Rewrite rustdoc-determinism test in Rust

Author: JoverZhang

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -246,7 +246,6 @@ run-make/rlib-format-packed-bundled-libs-3/Makefile
 run-make/rlib-format-packed-bundled-libs/Makefile
 run-make/rmeta-preferred/Makefile
 run-make/rustc-macro-dep-files/Makefile
-run-make/rustdoc-determinism/Makefile
 run-make/rustdoc-error-lines/Makefile
 run-make/rustdoc-io-error/Makefile
 run-make/rustdoc-map-file/Makefile

tests/run-make/rustdoc-determinism/Makefile

@@ -0,0 +1,18 @@
+use run_make_support::{diff, rustc, rustdoc, tmp_dir};
+
+/// Assert that the search index is generated deterministically, regardless of the
+/// order that crates are documented in.
+fn main() {
+    let dir_first = tmp_dir().join("first");
+    rustdoc().out_dir(&dir_first).input("foo.rs").run();
+    rustdoc().out_dir(&dir_first).input("bar.rs").run();
+
+    let dir_second = tmp_dir().join("second");
+    rustdoc().out_dir(&dir_second).input("bar.rs").run();
+    rustdoc().out_dir(&dir_second).input("foo.rs").run();
+
+    diff()
+        .expected_file(dir_first.join("search-index.js"))
+        .actual_file(dir_second.join("search-index.js"))
+        .run();
+}