diff --git a/t/README b/t/README
index 52c77ae936..9952261299 100644
--- a/t/README
+++ b/t/README
@@ -82,6 +82,12 @@ appropriately before running "make".
 	numbers matching <pattern>.  The number matched against is
 	simply the running count of the test within the file.
 
+-x::
+	Turn on shell tracing (i.e., `set -x`) during the tests
+	themselves. Implies `--verbose`. Note that this can cause
+	failures in some tests which redirect and test the
+	output of shell functions. Use with caution.
+
 -d::
 --debug::
 	This may help the person who is developing a new test.
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 0f4a67bfc6..cf19339cce 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -233,6 +233,10 @@ do
 	--root=*)
 		root=$(expr "z$1" : 'z[^=]*=\(.*\)')
 		shift ;;
+	-x)
+		trace=t
+		verbose=t
+		shift ;;
 	*)
 		echo "error: unknown test option '$1'" >&2; exit 1 ;;
 	esac
@@ -517,10 +521,39 @@ maybe_setup_valgrind () {
 	fi
 }
 
+# This is a separate function because some tests use
+# "return" to end a test_expect_success block early
+# (and we want to make sure we run any cleanup like
+# "set +x").
+test_eval_inner_ () {
+	# Do not add anything extra (including LF) after '$*'
+	eval "
+		test \"$trace\" = t && set -x
+		$*"
+}
+
 test_eval_ () {
-	# This is a separate function because some tests use
-	# "return" to end a test_expect_success block early.
-	eval </dev/null >&3 2>&4 "$*"
+	# We run this block with stderr redirected to avoid extra cruft
+	# during a "-x" trace. Once in "set -x" mode, we cannot prevent
+	# the shell from printing the "set +x" to turn it off (nor the saving
+	# of $? before that). But we can make sure that the output goes to
+	# /dev/null.
+	#
+	# The test itself is run with stderr put back to &4 (so either to
+	# /dev/null, or to the original stderr if --verbose was used).
+	{
+		test_eval_inner_ "$@" </dev/null >&3 2>&4
+		test_eval_ret_=$?
+		if test "$trace" = t
+		then
+			set +x
+			if test "$test_eval_ret_" != 0
+			then
+				say_color error >&4 "error: last command exited with \$?=$test_eval_ret_"
+			fi
+		fi
+	} 2>/dev/null
+	return $test_eval_ret_
 }
 
 test_run_ () {
@@ -531,7 +564,8 @@ test_run_ () {
 	eval_ret=$?
 	teardown_malloc_check
 
-	if test -z "$immediate" || test $eval_ret = 0 || test -n "$expecting_failure"
+	if test -z "$immediate" || test $eval_ret = 0 ||
+	   test -n "$expecting_failure" && test "$test_cleanup" != ":"
 	then
 		setup_malloc_check
 		test_eval_ "$test_cleanup"