slippy.RangeFamilyAt doesn't return self or parents

[jchamberlain]

Problem

RangeFamilyAt was rewritten in PR #99 and its behavior fundamentally changed. Previously, it returned:

1. The tile itself, plus
2. If zoom is less than the tile's zoom, all tiles ancestors at the specified zoom,
3. If zoom is greater than the tile's zoom, all tile's descendants at the specified zoom.

After PR #99 it returns only (3). In addition, floating point error introduced by FromNative and ToNative cause the function's output to be unpredictable and therefore difficult to test (see #127).

PR #99 commented out the failing test: d04b99a#diff-e7c11f2955e26a4cf0f286e7b5eb5da15c1e475bf3fb386ad134449680f31354R56

Solution

Unknown. I don't know the background of this function, but Tegola's tests expect it to function the old way, not the new way.