Added e2e test case for buildResponse function

Signed-off-by: viveksahu26 <vivekkumarsahu650@gmail.com>

src/buildURLresponse_test.go

@@ -0,0 +1,16 @@
+package src
+
+import (
+	"testing"
+
+	"gotest.tools/assert"
+)
+
+func TestBuildResonse(t *testing.T) {
+	expected := BuildURLWithResponse("localhost:8080", "duj3P^+d*C", "http://viveksahu.com")
+	actual := &URLResponse{
+		OriginalURL: "http://viveksahu.com",
+		ShortURL:    "http://localhost:8080/duj3P^+d*C",
+	}
+	assert.Equal(t, expected.ShortURL, actual.ShortURL)
+}