feat(files): add a file factory to return factories

pkg/files/file_factory.go

@@ -0,0 +1,23 @@
+package files
+
+import "fmt"
+
+type FileFactory interface {
+	NewFile(string) (File, error)
+}
+
+const (
+	Img = "image"
+	Doc = "document"
+)
+
+func BuildFactory(f string) (FileFactory, error) {
+	switch f {
+	case Img:
+		return new(ImageFactory), nil
+	case Doc:
+		return new(DocumentFactory), nil
+	default:
+		return nil, fmt.Errorf("factory with id %s not recognized", f)
+	}
+}

pkg/files/file_factory_test.go

@@ -0,0 +1,39 @@
+package files
+
+import (
+	"testing"
+
+	"github.com/danvergara/morphos/pkg/files/documents"
+	"github.com/danvergara/morphos/pkg/files/images"
+	"github.com/stretchr/testify/require"
+)
+
+func TestImageFactory(t *testing.T) {
+	imgF, err := BuildFactory(Img)
+	require.NoError(t, err)
+
+	imageFile, err := imgF.NewFile(images.PNG)
+	require.NoError(t, err)
+
+	png, ok := imageFile.(Image)
+	if !ok {
+		t.Fatal("struct assertion has failed")
+	}
+
+	t.Logf("Png image has type %s", png.ImageType())
+}
+
+func TestDocumentFactory(t *testing.T) {
+	docF, err := BuildFactory(Doc)
+	require.NoError(t, err)
+
+	docFile, err := docF.NewFile(documents.PDF)
+	require.NoError(t, err)
+
+	pdf, ok := docFile.(Document)
+	if !ok {
+		t.Fatal("struct assertion has failed")
+	}
+
+	t.Logf("PDF document has type %s", pdf.DocumentType())
+}