Allow most of the async tests to pass on CockroachDB

Added function to get crdb version from a connection

tests/test_async.py

@@ -33,7 +33,8 @@ import psycopg2
 import psycopg2.errors
 from psycopg2 import extensions as ext
 
-from .testutils import ConnectingTestCase, StringIO, skip_before_postgres, slow
+from .testutils import (ConnectingTestCase, StringIO, skip_before_postgres,
+    crdb_version, slow)
 
 
 class PollableStub(object):
@@ -62,6 +63,10 @@ class AsyncTests(ConnectingTestCase):
         self.wait(self.conn)
 
         curs = self.conn.cursor()
+        if crdb_version(self.sync_conn) is not None:
+            curs.execute("set experimental_enable_temp_tables = 'on'")
+            self.wait(curs)
+
         curs.execute('''
             CREATE TEMPORARY TABLE table1 (
               id int PRIMARY KEY

tests/testutils.py

@@ -407,6 +407,38 @@ def skip_if_windows(cls):
     return decorator(cls)
 
 
+def crdb_version(conn, __crdb_version=[]):
+    """
+    Return the CockroachDB version if that's the db testing, else None.
+
+    Return the number as an integer similar to PQserverVersion: return
+    v20.1.3 as 200103.
+
+    Assume all the connections are on the same db: return a chached result on
+    following runs.
+
+    """
+    if __crdb_version:
+        return __crdb_version[0]
+
+    with conn.cursor() as cur:
+        try:
+            cur.execute("show crdb_version")
+        except psycopg2.ProgrammingError:
+            __crdb_version.append(None)
+        else:
+            sver = cur.fetchone()[0]
+            m = re.search(r"\bv(\d+)\.(\d+)\.(\d+)", sver)
+            if not m:
+                raise ValueError(
+                    "can't parse CockroachDB version from %s" % sver)
+
+            ver = int(m.group(1)) * 10000 + int(m.group(2)) * 100 + int(m.group(3))
+            __crdb_version.append(ver)
+
+    return __crdb_version[0]
+
+
 class py3_raises_typeerror(object):
     def __enter__(self):
         pass