test: sanity tests for primary and replica

* new --replica option to `postgrest-with-postgresql-*`
* new command `postgrest-test-replica`
* new sanity tests on test_replica.py
* add postgrest-test-replica to postgrest-check and postgrest-coverage

test/io/test_replica.py

@@ -0,0 +1,28 @@
+"IO tests for PostgREST started on replicas"
+
+import pytest
+
+from config import *
+from util import *
+from postgrest import *
+
+
+def test_sanity_replica(replicaenv):
+    "Test that primary and replica are working as intended"
+
+    with run(env=replicaenv["primary"]) as postgrest:
+        response = postgrest.session.get("/rpc/is_replica")
+        assert response.text == "false"
+
+        response = postgrest.session.get("/rpc/get_replica_slot")
+        assert response.text == '"' + replicaenv["replica"]["PGREPLICASLOT"] + '"'
+
+        response = postgrest.session.get("/items?select=count")
+        assert response.text == '[{"count":10}]'
+
+    with run(env=replicaenv["replica"]) as postgrest:
+        response = postgrest.session.get("/rpc/is_replica")
+        assert response.text == "true"
+
+        response = postgrest.session.get("/items?select=count")
+        assert response.text == '[{"count":10}]'