Fixed sis file url prediction code

rpi_courses/web.py

@@ -29,23 +29,23 @@ def get(url, last_modified=None):
 def list_sis_files_for_date(date=None, url_base=SIS_URL):
     date = date or datetime.datetime.now()
     format = '%(base)s%(prefix)s%(year).4d%(month).2d.htm'
-    base = []
+    urls = []
     months = (1, 5, 9)
     prev_m = None
     prefixes = ['zs', 'zfs']
     def add_date(year, month):
         for prefix in prefixes:
-            base.append(format % dict(base=url_base, prefix=prefix, year=date.year, month=month))
-            base.append(format % dict(base=url_base, prefix=prefix, year=date.year, month=month))
+            urls.append(format % dict(base=url_base, prefix=prefix, year=year, month=month))
     for m in months:
         if m >= date.month:
-            add_date(date.year, m)
             if prev_m and prev_m < date.month:
                 add_date(date.year, prev_m)
+            add_date(date.year, m)
         prev_m = m
-    if not base:
-        add_date(date.year + 1, 1)
-    return base
+    if not urls:
+        add_date(date.year, months[-1])
+        add_date(date.year + 1, months[0])
+    return urls
 
 
 def list_sis_files(url_base=SIS_URL):

test/rpi_courses/test_web.py

@@ -1,10 +1,52 @@
+import datetime
 import unittest
 import urllib2
 from rpi_courses import web
 from mock import patch
 from constants import HTML
 
 
+class TestSisListUnits(unittest.TestCase):
+    def setUp(self):
+        self.url = "http://sis.rpi.edu/reg/"
+        self.maxDiff = None
+
+    def _urls(self, *urls):
+        return map(lambda x: self.url + x, urls)
+
+    def test_list_sis_files_for_date_for_the_year(self):
+        now = datetime.datetime(year=2013, month=1, day=1)
+        files = web.list_sis_files_for_date(now, url_base=self.url)
+        self.assertEqual(files, self._urls(
+            'zs201301.htm',
+            'zfs201301.htm',
+            'zs201305.htm',
+            'zfs201305.htm',
+            'zs201309.htm',
+            'zfs201309.htm'
+        ))
+
+    def test_list_sis_files_for_date_for_summer(self):
+        now = datetime.datetime(year=2013, month=6, day=1)
+        files = web.list_sis_files_for_date(now, url_base=self.url)
+        self.assertEqual(files, self._urls(
+            'zs201305.htm',
+            'zfs201305.htm',
+            'zs201309.htm',
+            'zfs201309.htm',
+        ))
+
+    def test_list_sis_files_for_date_for_fall(self):
+        now = datetime.datetime(year=2013, month=10, day=1)
+        files = web.list_sis_files_for_date(now, url_base=self.url)
+        self.assertEqual(files, self._urls(
+            'zs201309.htm',
+            'zfs201309.htm',
+            'zs201401.htm',
+            'zfs201401.htm'
+        ))
+
+
 class TestListUnits(unittest.TestCase):
     def setUp(self):
         self.url = "http://sis.rpi.edu/reg/rocs/"