Test missing argument

[edouard-lopez]

fixes #108

---

Manual install on fish 3.0.0 was incorrect:

~> source /tmp/installer.fish
~> install_pure
Installing Pure theme
	Set environment variable: $FISH_CONFIG_DIR
	Set environment variable: $PURE_INSTALL_DIR
	Checking for git availability ✔
	Fetching theme's source ✔
	Backuping existing theme ✔
	Enabling autoloading for pure's functions on shell init ✔
	Enabling theme ✔
	Cleaning after install ✔
test: Missing argument at index 2
test: Missing argument at index 2
test: Missing argument at index 2
test: Missing argument at index 2

Solution

Source pure.fish in user config.fish to load