Add refund transaction API

Author: AchoArnold

README.md

@@ -27,10 +27,13 @@ import "github.com/NdoleStudio/flutterwave-go"
 
 ## Implemented
 
-- [Status Codes](#bills)
-    - `POST /bills/`: Create a bill payment
-    - `GET /bill-items/{item_code}/validate`: Validate services like DSTV smartcard number, Meter number etc.
-    - `GET /bills/{reference}`: Get the verbose status of a bill payment
+- **[Bills](#bills)**
+  - `POST /bills/`: Create a bill payment
+  - `GET /bill-items/{item_code}/validate`: Validate services like DStv smartcard number, Meter number etc.
+  - `GET /bills/{reference}`: Get the verbose status of a bill payment
+- **Payments**
+  - `GET /v3/transactions/:id/verify`: Verify a transaction
+  - `POST /v3/transactions/:id/refund`: Create a Refund
 
 ## Usage
 
@@ -46,7 +49,7 @@ import (
 )
 
 func main()  {
-	flutterwaveClient := flutterwave.New(
+	client := flutterwave.New(
 		flutterwave.WithSecretKey("" /* flutterwave Secret Key */),
 	)
 }

bills_service_models.go renamed to bills.go

@@ -64,3 +64,27 @@ func BillsGetStatusVerboseResponse() string {
 	}
 `
 }
+
+// TransactionRefundResponse is a dummy response for refunding a transaction
+func TransactionRefundResponse() []byte {
+	return []byte(`
+{
+  "status": "success",
+  "message": "Transaction refund initiated",
+  "data": {
+    "id": 75923,
+    "account_id": 73362,
+    "tx_id": 908790,
+    "flw_ref": "URF_1577867664541_3572735",
+    "wallet_id": 74639,
+    "amount_refunded": 6900,
+    "status": "completed",
+    "destination": "payment_source",
+    "meta": {
+      "source": "availablebalance"
+    },
+    "created_at": "2021-01-24T09:18:37.366Z"
+  }
+}
+`)
+}

internal/stubs/api_responses.go

@@ -44,3 +44,23 @@ type TransactionResponse struct {
 		} `json:"customer"`
 	} `json:"data"`
 }
+
+// RefundTransactionResponse is the payload generated when a transaction is refunded
+type RefundTransactionResponse struct {
+	Status  string `json:"status"`
+	Message string `json:"message"`
+	Data    struct {
+		ID             int    `json:"id"`
+		AccountID      int    `json:"account_id"`
+		TxID           int    `json:"tx_id"`
+		FlwRef         string `json:"flw_ref"`
+		WalletID       int    `json:"wallet_id"`
+		AmountRefunded int    `json:"amount_refunded"`
+		Status         string `json:"status"`
+		Destination    string `json:"destination"`
+		Meta           struct {
+			Source string `json:"source"`
+		} `json:"meta"`
+		CreatedAt time.Time `json:"created_at"`
+	} `json:"data"`
+}

transactions.go

@@ -33,3 +33,27 @@ func (service *transactionsService) Verify(ctx context.Context, transactionID in
 
 	return &data, response, nil
 }
+
+// Refund a transaction
+//
+// API Docs: https://developer.flutterwave.com/reference/endpoints/transactions/#create-a-refund
+func (service *transactionsService) Refund(ctx context.Context, transactionID int64, amount int32) (*RefundTransactionResponse, *Response, error) {
+	uri := fmt.Sprintf("/v3/transactions/%d/refund", transactionID)
+
+	request, err := service.client.newRequest(ctx, http.MethodPost, uri, map[string]int32{"amount": amount})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	response, err := service.client.do(request)
+	if err != nil {
+		return nil, response, err
+	}
+
+	var data RefundTransactionResponse
+	if err = json.Unmarshal(*response.Body, &data); err != nil {
+		return nil, response, err
+	}
+
+	return &data, response, nil
+}

transactions_service.go

@@ -0,0 +1,52 @@
+package flutterwave
+
+import (
+	"context"
+	"github.com/NdoleStudio/flutterwave-go/internal/helpers"
+	"github.com/NdoleStudio/flutterwave-go/internal/stubs"
+	"github.com/stretchr/testify/assert"
+	"net/http"
+	"testing"
+)
+
+func TestTransactionsService_Refund(t *testing.T) {
+	// Setup
+	t.Parallel()
+
+	// Arrange
+	server := helpers.MakeTestServer(http.StatusOK, string(stubs.TransactionRefundResponse()))
+	client := New(WithBaseURL(server.URL))
+
+	// Act
+	refund, response, err := client.Transactions.Refund(context.Background(), 123, 200)
+
+	// Assert
+	assert.Nil(t, err)
+
+	assert.Equal(t, http.StatusOK, response.HTTPResponse.StatusCode)
+	assert.Equal(t, stubs.TransactionRefundResponse(), *response.Body)
+	assert.Equal(t, 75923, refund.Data.ID)
+
+	// Teardown
+	server.Close()
+}
+
+func TestTransactionsService_RefundWithError(t *testing.T) {
+	// Setup
+	t.Parallel()
+
+	// Arrange
+	server := helpers.MakeTestServer(http.StatusInternalServerError, "")
+	client := New(WithBaseURL(server.URL))
+
+	// Act
+	_, response, err := client.Transactions.Refund(context.Background(), 123, 200)
+
+	// Assert
+	assert.NotNil(t, err)
+
+	assert.Equal(t, http.StatusInternalServerError, response.HTTPResponse.StatusCode)
+
+	// Teardown
+	server.Close()
+}