Implement get_next_match

2 files changed, 18 insertions, 2 deletions

diff --git a/yarnhelper.py b/yarnhelper.py
index f313ab4..4501eab 100644
--- a/yarnhelper.py
+++ b/yarnhelper.py
@@ -16,13 +16,24 @@
 # =*= License: GPL-3+ =*=
 
 
+import os
+
+
 class YarnHelper(object):
 
+    def __init__(self):
+        self._env = dict(os.environ)
+        self._next_match = 1
+
     def set_environment(self, env):
-        pass
+        self._env = dict(env)
 
     def get_next_match(self):
-        raise Error('no next match')
+        name = 'MATCH_{}'.format(self._next_match)
+        if name not in self._env:
+            raise Error('no next match')
+        self._next_match += 1
+        return self._env[name]
 
 
 class Error(Exception):
diff --git a/yarnhelper_tests.py b/yarnhelper_tests.py
index 2e64f93..5c49901 100644
--- a/yarnhelper_tests.py
+++ b/yarnhelper_tests.py
@@ -28,3 +28,8 @@ class GetNextMatchTests(unittest.TestCase):
         h.set_environment({})
         with self.assertRaises(yarnhelper.Error):
             h.get_next_match()
+
+    def test_returns_match_if_there(self):
+        h = yarnhelper.YarnHelper()
+        h.set_environment({'MATCH_1': 'first'})
+        self.assertEqual(h.get_next_match(), 'first')