1 files changed, 20 insertions, 7 deletions
diff --git a/tests/shell/helpers/json-pretty.sh b/tests/shell/helpers/json-pretty.sh
index 0d6972b8..5407a842 100755
--- a/tests/shell/helpers/json-pretty.sh
+++ b/tests/shell/helpers/json-pretty.sh
@@ -1,17 +1,30 @@
 #!/bin/bash -e
 
-# WARNING: the output is not guaranteed to be stable.
+exec_pretty() {
+	# The output of this command must be stable (and `jq` and python
+	# fallback must generate the same output.
 
-if command -v jq &>/dev/null ; then
-	# If we have, use `jq`
-	exec jq
-fi
+	if command -v jq &>/dev/null ; then
+		# If we have, use `jq`
+		exec jq
+	fi
 
-# Fallback to python.
-exec python -c '
+	# Fallback to python.
+	exec python -c '
 import json
 import sys
 
 parsed = json.load(sys.stdin)
 print(json.dumps(parsed, indent=2))
 '
+}
+
+[ "$#" -le 1 ] || { echo "At most one argument supported" ; exit 1 ; }
+
+if [ "$#" -eq 1 ] ; then
+	# One argument passed. This must be a JSON file.
+	[ -f "$1" ] || { echo "File \"$1\" does not exist" ; exit 1 ; }
+	exec_pretty < "$1"
+fi
+
+exec_pretty