files ← ⟨"syntax"⟩⍟(0=≠) ('-'≠⊑)¨⊸/ •args

Native ← Exec ← •BQN

Cases ← (0<≠)◶0‿('#'≠⊑)¨⊸/ · •FLines "cases/"∾∾⟜".bqn"
c ← ∾ Cases¨ files
Trim ← ((∨`∧∨`⌾⌽)' '⊸≠)⊸/
M ← {e‿b←𝕩
  Msg ← {∾⟨
    """",b,""": expected "
    "to fail"⍟("!"⊸≡)e
    " but "
    0⊸≡◶⟨"received "∾·•Fmt⊑,"evaluation failed"⟩𝕩
    ⥊@+10
  ⟩}
  ("!"⊸≡◶⟨<Native,0˙⟩ e) ≢◶""‿Msg <∘Exec⎊0 b
}
r ← (M '%'⊸= (∨´⊣)◶⟨"1"≍○<⊢, Trim¨(+`-2⊸×)⊸⊔⟩ ⊢)¨ c
•Out ("All "∾(•Fmt≠c)∾" passed!")⍟(0=≠) ¯1↓∾r