[tests] add somewhat experimental import-time tests

add auto-generated tests that check that a given module can be imported,
if all prerequisites are followed.

see #641

tests/modules/contrib/test_kernel.py

@@ -21,4 +21,8 @@ def test_full_text(mocker, kernel_module):
     assert some_kernel == kernel_module.widget().full_text()
 
 
+def test_load_module():
+    __import__("modules.contrib.kernel")
+
+
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