(test) add test to reproduce #422

tests/escape.rs

@@ -3,7 +3,7 @@ extern crate handlebars;
 #[macro_use]
 extern crate serde_json;
 
-use handlebars::Handlebars;
+use handlebars::{handlebars_helper, Handlebars};
 
 #[test]
 fn test_escape_216() {
@@ -19,3 +19,25 @@ fn test_escape_216() {
         r"\\\\ foo bar foobar foo#bar foo//bar foo\foo foo\\\foo\\foo \\foo {{FOO}} {{FOO}}"
     );
 }
+
+#[test]
+fn test_string_no_escape_422() {
+    let mut hbs = Handlebars::new();
+
+    handlebars_helper!(replace: |input: str, from: str, to: str| {
+        input.replace(from, to)
+    });
+    hbs.register_helper("replace", Box::new(replace));
+
+    assert_eq!(
+        r#"some\ path"#,
+        hbs.render_template(r#"{{replace "some/path" "/" "\\ " }}"#, &())
+            .unwrap()
+    );
+
+    assert_eq!(
+        r#"some\path"#,
+        hbs.render_template(r#"{{replace "some/path" "/" "\\" }}"#, &())
+            .unwrap()
+    );
+}