diff --git a/test/T300-encoding.sh b/test/T300-encoding.sh
index 1e9d2a3d..6fcd10c5 100755
--- a/test/T300-encoding.sh
+++ b/test/T300-encoding.sh
@@ -31,18 +31,18 @@ test_expect_equal "$output" "thread:0000000000000002   2001-01-05 [1/1] Notmuch
 
 test_begin_subtest "RFC 2047 encoded word with spaces"
 add_message '[subject]="=?utf-8?q?encoded word with spaces?="'
-output=$(notmuch search id:${gen_msg_id} 2>&1 | notmuch_show_sanitize)
-test_expect_equal "$output" "thread:0000000000000003   2001-01-05 [1/1] Notmuch Test Suite; encoded word with spaces (inbox unread)"
+output=$(notmuch search id:${gen_msg_id} 2>&1 | notmuch_search_sanitize)
+test_expect_equal "$output" "thread:XXX   2001-01-05 [1/1] Notmuch Test Suite; encoded word with spaces (inbox unread)"
 
 test_begin_subtest "RFC 2047 encoded words back to back"
 add_message '[subject]="=?utf-8?q?encoded-words-back?==?utf-8?q?to-back?="'
-output=$(notmuch search id:${gen_msg_id} 2>&1 | notmuch_show_sanitize)
-test_expect_equal "$output" "thread:0000000000000004   2001-01-05 [1/1] Notmuch Test Suite; encoded-words-backto-back (inbox unread)"
+output=$(notmuch search id:${gen_msg_id} 2>&1 | notmuch_search_sanitize)
+test_expect_equal "$output" "thread:XXX   2001-01-05 [1/1] Notmuch Test Suite; encoded-words-backto-back (inbox unread)"
 
 test_begin_subtest "RFC 2047 encoded words without space before or after"
 add_message '[subject]="=?utf-8?q?encoded?=word without=?utf-8?q?space?=" '
-output=$(notmuch search id:${gen_msg_id} 2>&1 | notmuch_show_sanitize)
-test_expect_equal "$output" "thread:0000000000000005   2001-01-05 [1/1] Notmuch Test Suite; encodedword withoutspace (inbox unread)"
+output=$(notmuch search id:${gen_msg_id} 2>&1 | notmuch_search_sanitize)
+test_expect_equal "$output" "thread:XXX   2001-01-05 [1/1] Notmuch Test Suite; encodedword withoutspace (inbox unread)"
 
 test_begin_subtest "Mislabeled Windows-1252 encoding"
 add_message '[content-type]="text/plain; charset=iso-8859-1"'                           \
diff --git a/test/T310-emacs.sh b/test/T310-emacs.sh
index 1ece6e00..b94236fd 100755
--- a/test/T310-emacs.sh
+++ b/test/T310-emacs.sh
@@ -1059,7 +1059,6 @@ End of search results.
 === MESSAGES ===
 YYY/notmuch_fail exited with status 1 (see *Notmuch errors* for more details)
 === ERROR ===
-[XXX]
 YYY/notmuch_fail exited with status 1
 command: YYY/notmuch_fail search --format\=sexp --format-version\=4 --sort\=newest-first tag\:inbox
 exit status: 1"
diff --git a/test/T450-emacs-show.sh b/test/T450-emacs-show.sh
index e58124d4..31be55f8 100755
--- a/test/T450-emacs-show.sh
+++ b/test/T450-emacs-show.sh
@@ -191,7 +191,6 @@ test_expect_equal "$(notmuch_emacs_error_sanitize notmuch_fail OUTPUT MESSAGES E
 === MESSAGES ===
 This is an error (see *Notmuch errors* for more details)
 === ERROR ===
-[XXX]
 This is an error
 command: YYY/notmuch_fail show --format\\=sexp --format-version\\=4 --decrypt\\=true --exclude\\=false \\' \\* \\'
 exit status: 1
diff --git a/test/test-lib.sh b/test/test-lib.sh
index c379d140..b669cede 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -502,12 +502,16 @@ print(msg.as_string(False))
 ' "$@"
 }
 
+notmuch_debug_sanitize () {
+    grep -v '^D.:'
+}
+
 notmuch_exception_sanitize () {
     perl -pe 's/(A Xapian exception occurred at .*[.]cc?):([0-9]*)/\1:XXX/'
 }
 
 notmuch_search_sanitize () {
-    perl -pe 's/("?thread"?: ?)("?)................("?)/\1\2XXX\3/'
+    notmuch_debug_sanitize | perl -pe 's/("?thread"?: ?)("?)................("?)/\1\2XXX\3/'
 }
 
 notmuch_search_files_sanitize () {
@@ -523,6 +527,7 @@ notmuch_show_sanitize () {
     sed -e "$NOTMUCH_SHOW_FILENAME_SQUELCH"
 }
 notmuch_show_sanitize_all () {
+    notmuch_debug_sanitize | \
     sed \
 	-e 's| filename:.*| filename:XXXXX|' \
 	-e 's| id:[^ ]* | id:XXXXX |' | \
@@ -545,9 +550,10 @@ notmuch_emacs_error_sanitize () {
     shift
     for file in "$@"; do
 	echo "=== $file ==="
-	cat "$file"
+	notmuch_debug_sanitize < "$file"
     done | sed \
-	-e 's/^\[.*\]$/[XXX]/' \
+	-e '/^$/d' \
+	-e '/^\[.*\]$/d' \
 	-e "s|^\(command: \)\{0,1\}/.*/$command|\1YYY/$command|"
 }
 
@@ -893,7 +899,7 @@ test_C () {
     echo "== stdout ==" > OUTPUT.stdout
     echo "== stderr ==" > OUTPUT.stderr
     ./${exec_file} "$@" 1>>OUTPUT.stdout 2>>OUTPUT.stderr
-    notmuch_dir_sanitize OUTPUT.stdout OUTPUT.stderr | notmuch_exception_sanitize > OUTPUT
+    notmuch_dir_sanitize OUTPUT.stdout OUTPUT.stderr | notmuch_exception_sanitize | notmuch_debug_sanitize > OUTPUT
 }
 
 make_shim () {