### Question:
ReportUnitImpl extends ResourceImpl implements ReportUnit,
        ReferenceNormalizer<NormalizationStrategy<? super InputControlsContainer>>, Serializable { @Override public void accept(ResourceVisitor visitor) { super.accept(visitor); Set<ResourceReference> resourceReferences = new HashSet<>(); resourceReferences.add(dataSource); resourceReferences.add(mainReport); resourceReferences.add(query); resourceReferences.addAll(Optional.ofNullable(getInputControls()).orElseGet(ArrayList::new)); resourceReferences.addAll(Optional.ofNullable(getResources()).orElseGet(ArrayList::new)); resourceReferences.stream().filter(Objects::nonNull).forEach(o -> o.accept(visitor)); } ReportUnitImpl(); ResourceReference getDataSource(); void setDataSource(ResourceReference dataSource); void setDataSource(ReportDataSource dataSource); void setDataSourceReference(String referenceURI); ResourceReference getQuery(); void setQuery(ResourceReference query); List getInputControls(); ResourceReference getMainReport(); InputControl getInputControl(String name); void setMainReport(ResourceReference mainReport); void setMainReport(FileResource report); void setMainReportReference(String referenceURI); List getResources(); void setResources(List resources); String getInputControlRenderingView(); String getReportRenderingView(); void setInputControlRenderingView(String viewName); void setReportRenderingView(String viewName); boolean isAlwaysPromptControls(); void setAlwaysPromptControls(boolean alwaysPromptControls); byte getControlsLayout(); void setControlsLayout(byte controlsLayout); void addResource(ResourceReference resourceReference); void addResourceReference(String referenceURI); void addResource(FileResource resource); ResourceReference removeResource(int index); FileResource removeResourceLocal(String name); boolean removeResourceReference(String referenceURI); ValidationResult validate(); void addInputControl(ResourceReference inputControlReference); void addInputControlReference(String referenceURI); void setInputControls(List inputControls); void addInputControl(InputControl inputControl); ResourceReference removeInputControl(int index); InputControl removeInputControlLocal(String name); boolean removeInputControlReference(String referenceURI); void replaceInputControlLocal(String name, ResourceReference inputControlReference); void replaceInputControlReference(String referenceURI, ResourceReference inputControlReference); void replaceInputControlLocal(String name, String newReferenceURI); void replaceInputControlLocal(String name, InputControl inputControl); void replaceInputControlReference(String referenceURI, String newReferenceURI); void replaceInputControlReference(String referenceURI, InputControl inputControl); FileResource getResourceLocal(String name); Long getDataSnapshotId(); void setDataSnapshotId(Long dataSnapshotId); @Override void checkReferences(); @Override Set<ReferenceDescriptor> getDependentReferences(); @Override boolean normalizeReferences(); @Override boolean normalizeReferences(NormalizationStrategy<? super InputControlsContainer> strategy); @Override void accept(ResourceVisitor visitor);  }### Answer:
@Test public void accept_nullDependencies_success() { ReportUnitImpl reportUnit = new ReportUnitImpl(); reportUnit.accept(visitor); verify(visitor, times(1)).visit(reportUnit); }