Allow unit tests to test for errors.

test/run

@@ -15,7 +15,11 @@ main() {
     test_files=$(ls out selections state 2>/dev/null)
     cd $work/$dir;
     indent="$(echo "${dir}/" | sed -e 's|[^/]*/\+|  |g')"
-    name=$(basename $PWD)
+    name=$(echo ${PWD##*/} | sed 's/-fail^//')
+    should_fail=0
+    if [ ${PWD##*-} = fail ]; then
+      should_fail=1
+    fi
     if ! test -e cmd; then
       echo "$indent$name"
     elif test -x enabled && ! ./enabled; then
@@ -46,6 +50,7 @@ main() {
       "
       ${test}/../src/kak out -n -u -e "$kak_commands"
       retval=$?
+      if [ $should_fail = 0 ]; then
         if [ $retval -ne 0 ]; then
           echo "Kakoune returned error $retval"
         fi
@@ -72,6 +77,13 @@ main() {
             echo
           fi
         done
+      else
+        if [ $retval -eq 0 ]; then
+          color=red
+        fi
+        color=${color:-green}
+        echo "$indent$name" | colorize $color normal
+      fi
     fi
   done
   if expr $number_failures > 0; then