add string representation function to SearchAPIWhereFilter #259

- To be used by `NestedWhereFilters` when LHS or RHS has an input of this type

datagateway_api/src/search_api/filters.py

@@ -4,6 +4,8 @@
     PythonICATSkipFilter,
     PythonICATWhereFilter,
 )
+from icat.query import Query
+from icat.client import Client
 
 # TODO - Implement each of these filters for Search API, inheriting from the Python ICAT
 # versions
@@ -17,6 +19,19 @@ def __init__(self, field, value, operation, boolean_operator="and"):
     def apply_filter(self, query):
         return super().apply_filter(query)
 
+    def __str__(self):
+        # TODO - replace with `SessionHandler.client` when that work is merged
+        client = Client("https://localhost.localdomain:8181", checkCert=False)
+        client.login("simple", {"username": "root", "password": "pw"})
+
+        # TODO - can't just hardcode investigation entity. Might need `icat_entity_name`
+        # to be passed into init
+        query = Query(client, "Investigation")
+        query.addConditions(self.create_filter())
+        str_conds = query.get_conditions_as_str()
+
+        return str_conds[0]
+
 
 class SearchAPISkipFilter(PythonICATSkipFilter):
     def __init__(self, skip_value):