test: save buffer content to file instead of printing it in Emacs tests

Before the change, the common Emacs test scheme was to print
buffer content to stdout and redirect it to a file or capture it
in a shell variable.  This does not work if we switch to using
emacsclient(1) for running the tests, because you can not print
to the stdout in this case. (Actually, you can print to stdout
from Emacs server, but you can not capture the output on
emacsclient(1)).

The patch introduces new Emacs test auxiliary functions:
`test-output' and `test-visible-output'.  These functions are
used to save buffer content to a file directly from Emacs.  For
most tests the changes are trivial, because Emacs stdout output
was redirected to a file anyway.  But some tests captured the
output in a shell variable and compare it with the expected
output using test_expect_equal.  These tests are changed to use
files and test_expect_equal_file instead.

Note: even if we do not switch Emacs tests to emacsclient(1), the
patch makes tests cleaner and is an improvement.

3 files changed, 62 insertions, 42 deletions

diff --git a/test/emacs b/test/emacs
index fddb4a1c..8f8b841f 100755
--- a/test/emacs
+++ b/test/emacs
@@ -8,7 +8,7 @@ add_email_corpus
 
 test_begin_subtest "Basic notmuch-hello view in emacs"
 test_emacs '(notmuch-hello)
-	    (princ (buffer-string))' >OUTPUT
+	    (test-output)'
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-hello
 
 test_begin_subtest "Saved search with 0 results"
@@ -18,20 +18,20 @@ test_emacs '(setq notmuch-show-empty-saved-searches t)
 		       ("unread" . "tag:unread")
 		       ("empty" . "tag:doesnotexist")))
 	    (notmuch-hello)
-	    (princ (buffer-string))' >OUTPUT
+	    (test-output)'
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-hello-with-empty
 
 test_begin_subtest "No saved searches displayed (all with 0 results)"
 test_emacs '(setq notmuch-saved-searches
 		  '\''(("empty" . "tag:doesnotexist")))
 	    (notmuch-hello)
-	    (princ (buffer-string))' >OUTPUT
+	    (test-output)'
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-hello-no-saved-searches
 
 test_begin_subtest "Basic notmuch-search view in emacs"
 test_emacs '(notmuch-search "tag:inbox")
 	    (notmuch-test-wait)
-	    (princ (buffer-string))' >OUTPUT
+	    (test-output)'
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-search-tag-inbox
 
 test_begin_subtest "Navigation of notmuch-hello to search results"
@@ -40,27 +40,30 @@ test_emacs '(notmuch-hello)
 	    (re-search-forward "inbox")
 	    (widget-button-press (point))
 	    (notmuch-test-wait)
-	    (princ (buffer-string))' >OUTPUT
+	    (test-output)'
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-hello-view-inbox
 
 test_begin_subtest "Basic notmuch-show view in emacs"
 maildir_storage_thread=$(notmuch search --output=threads id:20091117190054.GU3165@dottiness.seas.harvard.edu)
 test_emacs "(notmuch-show \"$maildir_storage_thread\")
-	    (princ (buffer-string))" >OUTPUT
+	    (test-output)"
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-show-thread-maildir-storage
 
 test_begin_subtest "notmuch-show for message with invalid From"
 add_message "[subject]=\"message-with-invalid-from\"" \
 	    "[from]=\"\\\"Invalid \\\" From\\\" <test_suite@notmuchmail.org>\""
 thread=$(notmuch search --output=threads subject:message-with-invalid-from)
-output=$(test_emacs "(notmuch-show \"$thread\") (princ (buffer-string))")
-test_expect_equal "$output" \
-'"Invalid " From" <test_suite@notmuchmail.org> (2001-01-05) (inbox)
+test_emacs "(notmuch-show \"$thread\")
+	    (test-output)"
+cat <<EOF >EXPECTED
+"Invalid " From" <test_suite@notmuchmail.org> (2001-01-05) (inbox)
 Subject: message-with-invalid-from
 To: Notmuch Test Suite <test_suite@notmuchmail.org>
 Date: Tue, 05 Jan 2001 15:43:57 -0000
 
-This is just a test message (#1)'
+This is just a test message (#1)
+EOF
+test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "Navigation of notmuch-search to thread view"
 test_emacs '(notmuch-search "tag:inbox")
@@ -69,7 +72,7 @@ test_emacs '(notmuch-search "tag:inbox")
 	    (re-search-forward "Working with Maildir")
 	    (notmuch-search-show-thread)
 	    (notmuch-test-wait)
-	    (princ (buffer-string))' >OUTPUT
+	    (test-output)'
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-show-thread-maildir-storage
 
 test_begin_subtest "Add tag from search view"
@@ -162,7 +165,7 @@ test_expect_equal "$output" "thread:XXX   1974-03-29 [1/1] Notmuch Test Suite; T
 test_begin_subtest "notmuch-fcc-dirs set to nil"
 test_emacs "(setq notmuch-fcc-dirs nil)
 	    (notmuch-mua-mail)
-	    (princ (buffer-string))" > OUTPUT
+	    (test-output)"
 cat <<EOF >EXPECTED
 From: Notmuch Test Suite <test_suite@notmuchmail.org>
 To: 
@@ -179,7 +182,7 @@ mkdir -p mail/sent-string/tmp
 test_begin_subtest "notmuch-fcc-dirs set to a string"
 test_emacs "(setq notmuch-fcc-dirs \"sent-string\")
 	    (notmuch-mua-mail)
-	    (princ (buffer-string))" > OUTPUT
+	    (test-output)"
 cat <<EOF >EXPECTED
 From: Notmuch Test Suite <test_suite@notmuchmail.org>
 To: 
@@ -202,7 +205,7 @@ test_emacs "(setq notmuch-fcc-dirs
 		  '((\"notmuchmail.org\" . \"sent-list-match\")
 		    (\".*\" . \"failure\")))
 	    (notmuch-mua-mail)
-	    (princ (buffer-string))" > OUTPUT
+	    (test-output)"
 cat <<EOF >EXPECTED
 From: Notmuch Test Suite <test_suite@notmuchmail.org>
 To: 
@@ -222,7 +225,7 @@ test_emacs "(setq notmuch-fcc-dirs
 		  '((\"example.com\" . \"failure\")
 		    (\".*\" . \"sent-list-catch-all\")))
 	    (notmuch-mua-mail)
-	    (princ (buffer-string))" > OUTPUT
+	    (test-output)"
 cat <<EOF >EXPECTED
 From: Notmuch Test Suite <test_suite@notmuchmail.org>
 To: 
@@ -237,7 +240,7 @@ test_emacs "(setq notmuch-fcc-dirs
 		  '((\"example.com\" . \"failure\")
 		    (\"nomatchhere.net\" . \"failure\")))
 	    (notmuch-mua-mail)
-	    (princ (buffer-string))" > OUTPUT
+	    (test-output)"
 cat <<EOF >EXPECTED
 From: Notmuch Test Suite <test_suite@notmuchmail.org>
 To: 
@@ -252,9 +255,9 @@ test_begin_subtest "Reply within emacs"
 test_emacs '(notmuch-search "subject:\"testing message sent via SMTP\"")
 	    (notmuch-test-wait)
 	    (notmuch-search-reply-to-thread)
-	    (princ (buffer-string))' |
-sed -ne '/^From/,$ p' |
-sed -e 's/^In-Reply-To: <.*>$/In-Reply-To: <XXX>/' >OUTPUT
+	    (test-output)'
+sed -i -ne '/^From/,$ p' OUTPUT
+sed -i -e 's/^In-Reply-To: <.*>$/In-Reply-To: <XXX>/' OUTPUT
 cat <<EOF >EXPECTED
 From: Notmuch Test Suite <test_suite@notmuchmail.org>
 To: user@example.com
@@ -284,8 +287,8 @@ test_begin_subtest "View raw message within emacs"
 first_line=$(head -n1 $EXPECTED/raw-message-cf0c4d-52ad0a)
 test_emacs '(notmuch-show "id:cf0c4d610911171136h1713aa59w9cf9aa31f052ad0a@mail.gmail.com")
 	    (notmuch-show-view-raw-message)
-	    (princ (buffer-string))' |
-sed -ne "/$first_line/,\$ p" >OUTPUT
+	    (test-output)'
+sed -i -ne "/$first_line/,\$ p" OUTPUT
 test_expect_equal_file OUTPUT $EXPECTED/raw-message-cf0c4d-52ad0a
 
 test_begin_subtest "Hiding/showing signature in notmuch-show view"
@@ -295,7 +298,7 @@ test_emacs "(notmuch-show \"$maildir_storage_thread\")
 	    (button-activate (button-at (point)))
 	    (search-backward \"Click/Enter to hide.\")
 	    (button-activate (button-at (point)))
-	    (princ (buffer-string))" >OUTPUT
+	    (test-output)"
 test_expect_equal_file OUTPUT $EXPECTED/notmuch-show-thread-maildir-storage
 
 test_begin_subtest "Detection and hiding of top-post quoting of message"
@@ -323,7 +326,7 @@ Q: Why is top-posting such a bad thing?
 A: Top-posting.
 Q: What is the most annoying thing in e-mail?"'
 test_emacs "(notmuch-show \"top-posting\")
-	    (princ (visible-buffer-string))" >OUTPUT
+	    (test-visible-output)"
 echo "Notmuch Test Suite <test_suite@notmuchmail.org> (2001-01-05) (inbox)
 Subject: The problem with top-posting
 To: Notmuch Test Suite <test_suite@notmuchmail.org>
@@ -346,19 +349,17 @@ Thanks for the advice! I will be sure to put it to good use.
 test_expect_equal_file OUTPUT EXPECTED
 
 test_begin_subtest "Hiding message in notmuch-show view"
-output=$(test_emacs '(notmuch-show "id:f35dbb950911171438k5df6eb56k77b6c0944e2e79ae@mail.gmail.com")
-		     (notmuch-show-toggle-message)
-		     (princ (visible-buffer-string))')
-expected=$(cat $EXPECTED/notmuch-show-thread-with-hidden-messages)
-test_expect_equal "$output" "$expected"
+test_emacs '(notmuch-show "id:f35dbb950911171438k5df6eb56k77b6c0944e2e79ae@mail.gmail.com")
+	    (notmuch-show-toggle-message)
+	    (test-visible-output)'
+test_expect_equal_file OUTPUT $EXPECTED/notmuch-show-thread-with-hidden-messages
 
 test_begin_subtest "Hiding message with visible citation in notmuch-show view"
-output=$(test_emacs '(notmuch-show "id:f35dbb950911171438k5df6eb56k77b6c0944e2e79ae@mail.gmail.com")
-		     (search-forward "Click/Enter to show.")
-		     (button-activate (button-at (point)))
-		     (notmuch-show-toggle-message)
-		     (princ (visible-buffer-string))')
-expected=$(cat $EXPECTED/notmuch-show-thread-with-hidden-messages)
-test_expect_equal "$output" "$expected"
+test_emacs '(notmuch-show "id:f35dbb950911171438k5df6eb56k77b6c0944e2e79ae@mail.gmail.com")
+	    (search-forward "Click/Enter to show.")
+	    (button-activate (button-at (point)))
+	    (notmuch-show-toggle-message)
+	    (test-visible-output)'
+test_expect_equal_file OUTPUT $EXPECTED/notmuch-show-thread-with-hidden-messages
 
 test_done
diff --git a/test/emacs-large-search-buffer b/test/emacs-large-search-buffer
index c78ce334..6095e9da 100755
--- a/test/emacs-large-search-buffer
+++ b/test/emacs-large-search-buffer
@@ -19,16 +19,25 @@ done
 notmuch new > /dev/null
 
 test_begin_subtest "Ensure that emacs doesn't drop results"
-expected="$(notmuch search '*' | sed -e 's/^thread:[0-9a-f]*  //' -e 's/;//' -e  's/xx*/[BLOB]/')
-End of search results."
+notmuch search '*' > EXPEXTED
+sed -i -e 's/^thread:[0-9a-f]*  //' -e 's/;//' -e 's/xx*/[BLOB]/' EXPEXTED
+echo 'End of search results.' >> EXPEXTED
 
-output=$(test_emacs '(notmuch-search "*") (notmuch-test-wait) (princ (buffer-string))' | sed -e s',  *, ,g' -e 's/xxx*/[BLOB]/g')
-test_expect_equal "$output" "$expected"
+test_emacs '(notmuch-search "*")
+	    (notmuch-test-wait)
+	    (test-output)'
+sed -i -e s',  *, ,g' -e 's/xxx*/[BLOB]/g' OUTPUT
+test_expect_equal_file OUTPUT EXPEXTED
 
 test_begin_subtest "Ensure that emacs doesn't drop error messages"
-output=$(test_emacs '(notmuch-search "--this-option-does-not-exist") (notmuch-test-wait) (princ (buffer-string))')
-test_expect_equal "$output" "Error: Unexpected output from notmuch search:
+test_emacs '(notmuch-search "--this-option-does-not-exist")
+	    (notmuch-test-wait)
+	    (test-output)'
+cat <<EOF >EXPEXTED
+Error: Unexpected output from notmuch search:
 Unrecognized option: --this-option-does-not-exist
-End of search results. (process returned 1)"
+End of search results. (process returned 1)
+EOF
+test_expect_equal_file OUTPUT EXPEXTED
 
 test_done
diff --git a/test/test-lib.el b/test/test-lib.el
index 344a02e8..4e7f5cfc 100644
--- a/test/test-lib.el
+++ b/test/test-lib.el
@@ -28,6 +28,16 @@
   (while (get-buffer-process (current-buffer))
     (sleep-for 0.1)))
 
+(defun test-output (&optional filename)
+  "Save current buffer to file FILENAME.  Default FILENAME is OUTPUT."
+  (write-region (point-min) (point-max) (or filename "OUTPUT")))
+
+(defun test-visible-output (&optional filename)
+  "Save visible text in current buffer to file FILENAME.  Default
+FILENAME is OUTPUT."
+  (let ((text (visible-buffer-string)))
+    (with-temp-file (or filename "OUTPUT") (insert text))))
+
 (defun visible-buffer-string ()
   "Same as `buffer-string', but excludes invisible text."
   (visible-buffer-substring (point-min) (point-max)))