Added test

pkg/credentials/github_test.go

@@ -0,0 +1,28 @@
+package credentials_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	"github.com/OctopusDeploy/go-octopusdeploy/v2/internal"
+	"github.com/OctopusDeploy/go-octopusdeploy/v2/pkg/credentials"
+	"github.com/kinbiko/jsonassert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGitHubMarshalJSON(t *testing.T) {
+	id := internal.GetRandomName()
+	reference := credentials.NewGitHub(id)
+
+	referenceAsJSON, err := json.Marshal(reference)
+	require.NoError(t, err)
+	require.NotNil(t, referenceAsJSON)
+
+	expectedJSON := fmt.Sprintf(`{
+		"Id": "%s",
+		"Type": "%s"
+	}`, id, credentials.GitCredentialTypeGitHub)
+
+	jsonassert.New(t).Assertf(expectedJSON, string(referenceAsJSON))
+}