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

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.

1 files changed, 3 insertions, 2 deletions

diff --git a/test/test-lib.sh b/test/test-lib.sh
index c505e764..d2b2a47f 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -450,9 +450,10 @@ 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" "$expected" "$@"