add tests for TextUtils
add tests for TextUtils

suzuki/review,masawada/review,orangain/review,takahashim/review,masawada/review,krororo/review,suzuki/review,krororo/review,kmuto/review,murashitas/review,orangain/review,murashitas/review,takahashim/review,kmuto/review,kdmsnr/review,kmuto/review,krororo/review,kuad9/review_study,kuad9/review_study