improve test coverage and display output

packages/check/Cargo.toml

@@ -19,7 +19,8 @@ serde = { version = "1.0.136", features = ["derive"] }
 prettyplease = { package = "prettier-please", version = "0.1.16", features = [
     "verbatim",
 ] }
-owo-colors = "3.5.0"
+owo-colors = { version = "3.5.0", features = ["supports-colors"] }
 
 [dev-dependencies]
+indoc = "2.0.3"
 pretty_assertions = "1.2.1"