assert-json-diff

This crate includes macros for comparing two serializable values by diffing their JSON representations. 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] and [serde_json] to perform the serialization.

Partial matching

If you want to assert that one JSON value is "included" in another use assert_json_include:

```rust use assertjsondiff::assertjsoninclude; use serde_json::json;

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" } } ] } });

assertjsoninclude!(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 ```

assert_json_include 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 use assertjsondiff::assertjsoninclude; use serde_json::json;

assertjsoninclude!( actual: json!({ "a": { "b": 1 }, }), expected: json!({ "a": {}, }) ) ```

However expected cannot contain additional data so this test fails:

```rust use assertjsondiff::assertjsoninclude; use serde_json::json;

assertjsoninclude!( actual: json!({ "a": {}, }), expected: json!({ "a": { "b": 1 }, }) ) ```

That will print

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

Exact matching

If you want to ensure two JSON values are exactly the same, use assert_json_eq.

```rust use assertjsondiff::assertjsoneq; use serde_json::json;

assertjsoneq!( json!({ "a": { "b": 1 } }), json!({ "a": {} }) ) ```

This will panic with the error message:

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

Further customization

You can use [assert_json_matches] to further customize the comparison.

License: MIT