commit - 8dc949b075675abad57847c27ef695ecf419cb62
commit + 0eb2a1f6b10ce032f94216e96df1c4a185b3282e
blob - 1cb43054bbaba6dfe115061e321fe94b01bd16d8
blob + 0d53aa841f05888d803febdf56df90a0379fe5f8
--- exercise
+++ exercise
@@ -174,9 +174,15 @@ proc color {c s} {
     return "\033\[${c}m$s\033\[0m"
 }
 
+proc inconsistent {counters} {
+    dict with counters {
+        expr {$run != $ok + $fail + $error}
+    }
+}
+
 proc notok {counters} {
     dict with counters {
-        expr {$ok!=$run || $fail>0 || $error>0}
+        expr {[inconsistent $counters] || $ok != $run}
     }
 }
 
@@ -259,7 +265,7 @@ proc check_suite_counters {counters} {
         }
     }
 
-    if {!$run == $ok + $fail + $error} {
+    if {[inconsistent $counters]} {
         return -code error -errorcode EXER_SUITE \
             "counters do not sum up: $counters"
     }
@@ -338,7 +344,12 @@ proc main {argc argv} {
     }
     if {!$opts(-q)} {puts [summary $counters]}
 
-    # TODO: sanity-check counters, exit 127 (?) if mismatched
+    # sanity-check counters, exit 127 if mismatched (should never happen)
+    if {[inconsistent $counters]} {
+        puts stderr "[file tail $::argv0]: inconsistent counters: $counters"
+        exit 127
+    }
+
     exit [notok $counters]
 }