| Testfehler | Nominativ, Singular | nominative case, singular | |
| Testfehler(e)s | Genitiv, Singular | genitive case, singular | |
| Testfehler(e) | Dativ, Singular | dative case, singular | |
| Testfehler | Akkusativ, Singular | accusative case, singular | |
| Testfehlere | Nominativ, Plural | nominative case, plural | |
| Testfehlere | Genitiv, Plural | genitive case, plural | |
| Testfehleren | Dativ, Plural | dative case, plural | |
| Testfehlere | Akkusativ, Plural | accusative case, plural |