fix: put special fields first (#1622)

Closes #1620

Sorting the fields prior to putting them in the query string
assures that '_all_' and '_default_' appear first in the field
list, satisfying the criteria of Tableau Server/Cloud to process
those first. Order of other fields appeared to be irrelevant, so
the test simply ensures their presence.

Co-authored-by: Jordan Woods <13803242+jorwoods@users.noreply.github.com>

Author: jorwoods

tableauserverclient/server/request_options.py

@@ -96,7 +96,10 @@ def get_query_params(self) -> dict:
         if self.pagesize:
             params["pageSize"] = self.pagesize
         if self.fields:
-            params["fields"] = ",".join(self.fields)
+            if "_all_" in self.fields:
+                params["fields"] = "_all_"
+            else:
+                params["fields"] = ",".join(sorted(self.fields))
         return params
 
     def page_size(self, page_size):

test/test_request_option.py

@@ -378,3 +378,27 @@ def test_queryset_only_fields(self) -> None:
         loop = self.server.users.only_fields("id")
         assert "id" in loop.request_options.fields
         assert "_default_" not in loop.request_options.fields
+
+    def test_queryset_field_order(self) -> None:
+        with requests_mock.mock() as m:
+            m.get(self.server.views.baseurl, text=SLICING_QUERYSET_PAGE_1.read_text())
+            loop = self.server.views.fields("id", "name")
+            list(loop)
+            history = m.request_history[0]
+
+        fields = history.qs.get("fields", [""])[0].split(",")
+
+        assert fields[0] == "_default_"
+        assert "id" in fields
+        assert "name" in fields
+
+    def test_queryset_field_all(self) -> None:
+        with requests_mock.mock() as m:
+            m.get(self.server.views.baseurl, text=SLICING_QUERYSET_PAGE_1.read_text())
+            loop = self.server.views.fields("id", "name", "_all_")
+            list(loop)
+            history = m.request_history[0]
+
+        fields = history.qs.get("fields", [""])[0]
+
+        assert fields == "_all_"