use pageserver for pg list command

test_runner/test_pageserver_api.py

@@ -1,6 +1,7 @@
 import pytest
 import psycopg2
 import getpass
+import json
 
 pytest_plugins = ("fixtures.zenith_fixtures")
 
@@ -17,3 +18,34 @@ def test_status(zen_simple):
     cur.execute('status;')
     assert cur.fetchone() == ('hello world',)
     pg_conn.close()
+
+def test_pg_list(zen_simple):
+    username = getpass.getuser()
+    page_server_conn_str = 'host={} port={} dbname=postgres user={}'.format(
+        HOST, PAGESERVER_PORT, username)
+    page_server_conn = psycopg2.connect(page_server_conn_str)
+    page_server_conn.autocommit = True
+    page_server_cur = page_server_conn.cursor()
+
+    page_server_cur.execute('pg_list;')
+    branches = json.loads(page_server_cur.fetchone()[0])
+    assert len(branches) == 1
+    assert branches[0]['name'] == 'main'
+    assert 'timeline_id' in branches[0]
+    assert 'latest_valid_lsn' in branches[0]
+
+    zen_simple.zenith_cli.run(['branch', 'experimental', 'main'])
+    zen_simple.zenith_cli.run(['pg', 'create', 'experimental'])
+
+    page_server_cur.execute('pg_list;')
+    new_branches = json.loads(page_server_cur.fetchone()[0])
+    assert len(new_branches) == 2
+    new_branches.sort(key=lambda k: k['name'])
+
+    assert new_branches[0]['name'] == 'experimental'
+    assert new_branches[0]['timeline_id'] != branches[0]['timeline_id']
+
+    # TODO: do the LSNs have to match here?
+    assert new_branches[1] == branches[0]
+
+    page_server_conn.close()