Merge pull request #1 from matthew-brett/refactor-csa-test

MRG: A little refactoring

Author: kevlarkevin

nibabel/nicom/csareader.py

@@ -18,6 +18,8 @@
     'IS': int, # integer string
     }
 
+MAX_CSA_ITEMS = 199
+
 
 class CSAError(Exception):
     pass
@@ -116,7 +118,9 @@ def read(csa_str):
         # CSA1 specific length modifier
         if tag_no == 1:
             tag0_n_items = n_items
-        assert n_items < 200
+        if n_items > MAX_CSA_ITEMS:
+            raise CSAReadError('Expected <= {0} tags, got {1}'.format(
+                MAX_CSA_ITEMS, n_items))
         items = []
         for item_no in range(n_items):
             x0,x1,x2,x3 = up_str.unpack('4i')

nibabel/nicom/tests/test_csareader.py

@@ -68,9 +68,19 @@ def test_csa_len0():
 
 
 def test_csa_nitem():
-    # testing csa.read's ability to raise an error when n_items >200
-    assert_raises(AssertionError, csa.read, CSA_STR_200n_items)
-    assert csa.read(CSA_STR_valid)
+    # testing csa.read's ability to raise an error when n_items >= 200
+    assert_raises(csa.CSAReadError, csa.read, CSA_STR_200n_items)
+    # OK when < 200
+    csa_info = csa.read(CSA_STR_valid)
+    assert_equal(len(csa_info['tags']), 1)
+    # OK after changing module global
+    n_items_thresh = csa.MAX_CSA_ITEMS
+    try:
+        csa.MAX_CSA_ITEMS = 1000
+        csa_info = csa.read(CSA_STR_200n_items)
+        assert_equal(len(csa_info['tags']), 1)
+    finally:
+        csa.MAX_CSA_ITEMS = n_items_thresh
 
 
 def test_csa_params():