refactor - tests

tests/rustfmt/main.rs

@@ -219,18 +219,16 @@ fn rustfmt_generates_no_error_if_failed_format_code_in_doc_comments() {
     assert!(stderr.is_empty());
     assert!(stdout.is_empty());
 }
+
 #[test]
 fn rustfmt_error_improvement_regarding_invalid_toml() {
     // See also https://github.com/rust-lang/rustfmt/issues/6302
-    let args = ["--config-path", "tests/config/issue-6302.toml"];
+    let invalid_toml_config = "tests/config/issue-6302.toml";
+    let args = ["--config-path", invalid_toml_config];
     let (_stdout, stderr) = rustfmt(&args);
 
-    let expected_error_message = "The file `rustfmt/tests/config/issue-6302.toml` failed to parse.\n                    Error details: invalid type: integer `2019`, expected string in `edition`";
+    let toml_path = Path::new(invalid_toml_config).canonicalize().unwrap();
+    let expected_error_message = format!("The file `{}` failed to parse", toml_path.display());
 
-    assert!(
-        stderr.contains(expected_error_message),
-        "Unexpected error message.\nExpected:\n{}\nGot:\n{}",
-        expected_error_message,
-        stderr
-    );
+    assert!(stderr.contains(&expected_error_message));
 }