Add type accessors for JSON indexed/pathed element access

Added new accessors to expressions of type :class:`.JSON` to allow for
specific datatype access and comparison, covering strings, integers,
numeric, boolean elements.   This revises the documented approach of
CASTing to string when comparing values, instead adding specific
functionality into the PostgreSQL, SQlite, MySQL dialects to reliably
deliver these basic types in all cases.

The change also delivers a new feature to the test exclusions
system so that combinations and exclusions can be used together.

Fixes: #4276
Change-Id: Ica5a926c060feb40a0a7cd60b9d6e061d7825728

1 files changed, 11 insertions, 0 deletions

diff --git a/test/requirements.py b/test/requirements.py
index 471e68f4c..95b449edb 100644
--- a/test/requirements.py
+++ b/test/requirements.py
@@ -827,6 +827,17 @@ class DefaultRequirements(SuiteRequirements):
             ]
         )
 
+    @property
+    def json_index_supplementary_unicode_element(self):
+        # for sqlite see https://bugs.python.org/issue38749
+        return skip_if(
+            [
+                lambda config: against(config, "mysql")
+                and config.db.dialect._is_mariadb,
+                "sqlite",
+            ]
+        )
+
     def _sqlite_json(self, config):
         if not against(config, "sqlite >= 3.9"):
             return False