diff --git a/components/net/mime_classifier.rs b/components/net/mime_classifier.rs
index ab7a96867554..a9eac63c8cf0 100644
--- a/components/net/mime_classifier.rs
+++ b/components/net/mime_classifier.rs
@@ -39,7 +39,6 @@ impl MIMEClassifier {
                     apache_bug_flag: ApacheBugFlag,
                     supplied_type: &Option<(String, String)>,
                     data: &[u8]) -> Option<(String, String)> {
-
         match *supplied_type {
             None => self.sniff_unknown_type(no_sniff_flag, data),
             Some((ref media_type, ref media_subtype)) => {
@@ -279,8 +278,8 @@ struct BinaryOrPlaintextClassifier;
 
 impl BinaryOrPlaintextClassifier {
     fn classify_impl(&self, data: &[u8]) -> (&'static str, &'static str) {
-        if data == &[0xFFu8, 0xFEu8] ||
-           data == &[0xFEu8, 0xFFu8] ||
+        if data.starts_with(&[0xFFu8, 0xFEu8]) ||
+           data.starts_with(&[0xFEu8, 0xFFu8]) ||
            data.starts_with(&[0xEFu8, 0xBBu8, 0xBFu8])
         {
             ("text", "plain")
diff --git a/tests/unit/net/mime_classifier.rs b/tests/unit/net/mime_classifier.rs
index 02561ae5ab29..b8538dc9ab81 100644
--- a/tests/unit/net/mime_classifier.rs
+++ b/tests/unit/net/mime_classifier.rs
@@ -494,7 +494,7 @@ fn test_sniff_utf_8_bom_with_apache_flag_on() {
     test_sniff_with_flags(&PathBuf::from("text/plain/utf8bom.txt"),
                                   "text",
                                   "plain",
-                                  None,
+                                  Some(("dummy", "text")),
                                   NoSniffFlag::OFF,
                                   ApacheBugFlag::ON);
 }
@@ -504,7 +504,7 @@ fn test_sniff_utf_16be_bom_with_apache_flag_on() {
     test_sniff_with_flags(&PathBuf::from("text/plain/utf16bebom.txt"),
                                   "text",
                                   "plain",
-                                  None,
+                                  Some(("dummy", "text")),
                                   NoSniffFlag::OFF,
                                   ApacheBugFlag::ON);
 }
@@ -514,7 +514,7 @@ fn test_sniff_utf_16le_bom_with_apache_flag_on() {
     test_sniff_with_flags(&PathBuf::from("text/plain/utf16lebom.txt"),
                                   "text",
                                   "plain",
-                                  None,
+                                  Some(("dummy", "text")),
                                   NoSniffFlag::OFF,
                                   ApacheBugFlag::ON);
 }
@@ -524,7 +524,7 @@ fn test_sniff_octet_stream_apache_flag_on() {
     test_sniff_with_flags(&PathBuf::from("unknown/binary_file"),
                                   "application",
                                   "octet-stream",
-                                  None,
+                                  Some(("dummy", "binary")),
                                   NoSniffFlag::OFF,
                                   ApacheBugFlag::ON);
 }
@@ -532,9 +532,9 @@ fn test_sniff_octet_stream_apache_flag_on() {
 #[test]
 fn test_sniff_mp4_video_apache_flag_on() {
     test_sniff_with_flags(&PathBuf::from("video/mp4/test.mp4"),
-                          "video",
-                          "mp4",
-                          Some("video", "mp4"),
+                          "application",
+                          "octet-stream",
+                          Some(("video", "mp4")),
                           NoSniffFlag::OFF,
                           ApacheBugFlag::ON);
 }