software/erp5/test: Run tests with ZEO & NEO

Before this patch all ERP5 SlapOS Integration tests only run with ZEO
storage. We should also run them against NEO, because we are using
ERP5 with NEO in SlapOS.

For tests which shouldn't be split into NEO/ZEO flavoured test cases,
this patch adds the '__parameterized__' class attribute, which can
be set to 'False'.

software/erp5/test/test/__init__.py

@@ -27,6 +27,7 @@
 
 import json
 import os
+import sys
 
 from slapos.testing.testcase import makeModuleSetUpAndTestCaseClass
 
@@ -45,9 +46,94 @@ def setUpModule():
   setup_module_executed = True
 
 
-class ERP5InstanceTestCase(SlapOSInstanceTestCase):
+class ERP5InstanceTestMeta(type):
+  """ERP5InstanceTestMeta adjusts instances of ERP5InstanceTestCase to
+     be run in several flavours: with ZEO and with NEO. Adjustment
+     of individual classes can be deactivated by setting the class
+     attribute '__parameterize__' to 'False'.
+  """
+
+  def __new__(cls, name, bases, attrs):
+    base_class = super().__new__(cls, name, bases, attrs)
+    if base_class._isParameterized():
+      cls._parameterize(base_class)
+    return base_class
+
+  # Create two test classes from single definition: e.g. TestX -> TestX_ZEO and TestX_NEO.
+  @classmethod
+  def _parameterize(cls, base_class):
+    test_class_module = sys.modules[base_class.__module__].__dict__
+    for flavour in ("zeo", "neo"):
+      # Override metaclass to avoid infinite loop due to parameterized
+      # class which infinitely creates a parameterized class of itself.
+      class patched(base_class, metaclass=_deactivate):
+        zodb_storage = flavour
+
+      # Switch
+      #   - .getInstanceParameterDict       to ._test_getInstanceParameterDict, and
+      #   - ._base_getInstanceParameterDict to .getInstanceParameterDict
+      # so that we could inject base implementation to be called above user-defined getInstanceParameterDict.
+      # see ERP5InstanceTestCase._base_getInstanceParameterDict for details.
+      patched._test_getInstanceParameterDict = patched.getInstanceParameterDict
+      patched.getInstanceParameterDict       = patched._base_getInstanceParameterDict
+
+      name = "%s_%s" % (base_class.__name__, flavour.upper())
+      test_class_module[name] = type(name, (patched,), dict(patched.__dict__))
+
+  # Hide tests in patched class.
+  # We can't simply call 'delattr', because this wouldn't remove
+  # inherited tests. Overriding dir is sufficient, because this is
+  # the way how unittest discovers tests:
+  #   https://github.com/python/cpython/blob/3.11/Lib/unittest/loader.py#L237
+  def __dir__(self):
+    if self._isParameterized():
+      return [attr for attr in super().__dir__() if not attr.startswith('test')]
+    return super().__dir__()
+
+  def _isParameterized(self):
+    return getattr(self, '__parameterized__', True)
+
+
+class _deactivate(ERP5InstanceTestMeta):
+  """_deactivate behaves exactly the same like plain type.
+
+  It allows the syntax
+
+    >>> class A(metaclass=ERP5InstanceTestMeta): ...
+    >>> class B(A, metaclass=_ERP5InstanceTestMeta): ...
+
+  to deactivate ERP5InstanceTestMeta in a subclass of A.
+  """
+  def __new__(cls, name, bases, attrs):
+    return type.__new__(cls, name, bases, attrs)
+
+  def __dir__(self):
+    return type.__dir__(self)
+
+
+class ERP5InstanceTestCase(SlapOSInstanceTestCase, metaclass=ERP5InstanceTestMeta):
   """ERP5 base test case
   """
+
+  # 20 aren't enough for NEO
+  # https://lab.nexedi.com/nexedi/slapos.core/blob/1.8.4/slapos/testing/testcase.py#L273-274
+  # https://lab.nexedi.com/nexedi/slapos.core/blob/1.8.4/slapos/testing/testcase.py#L379
+  #
+  # instance_max_retry = 100
+
+  # ERP5InstanceTestMeta switches:
+  #   - _base_getInstanceParameterDict to be real getInstanceParameterDict, while
+  #   - test-defined getInstanceParameterDict is switched to _test_getInstanceParameterDict
+  # here we invoke user-defined getInstanceParameterDict and adjust it according to "zodb_storage" parameter.
+  @classmethod
+  def _base_getInstanceParameterDict(cls):
+      try:
+        parameter_dict = json.loads(cls._test_getInstanceParameterDict()["_"])
+      except KeyError:
+        parameter_dict = {}
+      parameter_dict["zodb"] = [{"type": cls.zodb_storage, "server": {}}]
+      return {"_": json.dumps(parameter_dict)}
+
   @classmethod
   def getRootPartitionConnectionParameterDict(cls):
     """Return the output paramters from the root partition"""

software/erp5/test/test/test_erp5.py

@@ -119,6 +119,7 @@ class TestDefaultParameters(ERP5InstanceTestCase, TestPublishedURLIsReachableMix
   """Test ERP5 can be instantiated with no parameters
   """
   __partition_reference__ = 'defp'
+  __parameterize__ = False
 
 
 class TestMedusa(ERP5InstanceTestCase, TestPublishedURLIsReachableMixin):
@@ -310,6 +311,7 @@ class TestZopeNodeParameterOverride(ERP5InstanceTestCase, TestPublishedURLIsReac
   """Test override zope node parameters
   """
   __partition_reference__ = 'override'
+  __parameterize__ = False
 
   @classmethod
   def getInstanceParameterDict(cls):