test_emacs_expect_t does ignore Emacs as prerequisite

[Milton Vandersloot <miltonrobertvandersloot1412@protonmail.com>]

Dear notmuch Developers

test_emacs_expect_t ignores that it needs Emacs as a prerequisite.
It seems (by comparing the logic of this function with the logic of other test_* functions, e.g. test_expect_success) that the test for that was introduced later and forgotten in this method.
There might also be more places/other test_* methods which miss this check but I have not checked that as I'm not familiar with the codebase.
Below is a patch for the test_emacs_expect_t function.

Regards
Milton

[PATCH] Let test_emacs_expect_t respect missing external prerequisites

test_emacs_expect_t did not test for missing prerequisites (even though
it called test_emacs which does it). Fix that by testing for missing
prerequisites.

--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -548,6 +548,8 @@ test_emacs_expect_t () {
 		inside_subtest=

 		# Report success/failure.
+		test_check_missing_external_prereqs_ "$test_subtest_name" ||
+		{
 		result=$(cat OUTPUT)
 		if [ "$result" = t ]
 		then
@@ -555,6 +557,7 @@ test_emacs_expect_t () {
 		else
 			test_failure_ "${result}"
 		fi
+		}
 	else
 		# Restore state after the (non) test.
 		exec 1>&6 2>&7		# Restore stdout and stderr