From e0079a537f3a22822e7794154ca98ae17211324796a8915ed9267967b37b82ba Mon Sep 17 00:00:00 2001
From: f4lco <github@falcoduersch.com>
Date: Sat, 28 Mar 2020 21:12:17 +0100
Subject: [PATCH] Support empty menu response

In recent weeks many API calls return "null".
Instead of letting the request fail, the parser
now treats "null" as empty menu.
---
 stw_potsdam/feed.py                   |  5 +++--
 tests/resources/empty.json            |  1 +
 tests/resources/empty_menu_output.xml |  4 ++++
 tests/test_consistency.py             | 28 +++++++++++++++------------
 4 files changed, 24 insertions(+), 14 deletions(-)
 create mode 100644 tests/resources/empty.json
 create mode 100644 tests/resources/empty_menu_output.xml

diff --git a/stw_potsdam/feed.py b/stw_potsdam/feed.py
index d5d6803..35e1acf 100644
--- a/stw_potsdam/feed.py
+++ b/stw_potsdam/feed.py
@@ -58,8 +58,9 @@ def render_menu(menu):
     """
     builder = LazyBuilder()
 
-    for day in _active_days(menu):
-        _process_day(builder, day)
+    if menu:
+        for day in _active_days(menu):
+            _process_day(builder, day)
 
     return builder.toXMLFeed()
 
diff --git a/tests/resources/empty.json b/tests/resources/empty.json
new file mode 100644
index 0000000..d5bca82
--- /dev/null
+++ b/tests/resources/empty.json
@@ -0,0 +1 @@
+null
\ No newline at end of file
diff --git a/tests/resources/empty_menu_output.xml b/tests/resources/empty_menu_output.xml
new file mode 100644
index 0000000..5e6c19b
--- /dev/null
+++ b/tests/resources/empty_menu_output.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<openmensa version="2.1" xmlns="http://openmensa.org/open-mensa-v2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://openmensa.org/open-mensa-v2 http://openmensa.org/open-mensa-v2.xsd">
+  <canteen/>
+</openmensa>
diff --git a/tests/test_consistency.py b/tests/test_consistency.py
index 9afa76c..efb155f 100644
--- a/tests/test_consistency.py
+++ b/tests/test_consistency.py
@@ -16,18 +16,13 @@ def _canteen():
     return read_canteen_config()['griebnitzsee']
 
 
-def _menu():
-    with open(_resource_path('input.json')) as menu_file:
+def _read_menu(resource_name):
+    with open(_resource_path(resource_name)) as menu_file:
         return json.load(menu_file)
 
 
-def _expected_meta_feed():
-    with io.open(_resource_path('meta_output.xml'), encoding='utf-8') as xml:
-        return xml.read()
-
-
-def _expected_menu_feed():
-    with io.open(_resource_path('menu_output.xml'), encoding='utf-8') as xml:
+def _read_feed(resource_name):
+    with io.open(_resource_path(resource_name), encoding='utf-8') as xml:
         return xml.read()
 
 
@@ -37,14 +32,23 @@ def test_meta_consistency():
 
     actual = feed.render_meta(canteen, menu_feed_url)
 
-    expected = _expected_meta_feed()
+    expected = _read_feed('meta_output.xml')
     assert expected == actual
 
 
 def test_menu_consistency():
-    menu = _menu()
+    menu = _read_menu('input.json')
 
     actual = feed.render_menu(menu)
 
-    expected = _expected_menu_feed()
+    expected = _read_feed('menu_output.xml')
+    assert expected == actual
+
+
+def test_empty_menu():
+    menu = _read_menu('empty.json')
+
+    actual = feed.render_menu(menu)
+
+    expected = _read_feed('empty_menu_output.xml')
     assert expected == actual