JsonHelperDataLoadTests is not included in the test suites

[pcdavid]

When trying to convert the project into a plain Maven module (#37), the basic JUnit behavior is to run all the tests, not just the ones included in the two test suites explicitly configured in the current POM. This includes the JsonHelperDataLoadTests, which seems not be included in any of the suites.

Running it reveals that it is currently broken with:

[ERROR] Errors: 
[ERROR]   JsonHelperDataLoadTests.testChangeAttributeTypeMono:65->AbstractEMFJsonTests.testLoad:191->AbstractEMFJsonTests.getModelResource:242->AbstractEMFJsonTests.loadResource:306 » NullPointer Cannot invoke "org.eclipse.sirius.emfjson.resource.JsonResource$IJsonResourceProcessor.getValue(org.eclipse.emf.ecore.EObject, org.eclipse.emf.ecore.EStructuralFeature, Object)" because "this.jsonResourceProcessor" is null
[ERROR]   JsonHelperDataLoadTests.testChangeAttributeTypeMulti:85->AbstractEMFJsonTests.testLoad:191->AbstractEMFJsonTests.getModelResource:242->AbstractEMFJsonTests.loadResource:306 » NullPointer Cannot invoke "org.eclipse.sirius.emfjson.resource.JsonResource$IJsonResourceProcessor.getValue(org.eclipse.emf.ecore.EObject, org.eclipse.emf.ecore.EStructuralFeature, Object)" because "this.jsonResourceProcessor" is null
[ERROR]   JsonHelperDataLoadTests.testChangeAttributeValueMono:106->AbstractEMFJsonTests.testLoad:191->AbstractEMFJsonTests.getModelResource:242->AbstractEMFJsonTests.loadResource:306 » NullPointer Cannot invoke "org.eclipse.sirius.emfjson.resource.JsonResource$IJsonResourceProcessor.getValue(org.eclipse.emf.ecore.EObject, org.eclipse.emf.ecore.EStructuralFeature, Object)" because "this.jsonResourceProcessor" is null
[ERROR]   JsonHelperDataLoadTests.testChangeAttributeValueMulti:126->AbstractEMFJsonTests.testLoad:191->AbstractEMFJsonTests.getModelResource:242->AbstractEMFJsonTests.loadResource:306 » NullPointer Cannot invoke "org.eclipse.sirius.emfjson.resource.JsonResource$IJsonResourceProcessor.getValue(org.eclipse.emf.ecore.EObject, org.eclipse.emf.ecore.EStructuralFeature, Object)" because "this.jsonResourceProcessor" is null