[PATCH 1/3] test: Clear test-ouput output file before running Emacs tests

[Austin Clements <amdragon@MIT.EDU>]

Most Emacs tests end with a call to (test-output), which saves the
buffer to a filed called OUTPUT.  Previously, if the test code failed
with an exception before this call, the test framework would then
compare against the OUTPUT file from the last Emacs test, resulting in
confusing diffs.

This requires one tweak to an emacs test that made two calls to
test_emacs and expected an OUTPUT file from the first call.  We simply
reverse the order of the test_emacs calls.
---
 test/emacs       |    4 ++--
 test/test-lib.sh |    8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/test/emacs b/test/emacs
index 5d118b6..174a9ac 100755
--- a/test/emacs
+++ b/test/emacs
@@ -653,6 +653,8 @@ test_expect_equal "$(cat OUTPUT)" "thread:XXX"
 test_begin_subtest 'notmuch-show-advance-and-archive with invisible signature'
 message1='id:20091118010116.GC25380@dottiness.seas.harvard.edu'
 message2='id:1258491078-29658-1-git-send-email-dottedmag@dottedmag.net'
+test_emacs "(notmuch-show \"$message2\")
+	    (test-output \"EXPECTED\")"
 test_emacs "(notmuch-search \"$message1 or $message2\")
 	    (notmuch-test-wait)
 	    (notmuch-search-show-thread)
@@ -660,8 +662,6 @@ test_emacs "(notmuch-search \"$message1 or $message2\")
 	    (redisplay)
 	    (notmuch-show-advance-and-archive)
 	    (test-output)"
-test_emacs "(notmuch-show \"$message2\")
-	    (test-output \"EXPECTED\")"
 test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "Refresh show buffer"
diff --git a/test/test-lib.sh b/test/test-lib.sh
index f34b1fb..7448b45 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -985,6 +985,14 @@ test_emacs () {
 		done
 	fi
 
+	# Clear test-output output file.  Most Emacs tests end with a
+	# call to (test-output).  If the test code fails with an
+	# exception before this call, the output file won't get
+	# updated.  Since we don't want to compare against an output
+	# file from another test, so start out with an empty file.
+	rm -f OUTPUT
+	touch OUTPUT
+
 	emacsclient --socket-name="$EMACS_SERVER" --eval "(progn $@)"
 }
 
-- 
1.7.10