rustdoc: Add a test that we can tolerate missing external crates

src/rustdoc/astsrv.rs

@@ -221,11 +221,17 @@ fn srv_should_resolve_non_existant_imports() {
 }
 
 #[test]
-fn srv_sholud_resolve_non_existant_uses() {
+fn srv_should_resolve_non_existant_uses() {
     let source = "use forble; fn a() { }";
     mk_srv_from_str(source);
 }
 
+#[test]
+fn should_ignore_external_import_paths_that_dont_exist() {
+    let source = "use forble; import forble::bippy;";
+    mk_srv_from_str(source);
+}
+
 fn exec<T>(
     srv: srv,
     f: fn~(ctxt: ctxt) -> T