budget.addExpenditure(exp1);
budget.addExpenditure(exp2);
budget.addExpenditure(exp3);
budget.addExpenditure(exp4);
budget.addExpenditure(exp5);
budget.addExpenditure(exp6);
BudgetService bs = new BudgetService(new AdjacencyMatrixGraphFactory());
Graph graph = bs.resolveBudget(budget);
assertEquals(graph.getVertexSet().size(), 4);