.include "validation.a"

nmi_count = 10

nmi: inc  <nmi_count
     rti

init_tests:
     sei
     lda  #0
     sta  $2000
     sta  $2001
     jsr  wait_vbl
     jsr  wait_vbl
     lda  #$80           ; enable nmi
     sta  $2000
     rts
     .code

begin_test:
     sta  <result
     
     ; synchronize with nmi and clear
     lda  #-1
     sta  <nmi_count
:    cmp  <nmi_count
     beq  -
     
     rts
     .code

end_test:
     lda  <nmi_count
     jsr  error_if_ne    ; too soon
     inc  <result
     lda  <nmi_count
     jsr  error_if_eq    ; too late
     rts
     .code