diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f0ed00e..76d3a30 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -85,7 +85,7 @@ tests_seq:
     - job: "image:build"
       optional: true
   script:
-    - cp site.cfg.files/site.cfg.docker_seq site.cfg
+    # - cp site.cfg.files/site.cfg.docker_seq site.cfg
     - nox -s "tests(with_cov=True, with_mpi=False)"
 
 
@@ -95,7 +95,7 @@ tests_mpi:
     - job: "image:build"
       optional: true
   script:
-    - cp site.cfg.files/site.cfg.docker_mpi site.cfg
+    # - cp site.cfg.files/site.cfg.docker_mpi site.cfg
     - nox -s "tests(with_cov=True, with_mpi=True)"
 
 
diff --git a/noxfile.py b/noxfile.py
index 294dc7e..ec3645d 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -49,7 +49,11 @@ def tests(session, with_mpi, with_cov):
         command += " -G mpi"
     session.run_always(*command.split(), external=True)
 
-    session.install("-e", ".", "--no-deps", "-v", silent=False)
+    session.install(
+        ".", "--no-deps", "-v",
+        "--config-settings=setup-args=-Dtransonic-backend=python",
+        silent=False,
+    )
     session.run("ls", "src/fluidfft/fft3d", silent=False, external=True)
 
     session.install("-e", "plugins/fluidfft-pyfftw")
@@ -90,7 +94,7 @@ def run_command(command, **kwargs):
 def doc(session):
     session.run_always("pdm", "sync", "-G", "doc", "--no-self", external=True)
     session.install(
-        "-e", ".", "--no-deps", env={"FLUIDFFT_TRANSONIC_BACKEND": "python"}
+        ".", "--no-deps", "--config-settings=setup-args=-Dtransonic-backend=python"
     )
     session.install("-e", "plugins/fluidfft-pyfftw")