simplify format.Unmarshal; improve tests (#631)

pkg/format/vp9_test.go

@@ -33,35 +33,3 @@ func TestVP9DecEncoder(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, []byte{0x82, 0x49, 0x83, 0x42, 0x0, 0x77, 0xf0, 0x32, 0x34}, byts)
 }
-
-func FuzzUnmarshalVP9(f *testing.F) {
-	f.Fuzz(func(
-		_ *testing.T,
-		a bool,
-		b string,
-		c bool,
-		d string,
-		e bool,
-		f string,
-	) {
-		ma := map[string]string{}
-
-		if a {
-			ma["max-fr"] = b
-		}
-
-		if c {
-			ma["max-fs"] = d
-		}
-
-		if e {
-			ma["profile-id"] = f
-		}
-
-		fo, err := Unmarshal("audio", 96, "VP9/90000", ma)
-		if err == nil {
-			fo.RTPMap()
-			fo.FMTP()
-		}
-	})
-}