isAscending should return true for any positive resolution, including 0 (which is the resolution of an axis with a single value). This condition is used to determine whether min/max indexes should get flipped when a subset is requested, which currently results in an error for the case of an axis with a single value.
Add a test and a small refactor of existing test class (easiest to view diff without whitespace changes).
Description of Changes
Fixes https://github.com/Unidata/tds/issues/532.
isAscendingshould return true for any positiveresolution, including 0 (which is the resolution of an axis with a single value). This condition is used to determine whether min/max indexes should get flipped when a subset is requested, which currently results in an error for the case of an axis with a single value.