tests: improve metadata test
tests: improve metadata test

ensonic/gstreamer,lubosz/gstreamer,ensonic/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,surround-io/gstreamer,collects/gstreamer,surround-io/gstreamer,StreamUtils/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,collects/gstreamer,mparis/gstreamer,jpakkane/gstreamer,StreamUtils/gstreamer,cfoch/gstreamer,cablelabs/gstreamer,cablelabs/gstreamer,Lachann/gstreamer,justinjoy/gstreamer,krichter722/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,lovebug356/gstreamer,ensonic/gstreamer,cfoch/gstreamer,mparis/gstreamer,lovebug356/gstreamer,jpakkane/gstreamer,centricular/gstreamer,mparis/gstreamer,cfoch/gstreamer,lubosz/gstreamer,krieger-od/gstreamer,jpxiong/gstreamer,centricular/gstreamer,krichter722/gstreamer,centricular/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,surround-io/gstreamer,centricular/gstreamer,krichter722/gstreamer,mparis/gstreamer,mparis/gstreamer,lubosz/gstreamer,cfoch/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,cfoch/gstreamer,justinjoy/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,collects/gstreamer,StreamUtils/gstreamer,ensonic/gstreamer,krichter722/gstreamer,jpakkane/gstreamer,collects/gstreamer,surround-io/gstreamer,lovebug356/gstreamer,jpxiong/gstreamer,lubosz/gstreamer,krieger-od/gstreamer,justinjoy/gstreamer,jpxiong/gstreamer,lovebug356/gstreamer,Lachann/gstreamer,collects/gstreamer,lubosz/gstreamer,lovebug356/gstreamer,shelsonjava/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,krieger-od/gstreamer,cablelabs/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,Lachann/gstreamer