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/config.py

@@ -45,6 +45,27 @@ def defaultenv(baseenv):
     }
 
 
+@pytest.fixture
+def replicaenv(defaultenv):
+    "Default environment for a PostgREST replica."
+    conf = {
+        "PGRST_DB_ANON_ROLE": "postgrest_test_anonymous",
+        "PGRST_DB_SCHEMAS": "replica",
+    }
+    return {
+        "primary": {
+            **defaultenv,
+            **conf,
+        },
+        "replica": {
+            **defaultenv,
+            **conf,
+            "PGHOST": os.environ["PGREPLICAHOST"],
+            "PGREPLICASLOT": os.environ["PGREPLICASLOT"],
+        },
+    }
+
+
 @pytest.fixture
 def slow_schema_cache_env(defaultenv):
     "Slow schema cache load environment PostgREST."

test/io/replica.sql

@@ -0,0 +1,21 @@
+create schema replica;
+
+create or replace function replica.is_replica() returns bool as $$
+  select pg_is_in_recovery();
+$$ language sql;
+
+create or replace function replica.get_replica_slot() returns name as $$
+  select slot_name from pg_replication_slots limit 1;
+$$ language sql;
+
+create table replica.items as select x as id from generate_series(1, 10) x;
+
+DROP ROLE IF EXISTS postgrest_test_anonymous;
+CREATE ROLE postgrest_test_anonymous;
+
+GRANT postgrest_test_anonymous TO :PGUSER;
+
+GRANT USAGE ON SCHEMA replica TO postgrest_test_anonymous;
+
+GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA replica
+TO postgrest_test_anonymous;

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}]'