[PATCH 1/1] test/test-lib.sh: use vt100 as dtach terminal if TERM nonexistent or dumb

[Tomi Ollila <tomi.ollila@iki.fi>]

The TERM environment variable is set to 'dumb' when running tests, but
the original value of it is stored for echoing colors and running (emacs
(somewhat interactively) in detached session. Emacs requires some
terminal control sequences to be available for interactive operation.
In case original TERM is (also) 'dumb' (or nonexistent) emacs cannot run
interactively. To fix this problem dtach (and emacs as it's child
process) is run with TERM=vt100 in case original TERM was nonexistent or
dumb. This way there is a chance to run emacs tests with different user
terminals and potentially find problems there.
---
 test/test-lib.sh | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/test/test-lib.sh b/test/test-lib.sh
index 6ce3b31..3bc67f7 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -41,6 +41,10 @@ esac
 # Keep the original TERM for say_color and test_emacs
 ORIGINAL_TERM=$TERM
 
+# dtach(1) provides more capable terminal environment to anything
+# that requires more than dumb terminal...
+[ x"${TERM:-dumb}" = xdumb ] && DTACH_TERM=vt100 || DTACH_TERM=$TERM
+
 # For repeatability, reset the environment to known value.
 LANG=C
 LC_ALL=C
@@ -996,9 +1000,10 @@ test_emacs () {
 		fi
 		server_name="notmuch-test-suite-$$"
 		# start a detached session with an emacs server
-		# user's TERM is given to dtach which assumes a minimally
+		# user's TERM (or 'vt100' om case user's term is nonexistent
+		# or 'dumb') is given to dtach which assumes a minimally
 		# VT100-compatible terminal -- and emacs inherits that
-		TERM=$ORIGINAL_TERM dtach -n "$TEST_TMPDIR/emacs-dtach-socket.$$" \
+		TERM=$DTACH_TERM dtach -n "$TEST_TMPDIR/emacs-dtach-socket.$$" \
 			sh -c "stty rows 24 cols 80; exec '$TMP_DIRECTORY/run_emacs' \
 				--no-window-system \
 				$load_emacs_tests \
-- 
1.8.1