diff --git a/tests/system.rs b/tests/system.rs
index 1cdd43abbfa..d0769a855ac 100644
--- a/tests/system.rs
+++ b/tests/system.rs
@@ -26,8 +26,11 @@ fn get_path_string(dir_entry: io::Result<fs::DirEntry>) -> String {
     path.to_str().expect("Couldn't stringify path.").to_owned()
 }
 
-// For now, the only supported regression tests are idempotent tests - the input and
+// Integration tests and idempotence tests. The files in the tests/source are
+// formatted and compared to their equivalent in tests/target. The target file
+// and config can be overriden by annotations in the source file. The input and
 // output must match exactly.
+// Files in tests/target are checked to be unaltered by rustfmt.
 // FIXME(#28) would be good to check for error messages and fail on them, or at least report.
 #[test]
 fn system_tests() {
diff --git a/tests/idem/enum.rs b/tests/target/enum.rs
similarity index 100%
rename from tests/idem/enum.rs
rename to tests/target/enum.rs
diff --git a/tests/target/issue-64.rs b/tests/target/issue-64.rs
new file mode 100644
index 00000000000..c0660630203
--- /dev/null
+++ b/tests/target/issue-64.rs
@@ -0,0 +1,7 @@
+// Regression test for issue 64
+
+pub fn header_name<T: Header>() -> &'static str {
+    let name = <T as Header>::header_name();
+    let func = <T as Header>::header_name;
+    name
+}
diff --git a/tests/idem/tuple.rs b/tests/target/tuple.rs
similarity index 100%
rename from tests/idem/tuple.rs
rename to tests/target/tuple.rs