refactor(service): enrich conversion client result

backend/internal/service/card_service.go

@@ -7,8 +7,17 @@ import (
 	"card-to-iban/internal/card"
 )
 
+type ConversionResult struct {
+	IBAN               string
+	UpstreamHTTPStatus int
+	RawResponse        []byte
+}
+
 type CardToIBANClient interface {
-	Convert(ctx context.Context, cardNumber string) (string, error)
+	Convert(
+		ctx context.Context,
+		cardNumber string,
+	) (ConversionResult, error)
 }
 
 type CardService struct {
@@ -24,15 +33,15 @@ func NewCardService(client CardToIBANClient) *CardService {
 func (s *CardService) ConvertCardToIBAN(
 	ctx context.Context,
 	cardNumber string,
-) (string, error) {
+) (ConversionResult, error) {
 	if err := card.Validate(cardNumber); err != nil {
-		return "", err
+		return ConversionResult{}, err
 	}
 
-	iban, err := s.client.Convert(ctx, cardNumber)
+	result, err := s.client.Convert(ctx, cardNumber)
 	if err != nil {
-		return "", fmt.Errorf("convert card to iban: %w", err)
+		return result, fmt.Errorf("convert card to iban: %w", err)
 	}
 
-	return iban, nil
+	return result, nil
 }

backend/internal/service/card_service_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 type fakeCardToIBANClient struct {
-	iban            string
+	result          ConversionResult
 	err             error
 	called          bool
 	receivedCard    string
@@ -17,24 +17,28 @@ type fakeCardToIBANClient struct {
 func (f *fakeCardToIBANClient) Convert(
 	ctx context.Context,
 	cardNumber string,
-) (string, error) {
+) (ConversionResult, error) {
 	f.called = true
 	f.receivedCard = cardNumber
 	f.receivedContext = ctx
 
-	return f.iban, f.err
+	return f.result, f.err
 }
 
 func TestCardServiceConvertCardToIBANSuccess(t *testing.T) {
 	client := &fakeCardToIBANClient{
-		iban: "IR123456789012345678901234",
+		result: ConversionResult{
+			IBAN:               "IR123456789012345678901234",
+			UpstreamHTTPStatus: 200,
+			RawResponse:        []byte(`{"success":true}`),
+		},
 	}
 
 	service := NewCardService(client)
 
 	cardNumber := "6037991234567890"
 
-	iban, err := service.ConvertCardToIBAN(
+	result, err := service.ConvertCardToIBAN(
 		context.Background(),
 		cardNumber,
 	)
@@ -43,11 +47,19 @@ func TestCardServiceConvertCardToIBANSuccess(t *testing.T) {
 		t.Fatalf("ConvertCardToIBAN() unexpected error: %v", err)
 	}
 
-	if iban != client.iban {
+	if result.IBAN != client.result.IBAN {
 		t.Errorf(
 			"ConvertCardToIBAN() iban = %q, want %q",
-			iban,
-			client.iban,
+			result.IBAN,
+			client.result.IBAN,
+		)
+	}
+
+	if result.UpstreamHTTPStatus != client.result.UpstreamHTTPStatus {
+		t.Errorf(
+			"ConvertCardToIBAN() status = %d, want %d",
+			result.UpstreamHTTPStatus,
+			client.result.UpstreamHTTPStatus,
 		)
 	}
 
@@ -87,12 +99,16 @@ func TestCardServiceReturnsClientError(t *testing.T) {
 	clientErr := errors.New("upstream unavailable")
 
 	client := &fakeCardToIBANClient{
+		result: ConversionResult{
+			UpstreamHTTPStatus: 503,
+			RawResponse:        []byte(`{"error":"unavailable"}`),
+		},
 		err: clientErr,
 	}
 
 	service := NewCardService(client)
 
-	_, err := service.ConvertCardToIBAN(
+	result, err := service.ConvertCardToIBAN(
 		context.Background(),
 		"6037991234567890",
 	)
@@ -108,11 +124,20 @@ func TestCardServiceReturnsClientError(t *testing.T) {
 			clientErr,
 		)
 	}
+
+	if result.UpstreamHTTPStatus != 503 {
+		t.Errorf(
+			"ConvertCardToIBAN() status = %d, want 503",
+			result.UpstreamHTTPStatus,
+		)
+	}
 }
 
 func TestCardServicePassesContextToClient(t *testing.T) {
 	client := &fakeCardToIBANClient{
-		iban: "IR123456789012345678901234",
+		result: ConversionResult{
+			IBAN: "IR123456789012345678901234",
+		},
 	}
 
 	service := NewCardService(client)