diff --git a/.test-conda-env-py3.yml b/.test-conda-env-py3.yml
index b8f649e0a4f0d73e9bf18e0dc1e928a1c7acc6ce..55ccfcd4508f3db9be507374ef172b01f5bb45cb 100644
--- a/.test-conda-env-py3.yml
+++ b/.test-conda-env-py3.yml
@@ -7,7 +7,6 @@ dependencies:
 - python=3
 - git
 - numpy
-- libhwloc=1
 - pocl
 - mako
 - pyopencl
diff --git a/test/test_partition.py b/test/test_partition.py
index 3ca5e3899d632f3e86751d70ec2dad1e2e2c6b07..77e27137d65d62d2fbd8087c743b0238a11029c6 100644
--- a/test/test_partition.py
+++ b/test/test_partition.py
@@ -517,7 +517,9 @@ def test_mpi_communication(num_partitions, order):
     from subprocess import check_call
     import sys
     check_call([
-        "mpiexec", "-np", str(num_ranks),
+        "mpiexec",
+        "--oversubscribe",
+        "-np", str(num_ranks),
         "-x", "RUN_WITHIN_MPI=1",
         "-x", "order=%d" % order,