FIX: Develop out FIDO tests with pytest

fido/fido.py

@@ -532,10 +532,11 @@ def blocking_read(self, file, bytes_to_read):
         buffer = b''
         while bytes_read < bytes_to_read:
             readbuffer = file.read(bytes_to_read - bytes_read)
+            last_read_len = len(readbuffer)
             buffer += readbuffer
-            bytes_read = len(buffer)
-            # break out if EOF is reached.
-            if readbuffer == '':
+            bytes_read += last_read_len
+            # break out if EOF is reached, that is zero bytes read.
+            if last_read_len < 1:
                 break
         return buffer
 

tests/test_fido.py

@@ -1,13 +1,78 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
+from __future__ import print_function
 
+import csv
+import io
 from time import sleep
 
+from fido import fido
 from fido.fido import PerfTimer
 
+# Magic number for fmt/1000.
+MAGIC = b"\x5A\x58\x54\x61\x70\x65\x21\x1A\x01"
+
+# Expected positive PUID.
+PUID = "fmt/1000"
+
+# Expected result.
+OK = "OK"
+
 
 def test_perf_timer():
     timer = PerfTimer()
     sleep(3.6)
     duration = timer.duration()
     assert duration > 0
+
+
+def test_file_identification(tmp_path, capsys):
+    """Reference for Fido-based format identification
+        1. Create a byte-stream with a known magic number and serialize to tempfile.
+        2. Call identify_file(...) to identify the file against Fido's known formats.
+    """
+    # Create a temporary file and write our skeleton file out to it.
+    tmp_file = tmp_path / "tmp_file"
+    tmp_file.write_bytes(MAGIC)
+
+    # Create a Fido instance and call identify_file. The identify_file function
+    # will create and manage a file for itself.
+    f = fido.Fido()
+    f.identify_file(str(tmp_file))
+
+    # Capture the stdout returned by Fido and make assertions about its
+    # validity.
+    captured = capsys.readouterr()
+    assert captured.err == ""
+    reader = csv.reader(io.StringIO(captured.out), delimiter=",")
+    assert reader is not None
+    row = next(reader)
+    assert row[0] == OK, "row hasn't returned a positive identification"
+    assert row[2] == PUID, "row doesn't contain expected PUID value"
+    assert int(row[5]) == len(MAGIC), "row doesn't contain stream length"
+
+
+def test_stream_identification(capsys):
+    """Reference for Fido-based format identification
+        1. Create a byte-stream with a known magic number.
+        2. Call identify_stream(...) to identify the file against Fido's known formats.
+    """
+    # Create the stream object with the known magic-number.
+    fstream = io.BytesIO(MAGIC)
+
+    # Create a Fido instance and call identify_stream. The identify_stream function
+    # will work on the stream as-is. This could be an open file handle that the
+    # caller is managing for itself.
+    f = fido.Fido()
+    f.identify_stream(fstream, "filename to display", extension=False)
+
+    # Capture the stdout returned by Fido and make assertions about its
+    # validity.
+    captured = capsys.readouterr()
+    assert captured.err == ""
+    reader = csv.reader(io.StringIO(captured.out), delimiter=",")
+    assert reader is not None
+    row = next(reader)
+    assert row[0] == OK, "row hasn't returned a positive identification"
+    assert row[2] == PUID, "row doesn't contain expected PUID value"
+    assert int(row[5]) == len(MAGIC), "row doesn't contain stream length"