Address review comments, add tests

src/librustc/front/test.rs

@@ -545,8 +545,7 @@ fn mk_test_desc_and_fn_rec(cx: &TestCtxt, test: &Test) -> Gc<ast::Expr> {
     let mut visible_path = match cx.toplevel_reexport {
         Some(id) => vec![id],
         None => {
-            cx.sess.span_bug(
-                DUMMY_SP,
+            cx.sess.bug(
                 "expected to find top-level re-export name, but found None"
             );
         }

src/test/run-pass/issue-16597-empty.rs

@@ -0,0 +1,14 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags:--test
+
+// This verifies that the test generation doesn't crash when we have
+// no tests - for more information, see PR #16892.

src/test/run-pass/issue-16597.rs

@@ -0,0 +1,20 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags:--test
+
+#![feature(globs)]
+
+mod test {
+    use super::*;
+
+    #[test]
+    fn test(){}
+}