fix: magic

- also swap assert description for stream download test

.travis.yml

@@ -5,5 +5,6 @@ addons:
       - qemu-utils
       - parted
       - jq
+      - libmagic-mgc
 script:
   - ./test.sh

tests/maas.sh

@@ -5,7 +5,7 @@ function test_stream()
     local mimetype
     get_streams
     mimetype="$(file -b --mime-type "$streams")"
-    assertEquals "$mimetype" "application/json"
+    assertEquals "application/json" "$mimetype"
     cleanup_temp
 }