Add RFC for providing ignore test message

text/0000-ignore-test-message.md

@@ -0,0 +1,162 @@
+- Feature Name: `ignore_test_message`
+- Start Date: 2022-01-07
+- RFC PR: [rust-lang/rfcs#0000](https://github.com/rust-lang/rfcs/pull/0000)
+- Rust Issue: [rust-lang/rust#0000](https://github.com/rust-lang/rust/issues/0000)
+
+# Summary
+[summary]: #summary
+
+Providing ignore message if the message is provided.
+
+# Motivation
+[motivation]: #motivation
+
+There may be meta value as a message for ignoring attributes on a test case.
+[the-ignore-attribute](https://github.com/rust-lang/reference/blob/master/src/attributes/testing.md#the-ignore-attribute)
+
+
+Consider following test
+```rust
+#[test]
+#[ignore = "not yet implemented"]
+fn test_ignored() {
+    // …
+}
+#[test]
+fn test_works() {
+    // …
+}
+```
+
+Currently, only ignored flag will print in the summary of `cargo test`.
+
+```
+running 2 tests
+test tests::test_ignored ... ignored
+test tests::test_works ... ok
+
+test result: ok. 1 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.00s
+```
+
+It is good to show the message if exist as following.
+
+```
+running 2 tests
+test tests::test_ignored ... ignored, not yet implemented
+test tests::test_works ... ok
+
+test result: ok. 1 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.00s
+```
+
+This RFC aims to easier use for large system.
+
+# Guide-level explanation
+[guide-level-explanation]: #guide-level-explanation
+
+
+Currently the `TestDesc` only store ignore flag, when the test case built, we can only know the case is ignore or not.
+
+[https://github.com/rust-lang/rust/blob/master/library/test/src/types.rs#L121-L130](https://github.com/rust-lang/rust/blob/master/library/test/src/types.rs#L121-L130)
+
+
+```rust
+#[derive(Clone, Debug)]
+pub struct TestDesc {
+    pub name: TestName,
+    pub ignore: bool,
+    pub should_panic: options::ShouldPanic,
+    pub allow_fail: bool,
+    pub compile_fail: bool,
+    pub no_run: bool,
+    pub test_type: TestType,
+}
+
+```
+
+Actually, there are more than two case for ignore test, with message and without message.
+
+```rust
+enum Ignoring {
+  IgnoredWithMsg(String), // ignore with message
+  Ignored,
+  NotIgnored,
+  // ...
+}
+
+```
+
+The message meta value can be parsed here.
+
+[https://github.com/rust-lang/rust/blob/master/src/tools/compiletest/src/header.rs#L879-L882](https://github.com/rust-lang/rust/blob/master/src/tools/compiletest/src/header.rs#L879-L882)
+
+```rust
+    ignore = match config.parse_cfg_name_directive(ln, "ignore") {
+        ParsedNameDirective::Match => true,
+        ParsedNameDirective::NoMatch => ignore,
+    };
+```
+
+# Reference-level explanation
+[reference-level-explanation]: #reference-level-explanation
+
+None known.
+
+# Drawbacks
+[drawbacks]: #drawbacks
+
+None known.
+
+# Rationale and alternatives
+[rationale-and-alternatives]: #rationale-and-alternatives
+
+An alternative way is to show the message only user want, `cargo test --show-ignore-message`,
+and the default behavior still show `ignored` only.
+
+An alternative way to store the ignore message is to use additional field, for example `ignore_message`.
+
+```rust
+#[derive(Clone, Debug)]
+pub struct TestDesc {
+    pub name: TestName,
+    pub ignore: bool,
+    pub ignore_message: Option<String>,
+    pub should_panic: options::ShouldPanic,
+    pub allow_fail: bool,
+    pub compile_fail: bool,
+    pub no_run: bool,
+    pub test_type: TestType,
+}
+
+```
+
+If the ignore messages important for Rust user, and we want to print these out in summary,
+we need to store this some way.
+
+# Prior art
+[prior-art]: #prior-art
+
+Ignore test case with message in other language
+- [JUnit](http://junit.sourceforge.net/javadoc/org/junit/Ignore.html)
+
+# Unresolved questions
+[unresolved-questions]: #unresolved-questions
+
+None known.
+
+# Future possibilities
+[future-possibilities]: #future-possibilities
+
+Other test framework can utilize the feature, can provide more description on integration test case.
+
+Take [test-with](https://github.com/yanganto/test-with/) as example,
+
+```text
+running 2 tests
+test tests::test_backup_to_S3 ... ignored, because following variables not found: ACCESS_KEY, SECRET_KEY
+test tests::test_works ... ok
+
+test result: ok. 1 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.00s
+```
+
+People are requesting this kind of summary when running `cargo test`.
+[https://github.com/rust-lang/rust/issues/68007](https://github.com/rust-lang/rust/issues/68007)