### Question:
FileNames { File getForVersion( long version ) { return new File( baseDirectory, BASE_FILE_NAME + version ); } FileNames( File baseDirectory ); SortedMap<Long,File> getAllFiles( FileSystemAbstraction fileSystem, Log log );  }### Answer:
@Test public void shouldProperlyFormatFilenameForVersion() { File base = new File( "base" ); FileNames fileNames = new FileNames( base ); for ( int i = 0; i < 100; i++ ) { File forVersion = fileNames.getForVersion( i ); assertEquals( forVersion, new File( base, FileNames.BASE_FILE_NAME + i ) ); } }