Solution: Test Calculator

---

examples/test-calc/calc_test.go

package main

import "testing"

func TestCalc(t *testing.T) {
    result, err := calc(2, "+", 3)

    if err != nil {
        t.Errorf("Error found where not expected %v", err)
    }
    if result != 5 {
        t.Errorf("Expected 5 received %v", result)
    }
}