Consume FIDO result as CSV and make assertions

Bring in a CSV reader to consume the FIDO output and make various
assertions about the result's validity.

tests/test_fido.py

@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 from __future__ import print_function
 
+import csv
 import io
 from time import sleep
 
@@ -11,6 +12,12 @@
 # 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()
@@ -19,9 +26,9 @@ def test_perf_timer():
     assert duration > 0
 
 
-def test_file_identification(tmp_path):
+def test_file_identification(tmp_path, capsys):
     """Reference for Fido-based format identification
-        1. Create a byte-stream with a known magic number and serialise to tempfile.
+        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.
@@ -33,16 +40,39 @@ def test_file_identification(tmp_path):
     f = fido.Fido()
     f.identify_file(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():
+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"