Added yield_fixedblock
diff --git a/tests/test_blocks.py b/tests/test_blocks.py
index 8481c3c..ce5f03a 100644
--- a/tests/test_blocks.py
+++ b/tests/test_blocks.py
@@ -65,4 +65,11 @@
         varblocks = list(blocks.yield_varblocks(infile))
         self.assertEqual(['12345', 'Sybren'], varblocks)
 
+class FixedblockTest(unittest.TestCase):
 
+    def test_yield_fixedblock(self):
+
+        infile = StringIO('123456Sybren')
+
+        fixedblocks = list(blocks.yield_fixedblocks(infile, 6))
+        self.assertEqual(['123456', 'Sybren'], fixedblocks)