Use [ instead of [[ to test with.
Tests won't fail if we use [[ because they are conditional expressions,
which do not trigger the exit option bats sets with `set -e`.
Unit tests for abs_path
Tests can now mock a git version.
This makes it possible to test fallback scenarios like when using check-ignore for `homeshick track`, which is only available since git 1.8.2.
homeshick behaves differently when git version < 1.8.2
Add negative test case for filenames with newlines
Add testcase for invoking invalid command
The new suite is called "misc" for lack of a better name.