Fix and test idempotent updates

uwescience · Mar 21, 2014 · fc93888 · fc93888
1 parent 97d63c9
commit fc93888
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diff --git a/raco/cev_test.py b/raco/cev_test.py
@@ -19,3 +19,19 @@ def test_cev(self):
 
         for i in range(5, 12):
             self.assertEquals(cev.get_equivalent_columns(i), {i})
+
+    def test_cev_idempotent(self):
+        cev = physprop.ColumnEquivalenceClassSet(12)
+
+        cev.merge(2, 1)
+        cev.merge(4, 3)
+        cev.merge(3, 2)
+        cev.merge(2, 1)
+        cev.merge(4, 3)
+        cev.merge(3, 2)
+
+        for i in range(1, 5):
+            self.assertEquals(cev.get_equivalent_columns(i), {1, 2, 3, 4})
+
+        for i in range(5, 12):
+            self.assertEquals(cev.get_equivalent_columns(i), {i})
diff --git a/raco/physprop.py b/raco/physprop.py
@@ -39,6 +39,10 @@ def merge(self, col1, col2):
 
         min_rep = self.member_dict[_min]
         max_rep = self.member_dict[_max]
+
+        if min_rep == max_rep:
+            return
+
         min_members = self.rep_dict[min_rep]
         max_members = self.rep_dict[max_rep]