assert-json-diff

This crate includes an assert macro for comparing two JSON values. It is designed to give much more helpful error messages than the standard [assert_eq!]. It basically does a diff of the two objects and tells you the exact differences. This is useful when asserting that two large JSON objects are the same.

It uses the [serde_json::Value] type to represent JSON.

Example

```rust

[macro_use]

extern crate assertjsondiff;

[macro_use]

extern crate serde_json;

// probably with #[test] attribute fn some_test() { let a = json!({ "data": { "users": [ { "id": 1, "country": { "name": "Denmark" } }, { "id": 24, "country": { "name": "Denmark" } } ] } });

let b = json!({
    "data": {
        "users": [
            {
                "id": 1,
                "country": {
                    "name": "Sweden"
                }
            },
            {
                "id": 2,
                "country": {
                    "name": "Denmark"
                }
            }
        ]
    }
});

assert_json_eq!(actual: a, expected: b)

} ```

This will panic with the error message:

``` json atoms at path ".data.users[0].country.name" are not equal: expected: "Sweden" actual: "Denmark"

json atoms at path ".data.users[1].id" are not equal: expected: 2 actual: 24 ```

Additional data

It allows extra data in actual but not in expected. That is so you can verify just a part of the JSON without having to specify the whole thing. For example this test passes:

```rust

[macro_use]

extern crate assertjsondiff;

[macro_use]

extern crate serde_json;

// probably with #[test] attribute fn sometest() { assertjson_eq!( actual: json!({ "a": { "b": 1 }, }), expected: json!({ "a": {}, }) ) } ```

However expected cannot contain additional data so this test fails:

```rust

[macro_use]

extern crate assertjsondiff;

[macro_use]

extern crate serde_json;

// probably with #[test] attribute fn sometest() { assertjson_eq!( actual: json!({ "a": {}, }), expected: json!({ "a": { "b": 1 }, }) ) } ```

That will print

json atom at path ".a.b" is missing from expected

The macro

The assert_json_eq! macro can be called with or without typing actual: and expected:

```rust

[macro_use]

extern crate assertjsondiff;

[macro_use]

extern crate serde_json;

// probably with #[test] attribute fn sometest() { assertjson_eq!( actual: json!(true), expected: json!(true) ) }

// probably with #[test] attribute fn someothertest() { assertjsoneq!( json!(true), json!(true) ) } ```

The version that includes actual: and expected: is preferred because it makes it very clear which is which and there which can contain additional data

License: MIT