sampleSize);