Add Jest test for utils.ts (#11)

[ttsukagoshi]

Progress in #11

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🔴	Statements	15.25% (-84.75% 🔻)	167/1095
🔴	Branches	57.14% (-42.86% 🔻)	12/21
🔴	Functions	33.33% (-66.67% 🔻)	4/12
🔴	Lines	15.25% (-84.75% 🔻)	167/1095

Show new covered files 🐣

St.❔	File	Statements	Branches	Functions	Lines
🔴	axe-scan-error.ts	0%	0%	0%	0%
🔴	commands/config.ts	0%	0%	0%	0%
🔴	commands/init.ts	0%	0%	0%	0%
🔴	commands/run.ts	0%	0%	0%	0%
🔴	commands/summary.ts	0%	0%	0%	0%
🟢	constants.ts	100%	0%	100%	100%
🔴	index.ts	0%	0%	0%	0%
🔴	inquirer.ts	0%	0%	0%	0%
🔴	messages.ts	0%	0%	0%	0%
🟢	utils.ts	100%	100%	100%	100%

Test suite run success

9 tests passing in 1 suite.

Report generated by 🧪jest coverage report action from cd01cd2