Pseudo-localization
Also called: Pseudo-locale
Replacing text with longer, accented fake text to find untranslated strings and truncation early.
Definition
Android and Xcode offer pseudo-locales. Any plain English text that remains is hard-coded, and anything cut off will break in long real languages.
In practice
'[Þļåçé öŕðéŕ !!!]' instead of 'Place order' shows the button is too narrow.