Add the 1st lettuce test for the basic replication.

Basically check that the table inserted on the primary
will get its way to the secondary.

features/basic_replication.py

@@ -0,0 +1,41 @@
+import psycopg2 as pg
+from time import sleep
+
+from lettuce import world, steps
+
+PATRONI_CONFIG = '{}.yml'
+
+
+@steps
+class BasicReplicationSteps(object):
+
+    def __init__(self, environ):
+        self.env = environ
+        self.processes = {}
+        self.connstring = {}
+        self.cwd = None
+        self.max_replication_delay = 10
+
+    def start_patroni(self, step, pg_name):
+        '''I have started (\w+)'''
+        return world.pctl.start_patroni(pg_name)
+
+    def add_table(self, step, table_name, pg_name):
+        '''I add the table (\w+) to (\w+)'''
+        # parse the configuration file and get the port
+        try:
+            world.pctl.query(pg_name, "CREATE TABLE {0}()".format(table_name))
+        except pg.Error as e:
+            assert False, "Error creating table {0} on {1}: {2}".format(table_name, pg_name, e)
+
+    def table_is_present_on(self, step, table_name, pg_name):
+        '''Then table (\w+) is present on (\w+)'''
+        for i in range(self.max_replication_delay):
+            if world.pctl.query(pg_name, "SELECT 1 FROM {0}".format(table_name), fail_ok=True) is not None:
+                break
+            sleep(1)
+        else:
+            assert False,\
+                "Table {0} is not present on {1} after {2} seconds".format(table_name, pg_name, self.max_replication_delay)
+
+BasicReplicationSteps(world)