raise Error for orphaned containers

[ajtritt]

Problem/Use Case

Currently, orphaned containers i.e. containers with no parent result in a raised warning. This should raise an Error instead.

The relevant code is in pynwb.form.build.map.ObjectMapper.__add_containers:

pynwb/src/pynwb/form/build/map.py

Lines 777 to 783 in f671b8d

	def __add_containers(self, builder, spec, value, build_manager, source, parent_container):
	if isinstance(value, Container):
	if value.parent is None:
	msg = "'%s' (%s) for '%s' (%s)"\
	% (value.name, getattr(value, self.spec.type_key()),
	builder.name, self.spec.data_type_def)
	warnings.warn(msg, OrphanContainerWarning)

This will likely break some tests and will require refactoring some parts of the test suite.

Checklist

• Have you ensured the feature or change was not already reported ?
• Have you included a brief and descriptive title?
• Have you included a clear description of the problem you are trying to solve?
• Have you included a minimal code snippet that reproduces the issue you are encountering?

[oruebel]

@ajtritt @rly can this issue be closed or if not should this be moved to HDMF?