### Question:
DLCheckpointStore implements CheckpointStore { @Override public boolean fileExists(String filePath) throws IOException { return namespace.logExists(filePath); } DLCheckpointStore(Namespace namespace); @Override List<String> listFiles(String filePath); @Override boolean fileExists(String filePath); @Override long getFileLength(String filePath); @Override InputStream openInputStream(String filePath); @Override OutputStream openOutputStream(String filePath); @Override void rename(String srcLog, String dstLog); @Override void deleteRecursively(String srcPath); @Override void delete(String srcPath); @Override void createDirectories(String srcPath); @Override void close();  }### Answer:
@Test public void testFileExists() throws Exception { namespace.createLog(runtime.getMethodName() + "/test"); assertTrue(store.fileExists(runtime.getMethodName() + "/test")); assertFalse(store.fileExists(runtime.getMethodName() + "/test2")); }