Index: mime-guess/src/lib.rs
===================================================================
--- mime-guess.orig/src/lib.rs
+++ mime-guess/src/lib.rs
@@ -432,7 +432,9 @@ pub fn octet_stream() -> Mime {
 mod tests {
     include!("mime_types.rs");
 
-    use super::{expect_mime, from_ext, from_path, get_mime_extensions_str};
+    use super::{expect_mime, from_ext, from_path};
+    #[cfg(feature="rev-mappings")]
+    use super::get_mime_extensions_str;
     #[allow(deprecated, unused_imports)]
     use std::ascii::AsciiExt;
 
@@ -527,6 +529,7 @@ mod tests {
         }
     }
 
+    #[cfg(feature="rev-mappings")]
     #[test]
     fn test_get_mime_extensions_str_no_panic_if_bad_mime() {
         assert_eq!(get_mime_extensions_str(""), None);