Testing two JSON objects for equality ignoring child order in Java

Question

I'm looking for a JSON parsing library that supports comparing two JSON objects ignoring child order, specifically for unit testing JSON returning from a web service.

Do any of the major JSON libraries support this? The org.json library simply does a reference comparison.

Answer 1

Try Skyscreamer's JSONAssert.

Its non-strict mode has two major advantages that make it less brittle:

• Object extensibility (e.g. With an expected value of {id:1}, this would still pass: {id:1,moredata:'x'}.)
• Loose array ordering (e.g. ['dog','cat']==['cat','dog'])

In strict mode it behaves more like json-lib's test class.

A test looks something like this:

@Test
public void testGetFriends() {
    JSONObject data = getRESTData("/friends/367.json");
    String expected = "{friends:[{id:123,name:\"Corby Page\"}"
        + ",{id:456,name:\"Solomon Duskis\"}]}";
    JSONAssert.assertEquals(expected, data, false);
}

The parameters in the JSONAssert.assertEquals() call are expectedJSONString, actualDataString, and isStrict.

The result messages are pretty clear, which is important when comparing really big JSON objects.