diff --git a/pkgs/sage-conf/.gitignore b/pkgs/sage-conf/.gitignore
index 2f96201a1c9..2fff1627b9f 100644
--- a/pkgs/sage-conf/.gitignore
+++ b/pkgs/sage-conf/.gitignore
@@ -1,5 +1,4 @@
 /_sage_conf/_conf.py
-/setup.cfg
 /build
 /dist
 /*.egg-info
diff --git a/pkgs/sage-conf_pypi/sage_root/.upstream.d b/pkgs/sage-conf_pypi/sage_root/.upstream.d
new file mode 120000
index 00000000000..243d6b8c910
--- /dev/null
+++ b/pkgs/sage-conf_pypi/sage_root/.upstream.d
@@ -0,0 +1 @@
+../../../.upstream.d
\ No newline at end of file
diff --git a/pkgs/sage-conf_pypi/setup.py b/pkgs/sage-conf_pypi/setup.py
index ac2b5fb3192..5a8240b6e9d 100644
--- a/pkgs/sage-conf_pypi/setup.py
+++ b/pkgs/sage-conf_pypi/setup.py
@@ -36,14 +36,14 @@ def run(self):
         if os.environ.get('CONDA_PREFIX', ''):
             SETENV = ':'
         else:
-            SETENV = '(. ./.homebrew-build-env 2> /dev/null || :)'
+            SETENV = '. ./.homebrew-build-env 2> /dev/null'
 
         SAGE_LOCAL = os.path.join(SAGE_ROOT, 'local')
 
         if os.path.exists(os.path.join(SAGE_ROOT, 'config.status')):
             print(f'Reusing configured SAGE_ROOT={SAGE_ROOT}')
         else:
-            cmd = f"cd {SAGE_ROOT} && {SETENV} && ./configure --prefix={SAGE_LOCAL} --with-python={sys.executable} --enable-build-as-root --enable-download-from-upstream-url --with-system-python3=force --with-sage-venv --disable-notebook --disable-sagelib --disable-sage_conf --disable-doc"
+            cmd = f"cd {SAGE_ROOT} && ({SETENV}; ./configure --prefix={SAGE_LOCAL} --with-python={sys.executable} --enable-build-as-root --enable-download-from-upstream-url --with-system-python3=force --with-sage-venv --disable-notebook --disable-sagelib --disable-sage_conf --disable-doc)"
             print(f"Running {cmd}")
             sys.stdout.flush()
             if os.system(cmd) != 0:
@@ -73,10 +73,10 @@ def run(self):
         # (that use native libraries shared with other packages).
         SETMAKE = 'if [ -z "$MAKE" ]; then export MAKE="make -j$(PATH=build/bin:$PATH build/bin/sage-build-num-threads | cut -d" " -f 2)"; fi'
         TARGETS = 'build'
-        cmd = f'cd {SAGE_ROOT} && {SETENV} && {SETMAKE} && $MAKE V=0 {TARGETS}'
+        cmd = f'cd {SAGE_ROOT} && ({SETENV}; {SETMAKE} && $MAKE V=0 ${{SAGE_CONF_TARGETS-{TARGETS}}})'
         print(f"Running {cmd}", flush=True)
         if os.system(cmd) != 0:
-            raise DistutilsSetupError(f"make {TARGETS} failed")
+            raise SetupError(f"make ${{SAGE_CONF_TARGETS-{TARGETS}}} failed")
 
         setuptools_build_py.run(self)
 
diff --git a/pkgs/sage-conf_pypi/tox.ini b/pkgs/sage-conf_pypi/tox.ini
index b530bd10554..fadf9a9cc6c 100644
--- a/pkgs/sage-conf_pypi/tox.ini
+++ b/pkgs/sage-conf_pypi/tox.ini
@@ -1,12 +1,49 @@
 [tox]
-envlist = python
+envlist = py39, py310, py311, py39-user, py310-user, py311-user
 
-[testenv]
+[testenv:.pkg]
+basepython = py311
 passenv =
    MAKE
+   # So that .homebrew-build-env will work
+   HOMEBREW
 
 setenv =
-   HOME={envdir}
+   HOME={work_dir}/home
+   # Passed to 'make' instead of 'build'. We test here:
+   # - frobby (standalone program with dependency on gmp; tests that .homebrew-build-env is invoked correctly)
+   # - lrcalc_python (builds a platform wheel, possibly with use of system library)
+   # - coxeter3 (which allows us to build sagemath-coxeter3)
+   SAGE_CONF_TARGETS=frobby lrcalc_python coxeter3
 
+[testenv:python]
+package = wheel
+deps =
+    # For the 'sage' script
+    sagemath-environment
+setenv =
+    HOME={work_dir}/home
+allowlist_externals =
+   bash
+   env
+commands =
+   bash -c 'set -ex; eval $SETENV; \
+            sage-config; \
+            ls $(sage-config SAGE_SPKG_WHEELS); \
+            sage -sh -c "frobby genideal"; \
+            {envpython} -m pip install $(sage-config SAGE_SPKG_WHEELS)/*.whl'
+
+[testenv:python-user]
+package = wheel
+deps =
+    {[testenv:python]deps}
+setenv =
+    {[testenv:python]setenv}
+    PYTHONUSERBASE={work_dir}/userbase
+    SETENV=export PATH={env:PYTHONUSERBASE}/bin:{env:PATH}
+system_site_packages = True
+install_command = env PATH={env:PYTHONUSERBASE}/bin:{env_bin_dir} python -I -m pip install --user {opts} {packages}
+allowlist_externals =
+   {[testenv:python]allowlist_externals}
 commands =
-   sage-config
+   {[testenv:python]commands}