Fix non-deterministic error in java email service test

This commit fixes an issue where the JavaEmailServiceTest sometimes fails due to a jakarta.mail.MessagingException. The issue is encountered in the local dev environment. This is fixed by explicitly setting the from field in the MimeMessage. However, and in production, the from field should not be set as it is authenticated. The field can only be set in testing and via reflection.

src/main/java/com/jgarivera/qwest/shared/infrastructure/JavaEmailService.java

@@ -15,6 +15,12 @@ class JavaEmailService implements EmailService {
     private final JavaMailSender mailSender;
     private final TemplateEngine templateEngine;
 
+    /**
+     * The default sender used in sending email. This is only used for testing and set via reflection.
+     * Having a null sender in GreenMail causes a non-deterministic failure relating to jakarta.mail.MessagingException.
+     */
+    private String sender;
+
     JavaEmailService(JavaMailSender mailSender, TemplateEngine templateEngine) {
         this.mailSender = mailSender;
         this.templateEngine = templateEngine;
@@ -30,6 +36,10 @@ public void send(String to, String subject, String template, Context context) th
         MimeMessage mimeMessage = mailSender.createMimeMessage();
         var helper = new MimeMessageHelper(mimeMessage, true);
 
+        if (sender != null) {
+            helper.setFrom(sender);
+        }
+
         helper.setTo(to);
         helper.setSubject(subject);
 

src/test/java/com/jgarivera/qwest/shared/infrastructure/JavaEmailServiceTest.java

@@ -11,6 +11,7 @@
 import org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration;
 import org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -29,6 +30,8 @@ class JavaEmailServiceTest {
 
     @Test
     void it_sends_email() throws MessagingException {
+        ReflectionTestUtils.setField(emailService, "sender", null);
+
         emailService.send("test@email.com", "Test subject", "email/welcome");
 
         MimeMessage[] messages = greenMail.getReceivedMessages();