Day1_HelloWorldMountebank.md

Day 1: Hello, World! mountebank

• The Problem with End-to-End Testing
• Setting up
  • 3A pattern: Arrange, Act, Assert, Cleanup
  • Imposters: virtual services, a lightweight operation
• Hello imposter
  • Run: [Command line]
  • List imposters: [curl, web browser]
• Create imposters: [Command line], file]
• Delete the imposter: [Command line]]
• Delete all imposters
• Saving multiple Imposters in the config file
• EJS: Embedded JavaScript

Setup Node.js(Windows)

• Goto Node.js downloads and download Node.js for Windows
  • LTS
  • Current
• Run the Node.js Installer(Windows)
  • Welcome to the Node.js setup wizard
    • Select Next
  • End-User License Agreement (EULA)
    • Check I accept the terms in the License Agreement
    • Select Next
  • Destination Folder
    • Select Next
  • Custom Setup
    • Select Next
  • Ready to install Node.js
    • Select Install
    • Note: This step requires Administrator privileges.
    • If prompted, authenticate as an Administrator.
  • Installing Node.js
    • Let the installer run to completion.
  • Completed the Node.js Setup Wizard
    • Click Finish

Setup Node.js(Mac)

• Install Homebrew

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

• Install Node.js

brew install node

Verify That Node.js was Properly Installed and Install Mountebank

• Run command

node -v

• Update npm

npm install npm -g

• Install mountebank

npm install mountebank -g

The Problem with End-to-End Testing

• Time
• Cost
• Slow feedback loop

3A pattern: Arrange, Act, Assert, Cleanup

• Setup data test
• Execute the system under test
• Assert the expected response
• Clean the state

Imposters: virtual services, a lightweight operation

• Mountebank provides configure virtual services, which are called imposters.
• Each imposter represents a socket that acts as the virtual service and accepts connections from the real service you are testing.
• Spinning up and shutting down imposters is a lightweight operation.

a simple Mountebank imposter

ref: Testing Microservice with Mountebank page 17

---

How mountebank views an HTTP request

ref: Testing Microservice with Mountebank page 26

POST /products?page=2&itemsPerPage=2 HTTP/1.1
Host: api.petstore.com
Content-Type: application/json

{
  "key": "asdul7890"
}

{
  "method": "POST",
  "path": "/products",
  "query": {
    "page": 2,
    "itemsPrePage": 2
  },
  "headers": {
    "Host": "api.petstore.com",
    "Content-Type": "application/json"
  },
  "body": "{\n  \"key\": \"asdul7890\"\n}"
}

How mountebank views an HTTP response

ref: Testing Microservice with Mountebank page 27

HTTP/1.1 200 OK
Date: Sun, 05 Apr 2020 10:10:10 GMT
Content-Type: application/json

{
  "key": "asdul7890"
}

{
  "statusCode": 200,
  "headers": {
    "Date": "Sun, 05 Apr 2020 10:10:10 GMT",
    "Content-Type": "application/json"
  },
  "body": "{\n  \"key\": \"asdul7890\"\n}"
}

The HTTP response structure in JSON

{
  "statusCode": 200,
  "headers": { "Content-Type": "text/plain" },
  "body": "Hello, World!"
}

---

Hello, World Mountebank

Run: [Command line]

mb

open web browser then go to http://localhost:2525

List imposters: [Command line, Web browser]

curl

curl http://localhost:2525/imposters

goto http://localhost:2525/imposters

Create First Imposters: [Command line]

curl

curl -X POST http://localhost:2525/imposters --data '
{
  "protocol": "http",
  "port": 3000,
  "stubs": [
    {
      "responses": [
        {
          "is": {
            "statusCode": 200,
            "headers": { "Content-Type": "text/plain" },
            "body": "Hello, World!"
          }
        }
      ]
    }
  ]
}'

Delete: [Command line]

curl

curl -X DELETE http://localhost:2525/imposters/3000

response

info: [mb:2525] DELETE /imposters/3000
info: [http:3000] Ciao for now

list imposters

curl http://localhost:2525/imposters

Delete all impostes

curl

curl -X DELETE http://localhost:2525/imposters

Create First Imposters from Config File

create file call hello-world.json

{
  "protocol": "http",
  "port": 3000,
  "stubs": [
    {
      "responses": [
        {
          "is": {
            "statusCode": 200,
            "headers": { "Content-Type": "text/plain" },
            "body": "Hello, World!"
          }
        }
      ]
    }
  ]
}

mb start --configfile hello-world.json

---

The Basic of Mountebank HTTP Responses

The is response type, which is the fundamental building block for a stub.

The HTTP response structure in JSON

{
  "statusCode": 200,
  "headers": { "Content-Type": "text/plain" },
  "body": "Hello, World!"
}

Default Response

{
  "protocol": "http",
  "port": 3001,
  "name": "Default Response",
  "defaultResponse": {
    "statusCode": 400,
    "headers": {
      "Connection": "Keep-Alive",
      "Content-Length": 0
    }
  },
  "stubs": [
    {
      "responses": [
        {
          "is": { "body": "BOOM!!!" }
        }
      ]
    }
  ]
}

Cycling through response

{
  "protocol": "http",
  "port": 3002,
  "stubs": [
    {
      "responses": [
        {
          "is": { "body": "1" }
        },
        {
          "is": { "body": "2" }
        },
        {
          "is": { "body": "3" }
        }
      ]
    }
  ]
}

---

Saving multiple Imposters in the config file

{
  "imposters": [
    {
      "protocol": "http",
      "port": 3000,
      "stubs": [
        {
          "responses": [
            {
              "is": {
                "statusCode": 200,
                "headers": { "Content-Type": "text/plain" },
                "body": "Hello, World!"
              }
            }
          ]
        }
      ]
    },
    {
      "protocol": "http",
      "port": 3001,
      "name": "Default Response",
      "defaultResponse": {
        "statusCode": 400,
        "headers": {
          "Connection": "Keep-Alive",
          "Content-Length": 0
        }
      },
      "stubs": [
        {
          "responses": [
            {
              "is": { "body": "BOOM!!!" }
            }
          ]
        }
      ]
    },
    {
      "protocol": "http",
      "port": 3002,
      "stubs": [
        {
          "responses": [
            { "is": { "body": "1" } },
            { "is": { "body": "2" } },
            { "is": { "body": "3" } }
          ]
        }
      ]
    }
  ]
}

imposter.ejs
hello-world.json
default-response.json
cycling-through-response.json

{
  "imposters": [
    <%- include hello-world.json %>,
    <%- include default-response.json %>,
    <%- include cycling-through-response.json %>,
  ]
}

EJS: Embedded JavaScript

Mountebank uses a templating language called EJS (https://ejs.co/)

---

Imposter Structure

{
  "port": <port>,
  "protocol": "http",
  "stubs": [
    {
      "predicates": [],
      "responses": [
        {
          "is": {
            "statusCode": <statusCode>,
            "headers": {},
            "body": {}
          }
        }
      ]
    }
  ]
}

Basic command and option

mb start --configfile hello-world.json --pidfile &

mb stop

mb restart  --configfile hello-world.json --pidfile &