### Question:
PdfDocumentDescriptor { public String getVersionString() { return ofNullable(version).map(PdfVersion::getVersionString).orElse(""); } private  PdfDocumentDescriptor(File file, String password); String getFileName(); PdfFileSource toPdfFileSource(); String getInformation(String key); void setInformationDictionary(Map<String, String> info); void putInformation(String key, String value); void pages(int newValue); ObservableAtomicReference<PdfDescriptorLoadingStatus> loadingStatus(); ObservableAtomicReference<Integer> pages(); void moveStatusTo(PdfDescriptorLoadingStatus destination); String getPassword(); void setPassword(String password); boolean hasPassword(); String getVersionString(); PdfVersion getVersion(); void setVersion(PdfVersion version); File getFile(); void setValidBookmarksLevels(Set<Integer> levels); SortedSet<Integer> getValidBookmarksLevels(); boolean hasReferences(); boolean release(); void releaseAll(); PdfDocumentDescriptor retain(); static PdfDocumentDescriptor newDescriptor(File file, String password); static PdfDocumentDescriptor newDescriptorNoPassword(File file);  }### Answer:
@Test public void noVersionString() { assertEquals("", victim.getVersionString()); }
@Test public void getVersionString() { victim.setVersion(PdfVersion.VERSION_1_5); assertFalse(isBlank(victim.getVersionString())); }