test: remove thread-unsafe assertions for concurrent tests

Author: olavloite

tests/unit/test_spanner.py

@@ -333,6 +333,7 @@ def _read_helper(
         count=0,
         partition=None,
         directed_read_options=None,
+        concurrent=False,
     ):
         VALUES = [["bharney", 31], ["phred", 32]]
         VALUE_PBS = [[_make_value_pb(item) for item in row] for row in VALUES]
@@ -359,7 +360,8 @@ def _read_helper(
             result_sets[i].values.extend(VALUE_PBS[i])
 
         api.streaming_read.return_value = _MockIterator(*result_sets)
-        transaction._read_request_count = count
+        if not concurrent:
+            transaction._read_request_count = count
 
         if partition is not None:  # 'limit' and 'partition' incompatible
             result_set = transaction.read(
@@ -386,7 +388,8 @@ def _read_helper(
                 directed_read_options=directed_read_options,
             )
 
-        self.assertEqual(transaction._read_request_count, count + 1)
+        if not concurrent:
+            self.assertEqual(transaction._read_request_count, count + 1)
 
         self.assertEqual(list(result_set), VALUES)
         self.assertEqual(result_set.metadata, metadata_pb)
@@ -1105,13 +1108,13 @@ def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_
         threads.append(
             threading.Thread(
                 target=self._read_helper,
-                kwargs={"transaction": transaction, "api": api},
+                kwargs={"transaction": transaction, "api": api, "concurrent": True},
             )
         )
         threads.append(
             threading.Thread(
                 target=self._read_helper,
-                kwargs={"transaction": transaction, "api": api},
+                kwargs={"transaction": transaction, "api": api, "concurrent": True},
             )
         )
         for thread in threads: