[PATCH] test: Use small Python script for JSON normalization instead of json.tool

[Vladimir Panteleev <notmuch@thecybershadow.net>]

json.tool does not sort or otherwise normalize the order of JSON keys
in its output, which can result in test failures on some test systems.

Instead, use a one-line Python script passed to the interpreter
directly on its command line. Use sort_keys=True for json.dump to
ensure the key order is normalized. The script works with both Python
2 and 3.

* test/test-lib.sh: Update test_expect_equal_json.
---
 test/test-lib.sh | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/test/test-lib.sh b/test/test-lib.sh
index 7ae96c69..d720bb69 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -627,9 +627,10 @@ test_expect_equal_json () {
     # The test suite forces LC_ALL=C, but this causes Python 3 to
     # decode stdin as ASCII.  We need to read JSON in UTF-8, so
     # override Python's stdio encoding defaults.
-    output=$(echo "$1" | PYTHONIOENCODING=utf-8 $NOTMUCH_PYTHON -mjson.tool \
+    local script='import json, sys; json.dump(json.load(sys.stdin), sys.stdout, sort_keys=True, indent=4)'
+    output=$(echo "$1" | PYTHONIOENCODING=utf-8 $NOTMUCH_PYTHON -c "$script" \
         || echo "$1")
-    expected=$(echo "$2" | PYTHONIOENCODING=utf-8 $NOTMUCH_PYTHON -mjson.tool \
+    expected=$(echo "$2" | PYTHONIOENCODING=utf-8 $NOTMUCH_PYTHON -c "$script" \
         || echo "$2")
     shift 2
     test_expect_equal "$output" "$expected" "$@"
-- 
2.13.3