tests: Extend and document the after-a-parse-error aspects of the issue #651 test.

highlighters/main/test-data/array-cmdsep1.zsh

@@ -29,11 +29,16 @@
 # -------------------------------------------------------------------------------------------------
 
 BUFFER=$'a=( foo | bar )'
+bar(){}
 
 expected_region_highlight=(
   '1 3 assign' # a=(
   '5 7 default' # foo
   '9 9 unknown-token' # |
-  '11 13 unknown-token' # bar
+  # zsh reports a parse error at this point.  Nevertheless, we test how we
+  # highlight the remainder of $BUFFER.  Currently we recover by treating the pipe
+  # as a command separator.  That's not the only reasonable behaviour, though; if
+  # we change the behaviour, we should adjust the following expectations accordingly.
+  '11 13 function' # bar
   '15 15 unknown-token' # )
 )