Tests that install packages with dependencies were failing
when those dependencies were not already installed, because
the count of installed packages was greater than the count
of requested to be installed packages. This change checks
for a count of installed packages that is greater than or
equal to the count of requested to be installed packages.
Example:
- Test installs packages `zsh` and `fish`
- `fish` has a dependency on `pcre2`
- `pkg` reports `Number of packages to be installed: 3`
Several tests need to install an out-of-date package
to test whether upgrades occur successfully, so this
commit refactors out the generation of the test package.
Also, factor out things like the name and path of the
test package so that is more maintainable should the
target test package (currently `zsh`) ever need to
change.
