py/objmodule: Implement PEP 562's __getattr__ for modules.

Configurable via MICROPY_MODULE_GETATTR, disabled by default.  Among other
things __getattr__ for modules can help to build lazy loading / code
unloading at runtime.

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/import/module_getattr.py b/tests/import/module_getattr.py
new file mode 100644
index 000000000..4a18f414d
--- /dev/null
+++ b/tests/import/module_getattr.py
@@ -0,0 +1,23 @@
+# test __getattr__ on module
+
+# ensure that does_not_exist doesn't exist to start with
+this = __import__(__name__)
+try:
+    this.does_not_exist
+    assert False
+except AttributeError:
+    pass
+
+# define __getattr__
+def __getattr__(attr):
+    if attr == 'does_not_exist':
+        return False
+    raise AttributeError
+
+# do feature test (will also test functionality if the feature exists)
+if not hasattr(this, 'does_not_exist'):
+    print('SKIP')
+    raise SystemExit
+
+# check that __getattr__ works as expected
+print(this.does_not_exist)