diff --git a/tests/test_config.py b/tests/test_config.py
index 62aea03fb5ad47d3891eafbd811cb42e21de0dfd..465468b5403dea9025287f6916fe8c606e242681 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -17,8 +17,37 @@
 import contextlib
 import os
 
+import pytest
+
+from . import testutil
+
 from conservancy_beancount import config as config_mod
 
+RT_ENV_KEYS = (
+    'RTSERVER',
+    'RTUSER',
+    'RTPASSWD',
+    'RTAUTH',
+)
+
+RT_ENV_CREDS = (
+    'https://example.org/envrt',
+    'envuser',
+    'env  password',
+    'gssapi',
+)
+
+RT_FILE_CREDS = (
+    'https://example.org/filert',
+    'fileuser',
+    'file  password',
+    'basic',
+)
+
+@pytest.fixture
+def rt_environ():
+    return dict(zip(RT_ENV_KEYS, RT_ENV_CREDS))
+
 def _update_environ(updates):
     for key, value in updates.items():
         if value is None:
@@ -41,3 +70,42 @@ def test_repository_from_environment():
 def test_no_repository():
     config = config_mod.Config()
     assert config.repository_path() is None
+
+def test_no_rt_credentials():
+    with update_environ(HOME=testutil.TESTS_DIR):
+        config = config_mod.Config()
+        rt_credentials = config.rt_credentials()
+    assert rt_credentials.server is None
+    assert rt_credentials.user is None
+    assert rt_credentials.passwd is None
+    assert rt_credentials.auth == 'rt'
+
+def test_rt_credentials_from_file():
+    config = config_mod.Config()
+    rt_credentials = config.rt_credentials()
+    assert rt_credentials == RT_FILE_CREDS
+
+def test_rt_credentials_from_environment(rt_environ):
+    with update_environ(**rt_environ):
+        config = config_mod.Config()
+        rt_credentials = config.rt_credentials()
+    assert rt_credentials == RT_ENV_CREDS
+
+@pytest.mark.parametrize('index,drop_key', enumerate(RT_ENV_KEYS))
+def test_rt_credentials_from_file_and_environment_mixed(rt_environ, index, drop_key):
+    del rt_environ[drop_key]
+    with update_environ(**rt_environ):
+        config = config_mod.Config()
+        rt_credentials = config.rt_credentials()
+    expected = list(RT_ENV_CREDS)
+    expected[index] = RT_FILE_CREDS[index]
+    assert rt_credentials == tuple(expected)
+
+def test_rt_credentials_from_all_sources_mixed(tmp_path):
+    server = 'https://example.org/mixedrt'
+    with (tmp_path / '.rtrc').open('w') as rtrc_file:
+        print('user basemix', 'passwd mixed up', file=rtrc_file, sep='\n')
+    with update_environ(HOME=tmp_path, RTSERVER=server, RTUSER='mixedup'):
+        config = config_mod.Config()
+        rt_credentials = config.rt_credentials()
+    assert rt_credentials == (server, 'mixedup', 'mixed up', 'rt')