給定以下用 Go 編寫的簡單 lambda，它只返回一個表描述...package mainimport ( "context" "encoding/json" "fmt" "log" "net/http" "os" "strings" "github.com/aws/aws-lambda-go/events" "github.com/aws/aws-lambda-go/lambda" "github.com/aws/aws-sdk-go-v2/aws" "github.com/aws/aws-sdk-go-v2/config" "github.com/aws/aws-sdk-go-v2/service/dynamodb" "go.uber.org/zap")var ( dynamoDBTableName = aws.String(os.Getenv(EnvDynamoDBTableName)) logger = func() *zap.Logger { l, err := zap.NewProduction() if err != nil { log.Printf("failed to create zap logger: %v", err) } return l }())func handler(ctx context.Context, req events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) { defer logger.Sync() resp := events.APIGatewayProxyResponse{} cfg, err := config.LoadDefaultConfig(ctx) if err != nil { logger.Error("failed to load AWS config", zap.Error(err)) return resp, fmt.Errorf("failed to load AWS config: %w", err) } svc := dynamodb.NewFromConfig(cfg) // fake logic t, err := svc.DescribeTable(ctx, &dynamodb.DescribeTableInput{TableName: dynamoDBTableName}) if err != nil { logger.Error("failed to describe table", zap.String("table-name", *dynamoDBTableName), zap.Error(err)) } var sb strings.Builder enc := json.NewEncoder(&sb) err = enc.Encode(t.Table) if err != nil { logger.Error("failed to JSON encode response", zap.Error(err)) } resp.Body = sb.String() resp.StatusCode = http.StatusOK return resp, nil}func main() { lambda.Start(handler)}...如何在本地對其進行單元測試？使用舊的SDK，可以使用如下依賴注入：type deps struct svc dynamodbiface.DynamoDBAPI table string}func (d *deps) handler(ctx context.Context, req events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) { ...}如何測試使用新的適用于 Go V2 的 AWS 開發工具包編寫的 lambda，因為我需要上下文來加載所需的配置？dynamodb.NewFromConfig
1 回答
犯罪嫌疑人X
TA貢獻2080條經驗 獲得超4個贊
首先，使你的處理程序成為一個不起眼的對象，這樣我們就可以“跳過”測試它：
func handler(ctx context.Context, req events.APIGatewayProxyRequest)
(events.APIGatewayProxyResponse, error) {
dynamoWrapper := &RealDynamoWrapper{}
proxyController := &ProxyController{DynamoWrapper: dynamoWrapper}
return proxyController.proxy(ctx, req)
這個想法是使處理程序函數變得謙卑，方法是讓它將所有復雜性委托給 .proxyController
現在，讓我們考慮要測試的，我們需要先定義它：ProxyController
type ProxyController struct {
dynamoWrapper DynamoWrapper
}
func(controller *ProxyController) Proxy(ctx context.Context, req events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
// this is where your implementation lives that you need to mock stuff for
// We are mocking this line from your question
svc := controller.dynamoWrapper.NewFromConfig(...)
// do other stuff and then return something
return events.APIGatewayProxyResponse{}, nil
}
你可以看到我將依賴于一個包裝版本的dynamo，它看起來像這樣：
type DynamoWrapper interface {
NewFromConfig(cfg aws.Config, optFns ...func(*Options)) *Client
}
現在，此包裝器的真正實現，上面引用的那個將像對 sdk 執行操作一樣進行調用。但是，對于我們的測試，我們想要一個模擬實現：RealDynamoWrapper
type mockDynamoWrapper struct {
NewFromConfigFunc func(aws.Config, ...func(*Options)) *Client
}
func(dynamoWrapper *mockDynamoWrapper) NewFromConfig(cfg aws.Config, optFns ...func(*Options)) *Client {
return dynamoWrapper.NewFromConfigFunc(cfg, optFns...)
}
最后，在測試中，您現在可以模擬發電機調用：
func TestProxyController(t *testing.T) {
// given
dynamoWrapper := &mockDynamoWrapper{}
proxyController := &ProxyController{DynamoWrapper: mockDynamoWrapper}
request := events.APIGatewayProxyRequest{}
dynamoWrapper.NewFromConfigFunc = func(aws.Config, ...func(*Options)) *Client {
// setup your mock function to do whatever you want
}
// when
proxyController.proxy(context.Background, request)
// then do your asserts
}
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