add gd_diff.py + tests for functions in it.

* gd_diff.py (read_file, get_packages): add functions.
* tests/__init__.py: add file.
* tests/files/pkgs.list: add file.
* tests/test_gd_diff.py: add file.

1 files changed, 39 insertions, 0 deletions

diff --git a/gd_diff.py b/gd_diff.py
new file mode 100644
index 0000000..97cf175
--- /dev/null
+++ b/gd_diff.py
@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+#  This file is part of gns-deb-diff.
+#
+#  gns-deb-diff is under the Public Domain. See
+#  <https://creativecommons.org/publicdomain/zero/1.0>
+
+import sys
+
+# list of recognized fields.
+field_list = [
+    "Change-Type",
+    "Changed-From-Debian",
+]
+
+def read_file(fpath):
+    """Read file `f` and return its content.
+
+    """
+    try:
+        f = open(fpath, 'r')
+    except FileNotFoundError as e:
+        print("Error opening '%s' \n Error Info:\n  %r" % (fpath, e),
+              file=sys.stderr)
+        sys.exit(1)
+
+    return f.read()
+
+
+def get_packages(pkgs_file):
+    """Return an iterator contaning of package names from `pkgs_file`.
+
+    """
+    pkgs = read_file(pkgs_file).split('\n')
+    # sanitize
+    pkgs_iter = map(lambda x: x.strip(), pkgs)
+
+    return pkgs_iter