refac: allowed image types and the size limit are a domain rule checked by the use case, not by the persistence layer

test/image_upload_rules_test.go

@@ -0,0 +1,110 @@
+package test
+
+import (
+	imageDomain "RenewCMS/internal/domain/image"
+	"RenewCMS/internal/infrastructure/useCases"
+	"errors"
+	"testing"
+)
+
+func TestImageUploadRules(t *testing.T) {
+	t.Run("CreateImage accepts every allowed content type within the size limit", func(t *testing.T) {
+		for _, contentType := range []string{"image/png", "image/jpeg", "image/webp", "image/svg+xml"} {
+			t.Run(contentType, func(t *testing.T) {
+				repo := newMockImageRepo()
+				createUc := useCases.NewCreateImageUseCase(repo)
+
+				result, err := createUc.CreateImage(imageDomain.ImageInput{
+					ContentType: contentType,
+					Size:        imageDomain.MaxImageSize,
+				})
+
+				if err != nil {
+					t.Fatalf("expected no error, got %v", err)
+				}
+				if result.ID == 0 {
+					t.Errorf("expected the created image, got zero value")
+				}
+				if len(repo.images) != 1 {
+					t.Errorf("expected Create to be called once, got %d calls", len(repo.images))
+				}
+			})
+		}
+	})
+
+	t.Run("CreateImage rejects a disallowed content type before reaching the repository", func(t *testing.T) {
+		repo := newMockImageRepo()
+		createUc := useCases.NewCreateImageUseCase(repo)
+
+		_, err := createUc.CreateImage(imageDomain.ImageInput{
+			ContentType: "application/pdf",
+			Size:        1024,
+		})
+
+		if !errors.Is(err, imageDomain.ErrImageTypeNotAllowed) {
+			t.Fatalf("expected ErrImageTypeNotAllowed, got %v", err)
+		}
+		if len(repo.images) != 0 {
+			t.Errorf("expected Create to never be called, got %d calls", len(repo.images))
+		}
+	})
+
+	t.Run("CreateImage rejects a file that exceeds the size limit", func(t *testing.T) {
+		repo := newMockImageRepo()
+		createUc := useCases.NewCreateImageUseCase(repo)
+
+		_, err := createUc.CreateImage(imageDomain.ImageInput{
+			ContentType: "image/png",
+			Size:        imageDomain.MaxImageSize + 1,
+		})
+
+		if !errors.Is(err, imageDomain.ErrImageTooLarge) {
+			t.Fatalf("expected ErrImageTooLarge, got %v", err)
+		}
+		if len(repo.images) != 0 {
+			t.Errorf("expected Create to never be called, got %d calls", len(repo.images))
+		}
+	})
+
+	t.Run("A file exactly at the size limit is accepted, one byte over is not", func(t *testing.T) {
+		repo := newMockImageRepo()
+		createUc := useCases.NewCreateImageUseCase(repo)
+
+		_, err := createUc.CreateImage(imageDomain.ImageInput{
+			ContentType: "image/png",
+			Size:        imageDomain.MaxImageSize,
+		})
+		if err != nil {
+			t.Fatalf("expected no error at the exact limit, got %v", err)
+		}
+		if len(repo.images) != 1 {
+			t.Fatalf("expected Create to be called once, got %d calls", len(repo.images))
+		}
+
+		_, err = createUc.CreateImage(imageDomain.ImageInput{
+			ContentType: "image/png",
+			Size:        imageDomain.MaxImageSize + 1,
+		})
+		if !errors.Is(err, imageDomain.ErrImageTooLarge) {
+			t.Fatalf("expected ErrImageTooLarge, got %v", err)
+		}
+		if len(repo.images) != 1 {
+			t.Errorf("expected Create to still be called exactly once in total, got %d calls", len(repo.images))
+		}
+	})
+
+	t.Run("A repository failure unrelated to type or size still propagates unchanged", func(t *testing.T) {
+		repo := newMockImageRepo()
+		repo.fail.failNextWith("Create", errRepositoryFailure)
+		createUc := useCases.NewCreateImageUseCase(repo)
+
+		_, err := createUc.CreateImage(imageDomain.ImageInput{
+			ContentType: "image/png",
+			Size:        1024,
+		})
+
+		if !errors.Is(err, errRepositoryFailure) {
+			t.Fatalf("expected the generic repository error, got %v", err)
+		}
+	})
+}