Tests new functions

[edouard-lopez]

related: #74, #56

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⚠️ Breaking changes

If you have customized your config.fish, you might need to update it as:

1. _pure_fresh_session changed from integer to boolean

   -set -g _pure_fresh_session 1
   +set -g _pure_fresh_session true

2. pure_user_host_location has been renamed pure_prompt_begin_with_current_directory and an affirmative statement

   -_pure_set_default pure_user_host_location 0
   +_pure_set_default pure_prompt_begin_with_current_directory true

3. pure_separate_prompt_on_error changed from integer to boolean

   -_pure_set_default pure_separate_prompt_on_error 0
   +_pure_set_default pure_separate_prompt_on_error false

Add tests

Follows refactor from #68:

• _pure_format_time.test.fish
• _pure_parse_directory.test.fish
• _pure_parse_git_branch.test.fish
• _pure_print_prompt.test.fish
• _pure_prompt.test.fish
• _pure_prompt_at.test.fish
• _pure_prompt_beginning.test.fish
• _pure_prompt_command_duration.test.fish
• _pure_prompt_current_folder.test.fish
• _pure_prompt_ending.test.fish
• _pure_prompt_first_line.test.fish
• _pure_prompt_git.test.fish
• _pure_prompt_git_arrows.test.fish
• _pure_prompt_git_branch.test.fish
• _pure_prompt_git_dirty.test.fish
• _pure_prompt_host.test.fish
• _pure_prompt_symbol.test.fish
• _pure_prompt_user.test.fish
• _pure_prompt_user_and_host.test.fish
• _pure_prompt_vimode.test.fish
• _pure_prompt_virtualenv.test.fish
• _pure_set_default.test.fish
• _pure_string_width.test.fish

[rafaelrinaldi]

Thanks for working on this, it's shaping up nicely!