test(transformer): add --debug option to transform conformance

tasks/transform_conformance/src/lib.rs

@@ -26,6 +26,7 @@ fn test() {
 pub struct TestRunnerOptions {
     pub filter: Option<String>,
     pub exec: bool,
+    pub debug: bool,
 }
 
 /// The test runner which walks the babel repository and searches for transformation tests.

tasks/transform_conformance/src/main.rs

@@ -7,6 +7,7 @@ fn main() {
     let options = TestRunnerOptions {
         filter: args.opt_value_from_str("--filter").unwrap(),
         exec: args.contains("--exec"),
+        debug: args.contains("--debug"),
     };
 
     TestRunner::new(options.clone()).run();

tasks/transform_conformance/src/test_case.rs

@@ -191,6 +191,10 @@ impl TestCase {
     }
 
     pub fn test(&mut self, options: &TestRunnerOptions) {
+        if options.debug {
+            println!("{:?}", &self.path);
+        }
+
         let filtered = options.filter.is_some();
         match self.kind {
             TestCaseKind::Conformance => self.test_conformance(filtered),