Adds pass command to clif-util. (#487)

* Adds pass command to clif-util.

lib/filetests/src/lib.rs

@@ -79,6 +79,24 @@ pub fn run(verbose: bool, files: &[String]) -> TestResult {
     runner.run()
 }
 
+/// Used for 'pass' subcommand.
+/// Commands are interpreted as test and executed.
+///
+/// Directories are scanned recursively for test cases ending in `.clif`.
+///
+pub fn run_passes(verbose: bool, passes: &[String], target: &str, file: &String) -> TestResult {
+    let mut runner = TestRunner::new(verbose);
+
+    let path = Path::new(file);
+    if path.is_file() {
+        runner.push_test(path);
+    } else {
+        runner.push_dir(path);
+    }
+
+    runner.run_passes(passes, target)
+}
+
 /// Create a new subcommand trait object to match `parsed.command`.
 ///
 /// This function knows how to create all of the possible `test <foo>` commands that can appear in