Test for MediaDescription.WithFingerprint

This tests that an attribute is added, and the key
and value of that attribute are as expected.

media_description_test.go

@@ -0,0 +1,20 @@
+package sdp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWithFingerprint(t *testing.T) {
+	m := new(MediaDescription)
+
+	assert.Equal(t, []Attribute(nil), m.Attributes)
+
+	m = m.WithFingerprint("testalgorithm", "testfingerprint")
+
+	assert.Equal(t, []Attribute{
+		{"fingerprint", "testalgorithm testfingerprint"},
+	},
+		m.Attributes)
+}