add triple xor test

tests/nodes/exec_xor.rb

@@ -27,7 +27,7 @@ class TestExecXorNode < Minitest::Unit::TestCase
         assert_equal(computed_outputs, [1,3,0,0])
     end
 
-    def test_simple22xor()
+    def test_double22xor()
         a_node = InputNode.new(name:"input_a",dimensions:[2,2])
         b_node = InputNode.new(name:"input_b",dimensions:[2,2])
         c_node = XorNode.new(name:"xor_c", inputs:[a_node.outputs[0], b_node.outputs[0]])
@@ -42,4 +42,21 @@ class TestExecXorNode < Minitest::Unit::TestCase
         assert_equal(computed_outputs, [1,1,1,1])
     end
 
+    def test_triple22xor()
+        a_node = InputNode.new(name:"input_a",dimensions:[2,2])
+        b_node = InputNode.new(name:"input_b",dimensions:[2,2])
+        c_node = XorNode.new(name:"xor_c", inputs:[a_node.outputs[0], b_node.outputs[0]])
+        d_node = InputNode.new(name:"input_d", dimensions:[2,2])
+        e_node = XorNode.new(name:"xor_e", inputs:[c_node.outputs[0], d_node.outputs[0]])
+        f_node = InputNode.new(name:"input_f", dimensions:[2,2])
+        g_node = XorNode.new(name:"xor_g", inputs:[e_node.outputs[0], f_node.outputs[0]])
+        computed_outputs = compute_set_of_operators(
+            [1,2,3,4]+[0,1,3,4]+[0,2,1,1]+[1,1,1,1], # input values
+            a_node.flatten_output(0)+b_node.flatten_output(0)+d_node.flatten_output(0)+f_node.flatten_output(0), # input variables
+            g_node.flatten_output(0), # output variables
+            e_node.operators+c_node.operators+g_node.operators
+        )
+        assert_equal(computed_outputs, [0,0,0,0])
+    end
+
 end
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