tests: use the cached json errors instead of calling rustc

Author: pietroalbini

tests/parse_and_replace.rs

@@ -29,8 +29,6 @@ mod fixmode {
 
 mod settings {
     // can be set as env var to debug
-    pub const CHECK_JSON: &str = "RUSTFIX_TEST_CHECK_JSON";
-    pub const RECORD_JSON: &str = "RUSTFIX_TEST_RECORD_JSON";
     pub const RECORD_FIXED_RUST: &str = "RUSTFIX_TEST_RECORD_FIXED_RUST";
 }
 
@@ -62,20 +60,6 @@ fn compile(file: &Path, mode: &str) -> Result<Output, Error> {
     Ok(res)
 }
 
-fn compile_and_get_json_errors(file: &Path, mode: &str) -> Result<String, Error> {
-    let res = compile(file, mode)?;
-    let stderr = String::from_utf8(res.stderr)?;
-
-    match res.status.code() {
-        Some(0) | Some(1) | Some(101) => Ok(stderr),
-        _ => Err(format_err!(
-            "failed with status {:?}: {}",
-            res.status.code(),
-            stderr
-        )),
-    }
-}
-
 fn compiles_without_errors(file: &Path, mode: &str) -> Result<(), Error> {
     let res = compile(file, mode)?;
 
@@ -122,7 +106,8 @@ fn diff(expected: &str, actual: &str) -> String {
             write!(
                 &mut res,
                 "differences found (+ == actual, - == expected):\n"
-            ).unwrap();
+            )
+            .unwrap();
             different = true;
         }
         for diff in diff.lines() {
@@ -149,39 +134,12 @@ fn test_rustfix_with_file<P: AsRef<Path>>(file: P, mode: &str) -> Result<(), Err
 
     debug!("next up: {:?}", file);
     let code = read_file(file).context(format!("could not read {}", file.display()))?;
-    let errors = compile_and_get_json_errors(file, mode)
-        .context(format!("could compile {}", file.display()))?;
+    let errors = read_file(&json_file)
+        .with_context(|_| format!("could not load json suggestions for {}", file.display()))?;
     let suggestions =
         rustfix::get_suggestions_from_json(&errors, &HashSet::new(), filter_suggestions)
             .context("could not load suggestions")?;
 
-    if std::env::var(settings::RECORD_JSON).is_ok() {
-        use std::io::Write;
-        let mut recorded_json = fs::File::create(&file.with_extension("recorded.json")).context(
-            format!("could not create recorded.json for {}", file.display()),
-        )?;
-        recorded_json.write_all(errors.as_bytes())?;
-    }
-
-    if std::env::var(settings::CHECK_JSON).is_ok() {
-        let expected_json = read_file(&json_file).context(format!(
-            "could not load json fixtures for {}",
-            file.display()
-        ))?;
-        let expected_suggestions =
-            rustfix::get_suggestions_from_json(&expected_json, &HashSet::new(), filter_suggestions)
-                .context("could not load expected suggesitons")?;
-
-        ensure!(
-            expected_suggestions == suggestions,
-            "got unexpected suggestions from clippy:\n{}",
-            diff(
-                &format!("{:?}", expected_suggestions),
-                &format!("{:?}", suggestions)
-            )
-        );
-    }
-
     let fixed = apply_suggestions(&code, &suggestions)
         .context(format!("could not apply suggestions to {}", file.display()))?;