diff --git a/src/python/magnum/platform/CMakeLists.txt b/src/python/magnum/platform/CMakeLists.txt
index 861e85e..988f478 100644
--- a/src/python/magnum/platform/CMakeLists.txt
+++ b/src/python/magnum/platform/CMakeLists.txt
@@ -79,5 +79,9 @@ if(NOT MAGNUM_BUILD_STATIC)
     endif()
 endif()
 
+# Not named __init__.py so this directory is not treated as a module by python
+# when running python -m unittest in the parent directory (because numpy uses
+# python's builtin platform module to check for PyPy and it's all downhill from
+# there)
 file(GENERATE OUTPUT ${output_dir}/magnum/platform/__init__.py
-    INPUT ${CMAKE_CURRENT_SOURCE_DIR}/__init__.py)
+    INPUT ${CMAKE_CURRENT_SOURCE_DIR}/_init.py)
diff --git a/src/python/magnum/platform/__init__.py b/src/python/magnum/platform/_init.py
similarity index 100%
rename from src/python/magnum/platform/__init__.py
rename to src/python/magnum/platform/_init.py