How to test email and SMS in Java

1. Create a Mailosaur account

If you already have an account, skip to step 2.

To create a new trial account, sign up here.

2. Create a sample project

This guide makes use of JUnit, therefore create an empty Java & JUnit project to begin.

Install the Mailosaur Java library

Gradle users can add this dependency to their project’s build file:

// MAILOSAUR_JAVA_VERSION available at:
// https://github.com/mailosaur/mailosaur-java/releases/latest)
implementation "com.mailosaur:mailosaur-java:MAILOSAUR_JAVA_VERSION"

Maven users should add this dependency to your project’s POM:

<dependency>
  <groupId>com.mailosaur</groupId>
  <artifactId>mailosaur-java</artifactId>
  <version>MAILOSAUR_JAVA_VERSION</version>
</dependency>

If you don’t use Gradle or Maven, refer to the README within the GitHub repository.

3. Send email to your Mailosaur inbox

Inboxes allow you to group tests, permissions, and other settings together. Each inbox has an Inbox ID and a domain name. You need these values to both send email to Mailosaur, and to set up automated testing.

You also need an API key to use. You can learn more about creating API keys here.

Retrieve your inbox’s attributes

1. In the left-hand navigation, locate the Inboxes section.
2. Click on the name of the inbox you want to test with.
3. Click on the API tab.
4. Make a note of the Inbox ID, domain name and API key.

Send an email to your inbox

If the domain name of your inbox above was:

example.mailosaur.net

Then you can send an email to it with these steps:

1. Open up an email client and send an email to anything@example.mailosaur.net
2. In the left-hand navigation, locate the Inboxes section.
3. Click on the name of the inbox you sent an email to.
4. Confirm the email is there. Note that some services (like Gmail) may take 10-20 seconds to send a message through.

To learn more, read our guide on sending email to Mailosaur.

4. Find an email for automated testing

Now that you have a sample project, your inbox’s credentials, and an email to test, then you’re ready to continue.

Open the file containing tests in your new, sample project (e.g. AppTest.java) and type or paste in this code sample, replacing the template code with the values from step 3 above:

package demo;

import org.junit.Test;
import static org.junit.Assert.*;
import com.mailosaur.MailosaurClient;
import com.mailosaur.MailosaurException;
import com.mailosaur.models.*;
import java.io.IOException;

public class AppTest {
  @Test public void testExample() throws IOException, MailosaurException {
    // Available in the API tab of an inbox
    String apiKey = "YOUR_API_KEY";
    String serverId = "SERVER_ID";
    String serverDomain = "SERVER_DOMAIN";

    MailosaurClient mailosaur = new MailosaurClient(apiKey);

    MessageSearchParams params = new MessageSearchParams();
    params.withServer(serverId);

    SearchCriteria criteria = new SearchCriteria();
    criteria.withSentTo("asdas@" + serverDomain);

    Message message = mailosaur.messages().get(params, criteria);

    assertNotNull(message);
    assertEquals("My email subject", message.subject());
  }
}

This code connects to Mailosaur and looks for any email that has been sent to the address provided in the search criteria.

Save your changes and run your tests.

If everything is set up correctly, you should see tests run and the subject line of the last email you sent will be checked.

Troubleshooting

If you see an error, e.g. ‘No matching messages found in time’:

• Make sure you have set the sent to address correctly in your code.
• Ensure that you have sent an email to the sent to address (check this is visible in the Mailosaur Dashboard).
• Note that by default, the get method will only look for messages that were received by Mailosaur within the last hour. You can override this using the receivedAfter option (see library reference below).

5. Narrowing your search results

Only find messages received after a certain time

By default, searches include messages received in the last hour, but you can customise the search window with the receivedAfter option.

This example shows you how to only include emails received after your test started:

Date testStart = System.currentTimeMillis();

// Perform the steps that send a message here

MessageSearchParams params = new MessageSearchParams();
params.withServer(serverId)
  .withReceivedAfter(testStart);

SearchCriteria criteria = new SearchCriteria();
criteria.withSentTo("...");

Message message = mailosaur.messages().get(params, criteria);

Search criteria

As you can see in the examples so far, you can search for the email address or phone number a message was sent to, but you can also search using these criteria:

6. Start writing tests

Now that you have a working project that fetches an email, you can use this to begin writing tests for various pieces of functionality.

Check out these guides on the most common test cases:

SMS Testing

You can test SMS messages in much the same way as email. Take a look at our guide on testing SMS messages for more information.

Library reference

The Java client library gives you access to several other methods.

Messages

Messages is the collective name given to the email and/or SMS messages that are sent into Mailosaur for testing. The message object contains everything you need to perform in-depth automated testing.

messages.get(MessageSearchParams, SearchCriteria)

Waits for a message to be found. Returns as soon as a message matching the specified search criteria is found.

Recommended: This is the most efficient method of looking up a message, therefore we recommend using it wherever possible.

MessageSearchParams params = new MessageSearchParams();
params.withServer("SERVER_ID");

SearchCriteria criteria = new SearchCriteria();
criteria.withSentTo("someone@SERVER_ID.mailosaur.net");

Message message = mailosaur.messages().get(params, criteria);

To learn about inbox IDs, and what to replace SERVER_ID with, see sending email to Mailosaur.

Criteria

Options

MessageSearchParams params = new MessageSearchParams();
params.withServer("SERVER_ID")
  withReceivedAfter(1578182400000L);

SearchCriteria criteria = new SearchCriteria();
criteria.withSentTo("someone@SERVER_ID.mailosaur.net");

// Search all messages received after midnight on a specific date
Message message = mailosaur.messages().get(params, criteria);

messages.list(MessageListParams)

Returns a list of your messages in summary form. The summaries are returned sorted by received date, with the most recently-received messages appearing first.

// List the most recent messages
MessageListParams params = new MessageListParams();
params.withServer("SERVER_ID");
MessageListResult result = mailosaur.messages().list(params);

// Get the most recent message (the first one in the list)
MessageSummary message = result.items().get(0);

System.out.println("Subject: " + message.subject());

Options

• receivedAfter Allows you to customise how far back to look for messages (time in milliseconds).
• page Used alongside itemsPerPage to paginate through results. This is zero-based, meaning 0 is the first page of results.
• itemsPerPage A limit on the number of results to be returned. This can be set between 1 to 1000, with the default being 50.
• dir Optionally limits results based on the direction (Sent or Received), with the default being Received.

// List all results received after midnight on a specific date
MessageListParams params = new MessageListParams();
params.withServer("SERVER_ID").withReceivedAfter(1577836800000L);
MessageListResult result = mailosaur.messages().list(params);

messages.search(MessageSearchParams, SearchCriteria)

Returns a list of messages matching the specified search criteria, in summary form. The messages are returned sorted by received date, with the most recently-received messages appearing first.

MessageSearchParams params = new MessageSearchParams();
params.withServer("SERVER_ID");

SearchCriteria criteria = new SearchCriteria();
criteria.withSentTo("someone@SERVER_ID.mailosaur.net");

MessageListResult result = mailosaur.messages().search(params, criteria);

// Get the most recent match
MessageSummary message = result.items().get(0);

System.out.println("Subject: " + message.subject());

Criteria

• sentFrom The full email address from which the target message was sent.
• sentTo The full email address to which the target message was sent.
• subject The subject line of the target email.
• body Search for part of the message body.
• match If set to ALL (default), then only results that match all specified criteria will be returned. If set to ANY, results that match any of the specified criteria will be returned.

Options

• timeout If provided, determines how long to wait for a matching result (provided in milliseconds).
• errorOnTimeout When set to false, an error will not be thrown if timeout is reached (default: true).
• receivedAfter Allows you to customise how far back to look for messages (time in milliseconds).
• page Used alongside itemsPerPage to paginate through results. This is zero-based, meaning 0 is the first page of results.
• itemsPerPage A limit on the number of results to be returned. This can be set between 1 to 1000, with the default being 50.
• dir Optionally limits results based on the direction (Sent or Received), with the default being Received.

// Search for all messages sent to someone@SERVER_ID.mailosaur.net.
// Limit results to the first 10 matches only.
MessageSearchParams params = new MessageSearchParams();
params.withServer("SERVER_ID")
  .withPage(0)
  .withItemsPerPage(10);

MessageListResult result = mailosaur.messages().search(params, criteria);

messages.getById(id)

Retrieves the detail for a single email message. Must be used in conjunction with either list or search in order to get the unique identifier for the required message. We always recommend using the get method instead.

MessageListParams params = new MessageListParams();
params.withServer("SERVER_ID");
MessageListResult result = mailosaur.messages().list(params);
String messageId = result.items().get(0).id();

Message message = mailosaur.messages().getById(messageId);

System.out.println("Subject: " + message.subject());

messages.delete(id)

Permanently deletes a message. Also deletes any attachments related to the message. This operation cannot be undone.

mailosaur.messages().delete(messageId);

messages.deleteAll(server)

Permanently deletes all messages held in the specified inbox. Also deletes any attachments related to each message. This operation cannot be undone.

mailosaur.messages().deleteAll("SERVER_ID");

messages.create(server, messageCreateOptions)

Creates a new message that can be sent to a verified email address. This is useful in scenarios where you want an email to trigger a workflow in your product.

MessageCreateOptions options = new MessageCreateOptions();
options.withTo("verified-address@example.com")
  .withSend(true)
  .withSubject("Request")
  .withText("Please can you give us a call back?");

mailosaur.messages().create("SERVER_ID", options);

Options

• to The email address to which the email will be sent. Must be a verified email address.
• send If true, email will be sent upon creation.
• subject The email subject line.
• text The plain text body of the email.
• html The HTML body of the email.

messages.forward(messageId, messageForwardOptions)

Forwards the specified email to a verified email address.

MessageForwardOptions options = new MessageForwardOptions();
options.withTo("verified-address@example.com")
  .withText("FYI");

mailosaur.messages().forward("MESSAGE_ID", options);

Options

• to The email address to which the email will be sent. Must be a verified email address.
• text Any additional plain text content to forward the email with.
• html Any additional HTML content to forward the email with.

messages.reply(messageId, messageReplyOptions)

Sends a reply to the specified email. This is useful for when simulating a user replying to one of your emails.

MessageReplyOptions options = new MessageReplyOptions();
options.withText("FYI");

mailosaur.messages().reply("MESSAGE_ID", options);

Options

• text Any additional plain text content to include in the reply.
• html Any additional HTML content to include in the reply.

Servers

Inboxes capture emails and SMS messages, group your tests and settings, and manage access for your team.

servers.list()

Returns a list of your inboxes. Inboxes are returned sorted in alphabetical order.

ServerListResult result = mailosaur.servers().list();

System.out.println("You have an inbox called: " + result.items().get(0).name());

servers.create(server)

Creates a new inbox. Only the name property is required to create a new inbox via the API.

ServerCreateOptions options = new ServerCreateOptions().withName("My email tests");
mailosaur.servers().create(options);

servers.get(id)

Retrieves the detail for a single inbox. Simply supply the unique identifier for the required inbox.

Server server = mailosaur.servers().get("SERVER_ID");

servers.getPassword(id)

Retrieves the password, for use with SMTP and POP3, for a single inbox. Simply supply the unique identifier for the required inbox.

String password = mailosaur.servers().getPassword("SERVER_ID");

servers.update(id, server)

Updates a single inbox.

Server retrievedServer = mailosaur.servers().get("SERVER_ID");
retrievedServer.withName("Updated inbox name");

mailosaur.servers().update(retrievedServer.id(), retrievedServer);

servers.del(id)

Permanently deletes an inbox. Also deletes all messages and associated attachments within the inbox. This operation cannot be undone.

mailosaur.servers().delete("SERVER_ID");

servers.generateEmailAddress(id)

Utility method to help you generate a random email address for a given inbox.

String emailAddress = mailosaur.servers().generateEmailAddress("SERVER_ID");

System.out.println(emailAddress); // "bgwqj@SERVER_ID.mailosaur.net"

To learn about inbox IDs, and what to replace SERVER_ID with, see sending email to Mailosaur.

Files

files.getEmail(messageId)

Downloads an EML file representing the specified email. Simply supply the unique identifier for the required email.

files.getAttachment(attachmentId)

Downloads a single attachment. Simply supply the unique identifier for the required attachment.

Analysis

analysis.spam(messageId)

Perform spam testing on the specified email.

Usage

usage.limits()

Retrieve account usage limits. Details the current limits and usage for your account. This endpoint requires authentication with an account-level API key.

usage.transactions()

Retrieves the last 31 days of transactional usage. This endpoint requires authentication with an account-level API key.