UI test expectation path normalization not working on Windows in all cases?

[zackmdavis]

From discussion on PR #44942, a UI test exercising the JSON error format failed on the Appveyor Windows build (while the Unix-like tests passed) but it looks like the only part of the output that differs is the value of "file_name":

failures:
---- [ui] ui\lint\unused_parens_json_suggestion.rs stdout ----
	normalized stderr:
{"message":"unnecessary parentheses around assigned value","code":null,"level":"warning","spans":[{"file_name":"C://projects//rust//src/test//ui//lint//unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[{"message":"#[warn(unused_parens)] on by default","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"remove these parentheses","code":null,"level":"help","spans":[{"file_name":"C://projects//rust//src/test//ui//lint//unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":"1 / (2 + 3)","expansion":null}],"children":[],"rendered":"    let _a = 1 / (2 + 3);"}],"rendered":null}
expected stderr:
{"message":"unnecessary parentheses around assigned value","code":null,"level":"warning","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[{"message":"#[warn(unused_parens)] on by default","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"remove these parentheses","code":null,"level":"help","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":"1 / (2 + 3)","expansion":null}],"children":[],"rendered":"    let _a = 1 / (2 + 3);"}],"rendered":null}
diff of stderr:
-{"message":"unnecessary parentheses around assigned value","code":null,"level":"warning","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[{"message":"#[warn(unused_parens)] on by default","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"remove these parentheses","code":null,"level":"help","spans":[{"file_name":"$DIR/unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":"1 / (2 + 3)","expansion":null}],"children":[],"rendered":"    let _a = 1 / (2 + 3);"}],"rendered":null}
+{"message":"unnecessary parentheses around assigned value","code":null,"level":"warning","spans":[{"file_name":"C://projects//rust//src/test//ui//lint//unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[{"message":"#[warn(unused_parens)] on by default","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"remove these parentheses","code":null,"level":"help","spans":[{"file_name":"C://projects//rust//src/test//ui//lint//unused_parens_json_suggestion.rs","byte_start":976,"byte_end":989,"line_start":22,"line_end":22,"column_start":14,"column_end":27,"is_primary":true,"text":[{"text":"    let _a = (1 / (2 + 3));","highlight_start":14,"highlight_end":27}],"label":null,"suggested_replacement":"1 / (2 + 3)","expansion":null}],"children":[],"rendered":"    let _a = 1 / (2 + 3);"}],"rendered":null}

[estebank]

Mentoring instructions:

run_ui_tests has the code that runs the ui tests and calls normalize_output which does a simple replace from windows-isms to unix-isms. normalize_output accepts a list of extra replacements. normalize_output should check self.props.compile_flags for --error-format json being set and perform a replace before output.replace(&parent_dir_str, "$DIR").

When doing this change, make sure to update ui/lint/unused_parens_json_suggestion.rs removing ignore-windows too.

[clippered]

thanks for the tips. i would like to give this a go for my 1st PR, if you guys don't mind.