def METHOD_NAME(self):
    loadBlob_calls = []
    blobhelper = self._make_default()
    orig_loadBlobInternal = blobhelper._loadBlobInternal
    def loadBlob_wrapper(cursor, oid, serial, blob_lock):
        fn = orig_loadBlobInternal(cursor, oid, serial, blob_lock)
        if not loadBlob_calls:
            os.remove(fn)
            loadBlob_calls.append(1)
        return fn
    blobhelper._loadBlobInternal = loadBlob_wrapper
    from ZODB.blob import Blob
    from ZODB.blob import BlobFile
    b = Blob()
    with blobhelper.openCommittedBlobFile(None, test_oid, test_tid, b) as f:
        self.assertEqual(loadBlob_calls, [1])
        self.assertEqual(f.__class__, BlobFile)
        self.assertEqual(f.read(), b'blob here')