diff --git a/bypy/init_env.py b/bypy/init_env.py
index 8de214036..e2759adac 100644
--- a/bypy/init_env.py
+++ b/bypy/init_env.py
@@ -62,7 +62,12 @@ def build_c_extensions(ext_dir, args):
 
 
 def run_tests(path_to_kitty, cwd_on_failure):
-    ret = run(PYTHON, 'test.py', cwd=cwd_on_failure)
+    kw = {'cwd': cwd_on_failure}
+    if not ismacos:
+        # this is needed for the spawn test which starts an interpreter
+        # using the kitty launcher.
+        kw['PYTHONHOME'] = PREFIX
+    ret = run(PYTHON, 'test.py', **kw)
     if ret != 0:
         os.chdir(cwd_on_failure)
         print(
diff --git a/kitty_tests/tui.py b/kitty_tests/tui.py
index ca249e023..2a989deb6 100644
--- a/kitty_tests/tui.py
+++ b/kitty_tests/tui.py
@@ -44,6 +44,5 @@ class TestTUI(BaseTest):
         self.assertTrue(le.pending_bell)
 
     def test_multiprocessing_spawn(self):
-        return  # temporarily disable this test till I can figure out why its failing in the build env
         from kitty.multiprocessing import test_spawn
         test_spawn()