diff --git a/nixos/modules/tests/run-client.py b/nixos/modules/tests/run-client.py
index cdf8ffeb62393c89fc86107bd7e1ffdc8fddfbb5..4b667da71a1cfefbfd59fc14e0547039db9dd893 100755
--- a/nixos/modules/tests/run-client.py
+++ b/nixos/modules/tests/run-client.py
@@ -4,6 +4,7 @@ from os import environ
 from sys import argv
 from shutil import which
 from subprocess import check_output
+from configparser import ConfigParser
 
 def main():
     (introducerFURL,) = argv[1:]
@@ -22,6 +23,18 @@ def main():
         "/tmp/client",
     ])
 
+    # Add necessary ZKAPAuthorizer configuration bits.
+    config = ConfigParser()
+    with open("/tmp/client/tahoe.cfg") as cfg:
+        config.read_file(cfg)
+
+    config.set(u"client", u"storage.plugins", u"privatestorageio-zkapauthz-v1")
+    config.add_section(u"storageclient.plugins.privatestorageio-zkapauthz-v1")
+    config.set(u"storageclient.plugins.privatestorageio-zkapauthz-v1", u"redeemer", u"ristretto")
+
+    with open("/tmp/client/tahoe.cfg", "wt") as cfg:
+        config.write(cfg)
+
     run([
         "daemonize",
         "-o", "/tmp/stdout",