rustdoc: Add parse::from_str for testing purposes

src/rustdoc/rustdoc.rs

@@ -178,14 +178,26 @@ fn doc_header(rd: rustdoc, name: str) {
 }
 
 mod parse {
-    fn from_file(file: str) -> @ast::crate {
+    export from_file, from_str;
+
+    fn new_parse_sess() -> parser::parse_sess {
         let cm = codemap::new_codemap();
         let sess = @{
             cm: cm,
             mutable next_id: 0,
             diagnostic: diagnostic::mk_handler(cm, none)
         };
-        parser::parse_crate_from_source_file(file, [], sess)
+        ret sess;
+    }
+
+    fn from_file(file: str) -> @ast::crate {
+        parser::parse_crate_from_source_file(
+            file, [], new_parse_sess())
+    }
+
+    fn from_str(source: str) -> @ast::crate {
+        parser::parse_crate_from_source_str(
+            "-", source, [], new_parse_sess())
     }
 }