Fix gem which command test isolation

[afurm]

Problem

The gem which command reports the filesystem path for a requireable file; test_execute_one_missing verifies it prints the found path and errors on a missing file. The test fails when run in isolation because it relies on gem path/spec state set by other tests.

Fix

Set GEM_HOME/GEM_PATH to @gemhome, call Gem.use_paths(@gemhome), and reset the spec cache before the test runs. Restore the env and gem paths in an ensure block and reset the spec cache afterward.

Testing

• ruby -Ilib:test:bundler/lib test/rubygems/test_gem_commands_which_command.rb -n test_execute_one_missing

[hsbt]

@afurm Sorry my late response. The test currently passes in isolation on master without any changes:

$ ruby -Ilib:test:bundler/lib test/rubygems/test_gem_commands_which_command.rb -n test_execute_one_missing
1 tests, 5 assertions, 0 failures, 0 errors

The TODO comment is simply outdated. I think we just need to remove it rather than adding extra setup/teardown logic.

[afurm]

@afurm Sorry my late response. The test currently passes in isolation on master without any changes:

$ ruby -Ilib:test:bundler/lib test/rubygems/test_gem_commands_which_command.rb -n test_execute_one_missing
1 tests, 5 assertions, 0 failures, 0 errors

The TODO comment is simply outdated. I think we just need to remove it rather than adding extra setup/teardown logic.

Removed comment. Thank you