diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index a4fd9e597f..e143d4e2c5 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -55,7 +55,7 @@ jobs:
       run: |
         conda activate zarr-env
         python -m pip install --upgrade pip
-        python -m pip install -U pip setuptools wheel codecov
+        python -m pip install -U pip setuptools wheel codecov line_profiler
         python -m pip install -rrequirements_dev_minimal.txt numpy${{ matrix.numpy_version}} -rrequirements_dev_optional.txt pymongo redis
         python -m pip install -e . 
         python -m pip freeze
diff --git a/bench/compress_normal.py b/bench/compress_normal.py
index e9b3945f4a..ce0a05b9ec 100644
--- a/bench/compress_normal.py
+++ b/bench/compress_normal.py
@@ -7,34 +7,38 @@
 import zarr
 from zarr import blosc
 
-sys.path.insert(0, '..')
+if __name__ == "__main__":
 
-# setup
-a = np.random.normal(2000, 1000, size=200000000).astype('u2')
-z = zarr.empty_like(a, chunks=1000000, compression='blosc', compression_opts=dict(cname='lz4', clevel=5, shuffle=2))
-print(z)
+    sys.path.insert(0, '..')
 
-print('*' * 79)
+    # setup
+    a = np.random.normal(2000, 1000, size=200000000).astype('u2')
+    z = zarr.empty_like(a, chunks=1000000,
+                        compression='blosc',
+                        compression_opts=dict(cname='lz4', clevel=5, shuffle=2))
+    print(z)
 
-# time
-t = timeit.repeat('z[:] = a', repeat=10, number=1, globals=globals())
-print(t)
-print(min(t))
-print(z)
+    print('*' * 79)
 
-# profile
-profile = line_profiler.LineProfiler(blosc.compress)
-profile.run('z[:] = a')
-profile.print_stats()
+    # time
+    t = timeit.repeat('z[:] = a', repeat=10, number=1, globals=globals())
+    print(t)
+    print(min(t))
+    print(z)
 
-print('*' * 79)
+    # profile
+    profile = line_profiler.LineProfiler(blosc.compress)
+    profile.run('z[:] = a')
+    profile.print_stats()
 
-# time
-t = timeit.repeat('z[:]', repeat=10, number=1, globals=globals())
-print(t)
-print(min(t))
+    print('*' * 79)
 
-# profile
-profile = line_profiler.LineProfiler(blosc.decompress)
-profile.run('z[:]')
-profile.print_stats()
+    # time
+    t = timeit.repeat('z[:]', repeat=10, number=1, globals=globals())
+    print(t)
+    print(min(t))
+
+    # profile
+    profile = line_profiler.LineProfiler(blosc.decompress)
+    profile.run('z[:]')
+    profile.print_stats()
diff --git a/requirements_dev_optional.txt b/requirements_dev_optional.txt
index a0f9bdf7eb..b4f2d8365d 100644
--- a/requirements_dev_optional.txt
+++ b/requirements_dev_optional.txt
@@ -15,7 +15,7 @@ tox==3.23.1
 coverage
 flake8==3.9.2
 pytest-cov==2.12.1
-pytest-doctestplus==0.4.0
+pytest-doctestplus==0.9.0
 h5py==3.2.1
 s3fs==2021.5.0
 fsspec==2021.5.0