Allow Polymorphic persistenence

[JanSchankin]

When DeepSampler wants to deserialize an Object, the concrete type of the object must be known, so that a new instance of that type can be created.

There are two cases where different deserialization approaches are used:

• Serialization and Deserialization is completely done by the underlying persistence framework (Jackson by default)
• Serialization and Deserialization is done using PersistentBeans by DeepSamplers PersistentBeanConverter`.

In the first case type information is completely handled by the persistence framework (Jackson).

In the second case DeepSampler uses the declared return type of the method that is supposed to return the persistent object. Now, there are circumstances where this doesn't work. In general, this is always the case if the actually returned object is a sub type of the declared return type. E.g. in many cases this happens if the declared return type is an interface.

That's why we need to add a type information to PersistentBean in all cases where the original type cannot be determined by the declared return type of the sampled method.

[JanSchankin]

I've added a branch and a first Testcase to accelerate your kickoff:

https://github.com/ppi-ag/deep-sampler/tree/polymorphic-feature

deep-sampler/deepsampler-provider/src/testFixtures/java/de/ppi/deepsampler/provider/common/SamplerAspectTest.java

Line 1201 in 34c07ff

public void polymorphicSamplesCanBeRecordedAndLoaded() throws IOException {

[chb-ppi]

Test fails now

[JanSchankin]

The test was intended to fail until the polymorphic feature is implemented. It should throw an InstantionationError because it is trying to instantiate the interface Animal. Or is it something else? I think the branch is quite old, maybe dev needs to be merged into polymorphic-feature. The test doesn't use PersistentSampler yet.