Chapter 10: Testing Your Serverless Application

1. Write a unit test for the UpdateMovie Lambda function.Answer:

package main

import (
  "testing"

  "github.com/stretchr/testify/assert"

  "github.com/aws/aws-lambda-go/events"
)

func TestUpdate_InvalidPayLoad(t *testing.T) {
  input := events.APIGatewayProxyRequest{
    Body: "{'name': 'avengers'}",
  }
  expected := events.APIGatewayProxyResponse{
    StatusCode: 400,
    Body: "Invalid payload",
  }
  response, _ := update(input)
  assert.Equal(t, expected, response)
}

func TestUpdate_ValidPayload(t *testing.T) {
  input := events.APIGatewayProxyRequest{
    Body: "{\"id\":\"40\", \"name\":\"Thor\", \"description\":\"Marvel movie\", \"cover\":\"poster url\"}",
  }
  expected := events.APIGatewayProxyResponse{
    Body: "{\"id\":\"40\", \"name\":\"Thor\", \"description\":\"Marvel movie\", \"cover\":\"poster url\"}",
    StatusCode: 200,
    Headers: map[string]string{
      "Content-Type": "application/json",
      "Access-Control-Allow-Origin": "*",
    },
  }
  response, _ := update(input)
  assert.Equal(t, expected, response)
}

2. Write a unit test for the DeleteMovie Lambda function.Answer:

package main

import (
  "testing"

  "github.com/stretchr/testify/assert"

  "github.com/aws/aws-lambda-go/events"
)

func TestDelete_InvalidPayLoad(t *testing.T) {
  input := events.APIGatewayProxyRequest{
    Body: "{'name': 'avengers'}",
  }
  expected := events.APIGatewayProxyResponse{
    StatusCode: 400,
    Body: "Invalid payload",
  }
  response, _ := delete(input)
  assert.Equal(t, expected, response)
}

func TestDelete_ValidPayload(t *testing.T) {
  input := events.APIGatewayProxyRequest{
    Body: "{\"id\":\"40\", \"name\":\"Thor\", \"description\":\"Marvel movie\", \"cover\":\"poster url\"}",
  }
  expected := events.APIGatewayProxyResponse{
    StatusCode: 200,
    Headers: map[string]string{
      "Content-Type": "application/json",
      "Access-Control-Allow-Origin": "*",
    },
  }
  response, _ := delete(input)
  assert.Equal(t, expected, response)
}

3. Modify the Jenkinsfile provided in previous chapters to include the execution of automated unit tests.

Answer: Note the usage of go test command in the Test stage:

def bucket = 'movies-api-deployment-packages'

node('slave-golang'){
  stage('Checkout'){
    checkout scm
  }

  stage('Test'){
    sh 'go get -u github.com/golang/lint/golint'
    sh 'go get -t ./...'
    sh 'golint -set_exit_status'
    sh 'go vet .'
    sh 'go test .'
  }

  stage('Build'){
    sh 'GOOS=linux go build -o main main.go'
    sh "zip ${commitID()}.zip main"
  }

  stage('Push'){
    sh "aws s3 cp ${commitID()}.zip s3://${bucket}"
  }

  stage('Deploy'){
    sh "aws lambda update-function-code --function-name FindAllMovies \
      --s3-bucket ${bucket} \
      --s3-key ${commitID()}.zip \
      --region us-east-1"
  }
}

def commitID() {
  sh 'git rev-parse HEAD > .git/commitID'
  def commitID = readFile('.git/commitID').trim()
  sh 'rm .git/commitID'
  commitID
}

4. Modify the buildspec.yml definition file to include the execution of unit tests, before pushing the deployment package to S3 using AWS CodeBuild.Answer:

version: 0.2
env:
  variables:
    S3_BUCKET: "movies-api-deployment-packages"
    PACKAGE: "github.com/mlabouardy/lambda-codepipeline"

phases:
  install:
    commands:
      - mkdir -p "/go/src/$(dirname ${PACKAGE})"
      - ln -s "${CODEBUILD_SRC_DIR}" "/go/src/${PACKAGE}"
      - go get -u github.com/golang/lint/golint

  pre_build:
    commands:
      - cd "/go/src/${PACKAGE}"
      - go get -t ./...
      - golint -set_exit_status
      - go vet .
      - go test .

  build:
    commands:
      - GOOS=linux go build -o main
      - zip $CODEBUILD_RESOLVED_SOURCE_VERSION.zip main
      - aws s3 cp $CODEBUILD_RESOLVED_SOURCE_VERSION.zip s3://$S3_BUCKET/

  post_build:
    commands:
      - aws lambda update-function-code --function-name FindAllMovies --s3-bucket $S3_BUCKET --s3-key $CODEBUILD_RESOLVED_SOURCE_VERSION.zip

5. Write a SAM template file for each Lambda function implemented in previous chapters.

Answer: The following is a SAM template file for the FindAllMovies Lambda function; the same resources can be used to create other functions:

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Parameters:
  StageName:
    Type: String
    Default: staging
    Description: The API Gateway deployment stage

Resources:
  FindAllMovies:
    Type: AWS::Serverless::Function
    Properties:
      Handler: main
      Runtime: go1.x
      Role: !GetAtt FindAllMoviesRole.Arn 
      CodeUri: ./findall/deployment.zip
      Environment:
        Variables: 
          TABLE_NAME: !Ref MoviesTable
      Events:
        AnyRequest:
          Type: Api
          Properties:
            Path: /movies
            Method: GET
            RestApiId:
              Ref: MoviesAPI

  FindAllMoviesRole:
   Type: "AWS::IAM::Role"
   Properties:
     Path: "/"
     ManagedPolicyArns:
         - "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
     AssumeRolePolicyDocument:
       Version: "2012-10-17"
       Statement:
         -
           Effect: "Allow"
           Action:
             - "sts:AssumeRole"
           Principal:
             Service:
               - "lambda.amazonaws.com"
     Policies: 
        - 
          PolicyName: "PushCloudWatchLogsPolicy"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: Allow
                Action:
                - logs:CreateLogGroup
                - logs:CreateLogStream
                - logs:PutLogEvents
                Resource: "*"
        - 
          PolicyName: "ScanDynamoDBTablePolicy"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: Allow
                Action:
                - dynamodb:Scan
                Resource: "*"

  MoviesTable: 
     Type: AWS::Serverless::SimpleTable
     Properties:
       PrimaryKey:
         Name: ID
         Type: String
       ProvisionedThroughput:
         ReadCapacityUnits: 5
         WriteCapacityUnits: 5

  MoviesAPI:
    Type: 'AWS::Serverless::Api'
    Properties:
      StageName: !Ref StageName
      DefinitionBody:
        swagger: 2.0
        info:
          title: !Sub API-${StageName}
        paths:
          /movies:
            x-amazon-apigateway-any-method:
              produces:
                - application/json
              x-amazon-apigateway-integration:
                uri:
                  !Sub "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${FindAllMovies.Arn}:current/invocations"
                passthroughBehavior: when_no_match
                httpMethod: POST
                type: aws_proxy