MuleSoft MUnit OTP Email Test

This project demonstrates idiomatic MuleSoft development for OTP email verification testing using:

Mule Flows - Visual, declarative flow design
HTTP Connectors - Native Mule HTTP requests to MailSlurp API
DataWeave - Mule’s transformation language for data extraction
MUnit - MuleSoft’s native testing framework
Java Module - Selenium browser automation via Java invoke

Flow-Based Approach vs Plain Java

Aspect	This Project (Flow-Based)	Java-Only Approach
Structure	Visual Mule flows with connectors	Pure Java test classes
API Calls	Native HTTP Connector	MailSlurp Java SDK
Data Transform	DataWeave expressions	Java regex/parsing
Testing	MUnit test suites	JUnit tests
Visibility	Visual in Anypoint Studio	Code-only
Reusability	Flows can be reused/composed	Method calls

Benefits of Flow-Based Approach

Visual Design - See the flow in Anypoint Studio’s graphical editor
Native Connectors - Use Mule’s optimized HTTP connector
DataWeave Power - Elegant data transformation with less code
MUnit Testing - Test flows with mocking, assertions, coverage
Enterprise Ready - Easily add error handling, transactions, etc.

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                  otp-email-verification-flow                    │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  ┌─────────────┐    ┌──────────────────┐    ┌──────────────┐   │
│  │ HTTP POST   │───▶│ DataWeave        │───▶│ Java Invoke  │   │
│  │ /inboxes    │    │ Extract inbox ID │    │ Browser      │   │
│  └─────────────┘    │ & email address  │    │ Signup       │   │
│                     └──────────────────┘    └──────────────┘   │
│                                                     │          │
│                                                     ▼          │
│  ┌─────────────┐    ┌──────────────────┐    ┌──────────────┐   │
│  │ HTTP GET    │◀───│ Wait for email   │◀───│              │   │
│  │ /waitFor... │    │                  │    │              │   │
│  └─────────────┘    └──────────────────┘    └──────────────┘   │
│         │                                                      │
│         ▼                                                      │
│  ┌──────────────────┐    ┌──────────────┐    ┌─────────────┐   │
│  │ DataWeave        │───▶│ Java Invoke  │───▶│ Success     │   │
│  │ Extract OTP      │    │ Enter Code   │    │ Response    │   │
│  │ using regex      │    │ & Login      │    │             │   │
│  └──────────────────┘    └──────────────┘    └─────────────┘   │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Prerequisites

Java 8 or higher
Maven 3.6+
Google Chrome browser installed
MailSlurp API key (free at https://app.mailslurp.com)

Project Structure

mulesoft-anypoint-munit-otp-test/
├── pom.xml                                    # Maven config with MUnit
├── Makefile                                   # Build automation
├── README.md                                  # This file
├── mule-artifact.json                         # Mule app descriptor
├── src/
│   ├── main/
│   │   ├── mule/
│   │   │   └── otp-email-test-flow.xml       # Main Mule flow
│   │   ├── resources/
│   │   │   ├── config.yaml                   # Configuration properties
│   │   │   └── log4j2.xml                    # Logging config
│   │   └── java/
│   │       └── com/smoketest/selenium/
│   │           └── BrowserHelper.java        # Selenium helper class
│   └── test/
│       ├── munit/
│       │   └── otp-email-test-suite.xml      # MUnit test suite
│       └── resources/
│           └── log4j2-test.xml               # Test logging config

Configuration

Environment Variable (Recommended)

export MAILSLURP_API_KEY=your_api_key_here

Using .env File

Create ../.env (parent directory) with:

MAILSLURP_API_KEY=your_api_key_here

The Makefile will automatically load this.

Direct Configuration (Not Recommended)

Edit src/main/resources/config.yaml:

mailslurp:
  apiKey: "your_api_key_here"

Running Tests

Using Make (Recommended)

# Show available commands
make help

# Run all tests
make test

# Run MUnit tests specifically
make test_munit

# Run with verbose output
make test_verbose

# Clean build
make clean

Using Maven Directly

# Run all tests
MAILSLURP_API_KEY=your_key mvn test

# Run MUnit tests
mvn test -Dmunit.test=otp-email-test-suite

# Run with specific test
mvn test -Dmunit.test=otp-email-test-suite#otp-email-verification-flow-test

Opening in Anypoint Studio

File → Import
Select Anypoint Studio → Anypoint Studio project from File System
Browse to this directory
Click Finish

The flow will appear in the visual designer where you can:

See the flow structure graphically
Click on any component to view/edit its configuration
Run/debug flows directly
Execute MUnit tests with coverage

Test Flow Description

The otp-email-verification-flow performs:

Create Inbox - HTTP POST to MailSlurp API creates a real email inbox
Extract Details - DataWeave extracts inboxId and emailAddress
Browser Signup - Java invoke opens Chrome, fills signup form
Wait for Email - HTTP GET to MailSlurp waits for verification email
Extract OTP - DataWeave regex extracts 6-digit code from email body
Verify & Login - Java invoke enters code, logs in, asserts “Welcome”
Return Success - JSON response with test results

DataWeave OTP Extraction

The OTP code is extracted using DataWeave’s regex capabilities:

%dw 2.0
import * from dw::core::Strings
var emailBody = payload.body
var codeMatch = emailBody scan /([0-9]{6})$/
---
if (sizeOf(codeMatch) > 0) codeMatch[0][1] else null

MUnit Test Assertions

The MUnit test validates:

success is true
otpCodeVerified is true
emailAddress is present
inboxId is present

Error Handling

The flow includes comprehensive error handling:

Browser is closed on any error
Error response includes type, description, and details
All errors are logged

Dependencies

Dependency	Version	Purpose
Mule HTTP Connector	1.10.3	API requests
Mule Java Module	1.2.13	Java invoke
MUnit Runner	3.3.1	Test execution
MUnit Tools	3.3.1	Assertions
Selenium	4.18.1	Browser automation

Troubleshooting

API Key Not Set

ERROR: MAILSLURP_API_KEY environment variable is not set

→ Set the environment variable or create .env file

Chrome Not Found

Cannot find Chrome binary

→ Install Google Chrome browser

MUnit Tests Timeout

→ Increase timeout in config.yaml or MUnit test configuration

Flow Not Found in Studio

→ Ensure you imported as “Anypoint Studio project from File System”

mulesoft-anypoint-java-selenium-test - Plain Java/JUnit approach

License

This project is for demonstration purposes as part of MuleSoft Anypoint testing examples.