Add test coverage to core

core/user_test.go

@@ -0,0 +1,23 @@
+package core
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUserMention(t *testing.T) {
+	assert := assert.New(t)
+
+	// Create user object
+	user := &User{
+		ID: "sample_id",
+	}
+
+	assert.Equal("<@sample_id>", user.Mention())
+
+	// Test null user
+	var nullUser *User = nil
+	assert.NotEmpty(nullUser.Mention())
+
+}