Method testSetGetDefaultStorageFormat is testing setDefaultStorageFormat
and getDefaultStorageFormat together by setting some value
and verifying it by reading.
Method testSetGetPresentationFigure is testing setPresentationFigure
and getPresentationFigure together by setting some value
and verifying it by reading.
TextAreaFigureContentProducer produces text contents from an existing
TextHolder figure
It can either be specific if set for a specific figure, or generic, encoding
any color passed to the getContents method.