Added unit test for graph update rules.

quad/computation_graph/test/test_computation_graph.c

@@ -145,6 +145,21 @@ int graph_test_self_loop() {
     return 0;
 }
 
+int graph_test_update_rules() {
+    struct computation_graph *graph = create_graph();
+    int cblock = graph_add_node_const(graph, "const");
+    int acum_b = graph_add_node_accum(graph, "accumulator");
+    graph_set_source(graph, acum_b, ACCUM_IN, cblock, CONST_VAL);
+
+    graph_set_param_val(graph, cblock, CONST_SET, 3);
+    int to_compute_for[1] = {acum_b};
+    graph_compute_nodes(graph, to_compute_for, 1);
+    graph_compute_nodes(graph, to_compute_for, 1);
+
+    double result = graph_get_output(graph, acum_b, ACCUMULATED);
+    return nequal(result, 3);
+}
+
 
 int main() {
     int success = 0;
@@ -155,5 +170,6 @@ int main() {
     test(graph_test_single_run, "Test that blocks only get executed once");
     test(graph_test_reset_rules, "Tests that already connected blocks don't get reset");
     test(graph_test_self_loop, "Tests that a self-loop computation terminates");
+    test(graph_test_update_rules, "Tests that nodes only update when their inputs change");
     test_summary();
 }