1 files changed, 87 insertions, 0 deletions
diff --git a/tests/run-make/unstable-feature-usage-metrics/rmake.rs b/tests/run-make/unstable-feature-usage-metrics/rmake.rs
new file mode 100644
index 00000000000..7e122def6b7
--- /dev/null
+++ b/tests/run-make/unstable-feature-usage-metrics/rmake.rs
@@ -0,0 +1,87 @@
+//! This test checks if unstable feature usage metric dump files `unstable-feature-usage*.json` work
+//! as expected.
+//!
+//! - Basic sanity checks on a default ICE dump.
+//!
+//! See <https://github.com/rust-lang/rust/issues/129485>.
+//!
+//! # Test history
+//!
+//! - forked from dump-ice-to-disk test, which has flakeyness issues on i686-mingw, I'm assuming
+//! those will be present in this test as well on the same platform
+
+//@ ignore-windows
+//FIXME(#128911): still flakey on i686-mingw.
+
+use std::path::{Path, PathBuf};
+
+use run_make_support::rfs::create_dir_all;
+use run_make_support::{
+    cwd, filename_contains, has_extension, rfs, run_in_tmpdir, rustc, serde_json,
+    shallow_find_files,
+};
+
+fn find_feature_usage_metrics<P: AsRef<Path>>(dir: P) -> Vec<PathBuf> {
+    shallow_find_files(dir, |path| {
+        if filename_contains(path, "unstable_feature_usage") && has_extension(path, "json") {
+            true
+        } else {
+            dbg!(path);
+            false
+        }
+    })
+}
+
+fn main() {
+    test_metrics_dump();
+    test_metrics_errors();
+}
+
+#[track_caller]
+fn test_metrics_dump() {
+    run_in_tmpdir(|| {
+        let metrics_dir = cwd().join("metrics");
+        create_dir_all(&metrics_dir);
+        rustc()
+            .input("lib.rs")
+            .env("RUST_BACKTRACE", "short")
+            .arg(format!("-Zmetrics-dir={}", metrics_dir.display()))
+            .run();
+        let mut metrics = find_feature_usage_metrics(&metrics_dir);
+        let json_path =
+            metrics.pop().expect("there should be one metrics file in the output directory");
+
+        assert_eq!(
+            0,
+            metrics.len(),
+            "there should be no more than one metrics file in the output directory"
+        );
+
+        let message = rfs::read_to_string(json_path);
+        let parsed: serde_json::Value =
+            serde_json::from_str(&message).expect("metrics should be dumped as json");
+        let expected = serde_json::json!(
+            {
+                "lib_features":[{"symbol":"ascii_char"}],
+                "lang_features":[{"symbol":"box_patterns","since":null}]
+            }
+        );
+
+        assert_eq!(expected, parsed);
+    });
+}
+
+#[track_caller]
+fn test_metrics_errors() {
+    run_in_tmpdir(|| {
+        rustc()
+            .input("lib.rs")
+            .env("RUST_BACKTRACE", "short")
+            .arg("-Zmetrics-dir=invaliddirectorythatdefinitelydoesntexist")
+            .run_fail()
+            .assert_stderr_contains(
+                "error: cannot dump feature usage metrics: No such file or directory",
+            )
+            .assert_stdout_not_contains("internal compiler error");
+    });
+}