test: ☑️ add snapshot testing

.ignore

@@ -0,0 +1,3 @@
+# files listed here will be ignored by cargo watch, it also ignores .gitignore files.  Other tools migth use this file.  Add files to .gitignore instead, if cargo watch should ignore them and they don't need version control.
+**/*.snap
+**/*.snap.new

Cargo.toml

@@ -8,6 +8,14 @@ repository = "https://github.com/rodneylab/axum-graphql"
 rust-version = "1.70.0"
 description = "Rust GraphQL demo/test API written in Rust, using Axum for routing, async-graphql and SQLx."
 
+# Faster snapshot runs
+# See: https://docs.rs/insta/latest/insta/#optional-faster-runs
+[profile.dev.package.insta]
+opt-level = 3
+
+[profile.dev.package.similar]
+opt-level = 3
+
 # Faster cargo check and cargo build
 # See: https://github.com/launchbadge/sqlx#compile-time-verification
 [profile.dev.package.sqlx-macros]
@@ -42,6 +50,7 @@ tracing-subscriber = { version = "0.3.18", features = ["std", "env-filter"] }
 
 [dev-dependencies]
 http-body-util = "0.1.2"
+insta = { version = "1.41.1", features = ["json"] }
 mime = "0.3.17"
 serde_json = "1.0"
 tower = { version = "0.5.1", features = ['util'] }

src/model/snapshots/axum_graphql__model__tests__snapshot_hello_query.snap

@@ -0,0 +1,6 @@
+---
+source: src/model/tests.rs
+expression: body
+snapshot_kind: text
+---
+b"{\"data\":{\"hello\":\"Hello everybody!\"},\"extensions\":{\"traceId\":\"00000000000000000000000000000000\"}}"

src/model/tests.rs

@@ -102,6 +102,34 @@ mod helpers {
     }
 }
 
+#[tokio::test]
+async fn snapshot_hello_query() {
+    // arrange
+    let app = helpers::get_app().await;
+    let json_request_body: Value = json!({
+        "operationName":"HelloQuery",
+        "variables":{},
+        "query":"query HelloQuery { hello }"
+    });
+
+    // act
+    let response = app
+        .oneshot(
+            Request::builder()
+                .method(Method::POST)
+                .uri("/")
+                .header(header::CONTENT_TYPE, mime::APPLICATION_JSON.as_ref())
+                .body(Body::from(json_request_body.to_string()))
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+
+    // assert
+    let body = response.into_body().collect().await.unwrap().to_bytes();
+    insta::assert_debug_snapshot!(body);
+}
+
 #[tokio::test]
 async fn graphql_endpoint_responds_to_hello_query() {
     // arrange