diff --git a/tests/fixtures.py b/tests/fixtures.py
index 8903d02b..db5f06e2 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -15,6 +15,10 @@ import time
 from urllib.parse import unquote
 
 
+# This temp file is used by one of the plugin config tests
+TEMP_PLUGIN_SECRET_FILE = os.path.join(tempfile.gettempdir(), "plugin-secret")
+
+
 class TestResponse:
     def __init__(self, status, headers, body):
         self.status = status
@@ -97,7 +101,6 @@ def make_app_client(
     memory=False,
     config=None,
     filename="fixtures.db",
-    metadata=None,
     is_immutable=False,
     extra_databases=None,
     inspect_data=None,
@@ -140,7 +143,7 @@ def make_app_client(
             immutables=immutables,
             memory=memory,
             cors=cors,
-            metadata=metadata or METADATA,
+            metadata=METADATA,
             plugins_dir=plugins_dir,
             config=config,
             inspect_data=inspect_data,
@@ -247,7 +250,11 @@ METADATA = {
     "source_url": "https://github.com/simonw/datasette/blob/master/tests/fixtures.py",
     "about": "About Datasette",
     "about_url": "https://github.com/simonw/datasette",
-    "plugins": {"name-of-plugin": {"depth": "root"}},
+    "plugins": {
+        "name-of-plugin": {"depth": "root"},
+        "env-plugin": {"foo": {"$env": "FOO_ENV"}},
+        "file-plugin": {"foo": {"$file": TEMP_PLUGIN_SECRET_FILE}},
+    },
     "databases": {
         "fixtures": {
             "description": "Test tables description",
diff --git a/tests/test_plugins.py b/tests/test_plugins.py
index 58e7fe7c..f42eebd7 100644
--- a/tests/test_plugins.py
+++ b/tests/test_plugins.py
@@ -1,5 +1,5 @@
 from bs4 import BeautifulSoup as Soup
-from .fixtures import app_client, make_app_client  # noqa
+from .fixtures import app_client, make_app_client, TEMP_PLUGIN_SECRET_FILE  # noqa
 import base64
 import json
 import os
@@ -126,22 +126,16 @@ def test_plugin_config(app_client):
     assert None is app_client.ds.plugin_config("unknown-plugin")
 
 
-def test_plugin_config_env():
+def test_plugin_config_env(app_client):
     os.environ["FOO_ENV"] = "FROM_ENVIRONMENT"
-    for client in make_app_client(
-        metadata={"plugins": {"env-plugin": {"foo": {"$env": "FOO_ENV"}}}}
-    ):
-        assert {"foo": "FROM_ENVIRONMENT"} == client.ds.plugin_config("env-plugin")
+    assert {"foo": "FROM_ENVIRONMENT"} == app_client.ds.plugin_config("env-plugin")
     del os.environ["FOO_ENV"]
 
 
-def test_plugin_config_file(tmpdir):
-    filepath = str(tmpdir / "secret-file")
-    open(filepath, "w").write("FROM_FILE")
-    for client in make_app_client(
-        metadata={"plugins": {"file-plugin": {"foo": {"$file": filepath}}}}
-    ):
-        assert {"foo": "FROM_FILE"} == client.ds.plugin_config("file-plugin")
+def test_plugin_config_file(app_client):
+    open(TEMP_PLUGIN_SECRET_FILE, "w").write("FROM_FILE")
+    assert {"foo": "FROM_FILE"} == app_client.ds.plugin_config("file-plugin")
+    os.remove(TEMP_PLUGIN_SECRET_FILE)
 
 
 @pytest.mark.parametrize(