### Question:
B2FileContentSource implements B2ContentSource { @Override public InputStream createInputStream() throws IOException { return new FileInputStream(source); } private  B2FileContentSource(File source,
                                String sha1); static Builder builder(File source); static B2FileContentSource build(File source); @Override String getSha1OrNull(); @Override Long getSrcLastModifiedMillisOrNull(); @Override long getContentLength(); @Override InputStream createInputStream();  }### Answer:
@Test public void testCreateInputStreamTriesToOpenTheFile() throws IOException, B2Exception { thrown.expect(FileNotFoundException.class); thrown.expectMessage(file + " (No such file or directory)"); contentSource.createInputStream(); }