test table constraint first argument. (#428)

* test table constraint first argument.

* add test

cpmpy/expressions/globalconstraints.py

@@ -296,6 +296,9 @@ class Table(GlobalConstraint):
     """The values of the variables in 'array' correspond to a row in 'table'
     """
     def __init__(self, array, table):
+        array = flatlist(array)
+        if not all(isinstance(x, Expression) for x in array):
+            raise TypeError("the first argument of a Table constraint should only contain variables/expressions")
         super().__init__("table", [array, table])
 
     def decompose(self):

tests/test_globalconstraints.py

@@ -815,4 +815,15 @@ def test_count(self):
         a = cp.boolvar()
 
         self.assertTrue(cp.Model([cp.Count([x,y],z) == 1]).solve())
-        self.assertRaises(TypeError, cp.Count, [x,y],[x,False])
+        self.assertRaises(TypeError, cp.Count, [x,y],[x,False])
+
+    def test_table(self):
+        iv = cp.intvar(-8,8,3)
+
+        constraints = [cp.Table([iv[0], [iv[1], iv[2]]], [ (5, 2, 2)])] # not flatlist, should work
+        model = cp.Model(constraints)
+        self.assertTrue(model.solve())
+
+        self.assertRaises(TypeError, cp.Table, [iv[0], iv[1], iv[2], 5], [(5, 2, 2)])
+        self.assertRaises(TypeError, cp.Table, [iv[0], iv[1], iv[2], [5]], [(5, 2, 2)])
+        self.assertRaises(TypeError, cp.Table, [iv[0], iv[1], iv[2], ['a']], [(5, 2, 2)])