Keep tests in json format

So the results are typed
2020-08-24 18:37:55 +02:00
parent d592cc3050
commit 4d280e02b0
55 changed files with 55 additions and 329 deletions
--- a/tests_dir/union_and_select.result
+++ b/tests_dir/union_and_select.result
@@ -1,4 +1 @@
-id,skill
-0,C
-2,C
-4,C
+{"content": [[2, "C"], [0, "C"], [4, "C"]], "header": ["id", "skill"]}