@Test
    public void insertKeepsMinimumValueAtTop() {
        int minimumValue = Integer.MAX_VALUE;
        Random r = new Random();
        for (int i = 0; i < 100; i++) {
            int thisValue = r.nextInt(5000);
            h.insert(new Vertex(0, thisValue));
            if(thisValue < minimumValue) {
                minimumValue = thisValue;
            }
            assertEquals(minimumValue, h.min().getDistance());
        }
    }