Added docs and test for check_url_file()

securedrop/source_app/utils.py

@@ -116,6 +116,11 @@ def normalize_timestamps(filesystem_id):
 
 
 def check_url_file(path, regexp):
+    """
+    Check that a file exists at the path given and contains a single line
+    matching the regexp. Used for checking the source interface address
+    files at /var/lib/securedrop/source_{v2,v3}_url.
+    """
     try:
         f = open(path, "r")
         contents = f.readline().strip()

securedrop/tests/test_source_utils.py

@@ -0,0 +1,30 @@
+import os
+
+from source_app.utils import check_url_file
+# -*- coding: utf-8 -*-
+
+
+def test_check_url_file(config):
+
+    assert check_url_file("nosuchfile", "whatever") is None
+
+    try:
+        def write_url_file(path, content):
+            url_file = open(path, "w")
+            url_file.write("{}\n".format(content))
+
+        url_path = "test_source_url"
+
+        onion_test_url = "abcdabcdabcdabcd.onion"
+        write_url_file(url_path, onion_test_url)
+        assert check_url_file(url_path, r"^[a-z0-9]{16}\.onion$") == onion_test_url
+
+        onion_test_url = "abcdefghabcdefghabcdefghabcdefghabcdefghabcdefghabcdefgh.onion"
+        write_url_file(url_path, onion_test_url)
+        assert check_url_file(url_path, r"^[a-z0-9]{56}\.onion$") == onion_test_url
+
+        write_url_file(url_path, "NO.onion")
+        assert check_url_file(url_path, r"^[a-z0-9]{56}\.onion$") is None
+    finally:
+        if os.path.exists(url_path):
+            os.unlink(url_path)