Add checking file permissions

Author: wcampbell0x2a

Diff for: src/lib.rs

@@ -48,6 +48,7 @@ pub fn is_different<A: AsRef<Path>, B: AsRef<Path>>(a_base: A, b_base: B) -> Res
         if a.depth() != b.depth()
             || a.file_type() != b.file_type()
             || a.file_name() != b.file_name()
+            || a.metadata()?.permissions() != b.metadata()?.permissions()
             || (a.file_type().is_file() && read_to_vec(a.path())? != read_to_vec(b.path())?)
         {
             return Ok(true);

Diff for: tests/permissions/bad/dir1/file

@@ -57,6 +57,12 @@ fn reflexive() {
     assert!(dir_diff::is_different("tests/reflexive/dir1", "tests/reflexive/dir2").unwrap());
 }
 
+#[test]
+fn binary_permissions() {
+    assert!(!dir_diff::is_different("tests/permissions/good/dir1", "tests/permissions/good/dir2").unwrap());
+    assert!(dir_diff::is_different("tests/permissions/bad/dir1", "tests/permissions/bad/dir2").unwrap());
+}
+
 #[test]
 fn dirs_differ() {
     assert!(dir_diff::is_different("tests/dirs_differ/dir1", "tests/dirs_differ/dir2").unwrap());