added tests for messageTypes.go

channels/messageTypes_test.go

+package channels
+
+import "testing"
+
+func TestMessageType_String(t *testing.T) {
+	expected := []string{"Text", "AdminText", "Reaction", "Unknown messageType 4",
+		"Unknown messageType 5", "Unknown messageType 6", "Unknown messageType 7",
+		"Unknown messageType 8", "Unknown messageType 9",
+		"Unknown messageType 10"}
+
+	for i := 1; i <= 10; i++ {
+		mt := MessageType(i)
+		if mt.String() != expected[i-1] {
+			t.Errorf("Stringer failed on test %d, %s vs %s", i,
+				mt.String(), expected[i-1])
+		}
+	}
+}