//! Contact form endpoint for handling user submissions and sending emails. //! //! This module provides functionality to: //! - Validate contact form submissions //! - Detect spam using honeypot fields //! - Send emails via SMTP with various TLS configurations use lettre::{ Message, SmtpTransport, Transport, message::header::ContentType, transport::smtp::authentication::Credentials, }; use poem_openapi::{ApiResponse, Object, OpenApi, payload::Json}; use validator::Validate; use super::ApiCategory; use crate::settings::{EmailSettings, Starttls}; pub mod errors; use errors::ContactError; impl TryFrom<&EmailSettings> for SmtpTransport { type Error = lettre::transport::smtp::Error; fn try_from(settings: &EmailSettings) -> Result { if settings.tls { // Implicit TLS (SMTPS) - typically port 465 tracing::event!(target: "backend::contact", tracing::Level::DEBUG, "Using implicit TLS (SMTPS)"); let creds = Credentials::new(settings.user.clone(), settings.password.clone()); Ok(Self::relay(&settings.host)? .port(settings.port) .credentials(creds) .build()) } else { // STARTTLS or no encryption match settings.starttls { Starttls::Never => { // For local development without TLS tracing::event!(target: "backend::contact", tracing::Level::DEBUG, "Using unencrypted connection"); let builder = Self::builder_dangerous(&settings.host).port(settings.port); if settings.user.is_empty() { Ok(builder.build()) } else { let creds = Credentials::new(settings.user.clone(), settings.password.clone()); Ok(builder.credentials(creds).build()) } } Starttls::Opportunistic | Starttls::Always => { // STARTTLS - typically port 587 tracing::event!(target: "backend::contact", tracing::Level::DEBUG, "Using STARTTLS"); let creds = Credentials::new(settings.user.clone(), settings.password.clone()); Ok(Self::starttls_relay(&settings.host)? .port(settings.port) .credentials(creds) .build()) } } } } } #[derive(Debug, Object, Validate)] struct ContactRequest { #[validate(length(min = 1, max = "100", code = "name"))] name: String, #[validate(email(code = "email"))] email: String, #[validate(length(min = 10, max = 5000, code = "message"))] message: String, /// Honeypot field - should always be empty #[oai(rename = "website")] honeypot: Option, } impl TryFrom<&ContactRequest> for lettre::message::Mailbox { type Error = ContactError; fn try_from(value: &ContactRequest) -> Result { value.email.parse().map_or_else( |_| { Err(ContactError::CouldNotParseRequestEmailAddress( value.email.clone(), )) }, |email| { Ok(Self { name: Some(value.name.clone()), email, }) }, ) } } #[derive(Debug, Object, serde::Deserialize)] struct ContactResponse { success: bool, message: String, } impl From for Json { fn from(value: ContactResponse) -> Self { Self(value) } } impl ContactResponse { pub fn success() -> Self { Self { success: true, message: "backend.contact.success".to_owned(), } } pub fn honeypot_response() -> Self { Self { success: true, message: "backend.contact.honeypot".to_owned(), } } } #[derive(ApiResponse)] enum ContactApiResponse { /// Success #[oai(status = 200)] Ok(Json), /// Bad Request - validation failed #[oai(status = 400)] BadRequest(Json), /// Too Many Requests - rate limit exceeded #[oai(status = 429)] #[allow(dead_code)] TooManyRequests, /// Internal Server Error #[oai(status = 500)] InternalServerError(Json), } /// API for handling contact form submissions and sending emails. #[derive(Clone)] pub struct ContactApi { settings: EmailSettings, } impl From for ContactApi { fn from(settings: EmailSettings) -> Self { Self { settings } } } #[OpenApi(tag = "ApiCategory::Contact")] impl ContactApi { /// Submit a contact form /// /// Send a message through the contact form. Rate limited to prevent spam. #[oai(path = "/contact", method = "post")] async fn submit_contact( &self, body: Json, remote_addr: Option>, ) -> ContactApiResponse { let body = body.0; if body.honeypot.is_some() { tracing::event!( target: "backend::contact", tracing::Level::INFO, "Honeypot triggered, rejecting request silently. IP: {}", remote_addr.map_or_else(|| "No remote address found".to_owned(), |ip| ip.0.to_string()) ); return ContactApiResponse::Ok(ContactResponse::honeypot_response().into()); } if let Err(e) = body.validate() { return ContactApiResponse::BadRequest( >::into(e) .into(), ); } match self.send_emails(&body).await { Ok(()) => { tracing::event!( target: "backend::contact", tracing::Level::INFO, "Message from \"{} <{}>\" sent successfully", body.name, body.email ); ContactApiResponse::Ok(ContactResponse::success().into()) } Err(e) => { tracing::event!(target: "backend::contact", tracing::Level::ERROR, "Failed to send email: {}", e); ContactApiResponse::InternalServerError(e.into()) } } } fn make_email_sender(&self, request: &ContactRequest) -> Result { let email_body = format!( "You submitted the following email:\n\nMessage:\n{}\n\nI’ll try to reply to it as soon as possible. Take care!\n\nBest\n\n***\nThis is an automated email. Please do not reply to it.\n***", request.message ); tracing::event!(target: "backend::contact", tracing::Level::DEBUG, "Sending email content to sender: {}", email_body); let email = Message::builder() .from(self.settings.try_sender_into_mailbox()?) .to(request.try_into()?) .subject("You sent a contact request!".to_string()) .header(ContentType::TEXT_PLAIN) .body(email_body)?; tracing::event!(target: "backend::contact", tracing::Level::DEBUG, "Email to be sent: {}", format!("{email:?}")); Ok(email) } fn make_email_recipient(&self, request: &ContactRequest) -> Result { let email_body = format!( "New contact form submission:\n\nName: {}\nEmail: {}\n\nMessage:\n{}", request.name, request.email, request.message ); tracing::event!(target: "email", tracing::Level::DEBUG, "Sending email content to recipient: {}", email_body); let email = Message::builder() .from(self.settings.try_sender_into_mailbox()?) .reply_to(request.try_into()?) .to(self.settings.try_recpient_into_mailbox()?) .subject(format!("Contact Form: {}", request.name)) .header(ContentType::TEXT_PLAIN) .body(email_body)?; tracing::event!(target: "contact", tracing::Level::DEBUG, "Email to be sent: {}", format!("{email:?}")); Ok(email) } async fn send_emails(&self, request: &ContactRequest) -> Result<(), ContactError> { let mailer = SmtpTransport::try_from(&self.settings)?; let email_to_sender = self.make_email_sender(request)?; let email_to_recipient = self.make_email_recipient(request)?; mailer .send(&email_to_sender) .and_then(|_| mailer.send(&email_to_recipient))?; Ok(()) } /// Internal method for testing - sends emails using a provided transport #[cfg(test)] fn send_emails_with_transport( &self, request: &ContactRequest, transport: &T, ) -> Result<(), ContactError> where T::Error: std::fmt::Debug + std::fmt::Display, { let email_to_sender = self.make_email_sender(request)?; let email_to_recipient = self.make_email_recipient(request)?; transport .send(&email_to_sender) .map_err(|e| ContactError::CouldNotSendEmail(format!("{e:?}")))?; transport .send(&email_to_recipient) .map_err(|e| ContactError::CouldNotSendEmail(format!("{e:?}")))?; Ok(()) } } #[cfg(test)] mod tests { use super::*; use lettre::transport::stub::StubTransport; // Tests for ContactRequest validation #[test] fn contact_request_valid() { let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "This is a test message that is long enough.".to_string(), honeypot: None, }; assert!(request.validate().is_ok()); } #[test] fn contact_request_name_too_short() { let request = ContactRequest { name: String::new(), email: "john@example.com".to_string(), message: "This is a test message that is long enough.".to_string(), honeypot: None, }; assert!(request.validate().is_err()); } #[test] fn contact_request_name_too_long() { let request = ContactRequest { name: "a".repeat(101), email: "john@example.com".to_string(), message: "This is a test message that is long enough.".to_string(), honeypot: None, }; assert!(request.validate().is_err()); } #[test] fn contact_request_name_at_max_length() { let request = ContactRequest { name: "a".repeat(100), email: "john@example.com".to_string(), message: "This is a test message that is long enough.".to_string(), honeypot: None, }; assert!(request.validate().is_ok()); } #[test] fn contact_request_invalid_email() { let request = ContactRequest { name: "John Doe".to_string(), email: "not-an-email".to_string(), message: "This is a test message that is long enough.".to_string(), honeypot: None, }; assert!(request.validate().is_err()); } #[test] fn contact_request_message_too_short() { let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Short".to_string(), honeypot: None, }; assert!(request.validate().is_err()); } #[test] fn contact_request_message_too_long() { let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "a".repeat(5001), honeypot: None, }; assert!(request.validate().is_err()); } #[test] fn contact_request_message_at_min_length() { let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "a".repeat(10), honeypot: None, }; assert!(request.validate().is_ok()); } #[test] fn contact_request_message_at_max_length() { let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "a".repeat(5000), honeypot: None, }; assert!(request.validate().is_ok()); } // Tests for SmtpTransport TryFrom implementation #[test] fn smtp_transport_implicit_tls() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 465, user: "user@example.com".to_string(), password: "password".to_string(), from: "from@example.com".to_string(), recipient: "to@example.com".to_string(), tls: true, starttls: Starttls::Never, }; let result = SmtpTransport::try_from(&settings); assert!(result.is_ok()); } #[test] fn smtp_transport_starttls_always() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), password: "password".to_string(), from: "from@example.com".to_string(), recipient: "to@example.com".to_string(), tls: false, starttls: Starttls::Always, }; let result = SmtpTransport::try_from(&settings); assert!(result.is_ok()); } #[test] fn smtp_transport_starttls_opportunistic() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), password: "password".to_string(), from: "from@example.com".to_string(), recipient: "to@example.com".to_string(), tls: false, starttls: Starttls::Opportunistic, }; let result = SmtpTransport::try_from(&settings); assert!(result.is_ok()); } #[test] fn smtp_transport_no_encryption_with_credentials() { let settings = EmailSettings { host: "localhost".to_string(), port: 1025, user: "user@example.com".to_string(), password: "password".to_string(), from: "from@example.com".to_string(), recipient: "to@example.com".to_string(), tls: false, starttls: Starttls::Never, }; let result = SmtpTransport::try_from(&settings); assert!(result.is_ok()); } #[test] fn smtp_transport_no_encryption_no_credentials() { let settings = EmailSettings { host: "localhost".to_string(), port: 1025, user: String::new(), password: String::new(), from: "from@example.com".to_string(), recipient: "to@example.com".to_string(), tls: false, starttls: Starttls::Never, }; let result = SmtpTransport::try_from(&settings); assert!(result.is_ok()); } // Integration tests for contact API endpoint #[tokio::test] async fn contact_endpoint_honeypot_triggered() { let app = crate::get_test_app(); let cli = poem::test::TestClient::new(app); let body = serde_json::json!({ "name": "Bot Name", "email": "bot@example.com", "message": "This is a spam message from a bot.", "website": "http://spam.com" }); let resp = cli.post("/api/contact").body_json(&body).send().await; resp.assert_status_is_ok(); let json_text = resp.0.into_body().into_string().await.unwrap(); let json: ContactResponse = serde_json::from_str(&json_text).unwrap(); assert!(json.success); assert!(json.message.eq("backend.contact.honeypot")); } #[tokio::test] async fn contact_endpoint_validation_error_empty_name() { let app = crate::get_test_app(); let cli = poem::test::TestClient::new(app); let body = serde_json::json!({ "name": "", "email": "test@example.com", "message": "This is a valid message that is long enough." }); let resp = cli.post("/api/contact").body_json(&body).send().await; resp.assert_status(poem::http::StatusCode::BAD_REQUEST); let json_text = resp.0.into_body().into_string().await.unwrap(); let json: ContactResponse = serde_json::from_str(&json_text).unwrap(); assert!(!json.success); assert!(json.message.eq("backend.contact.errors.validation.name")); } #[tokio::test] async fn contact_endpoint_validation_error_invalid_email() { let app = crate::get_test_app(); let cli = poem::test::TestClient::new(app); let body = serde_json::json!({ "name": "Test User", "email": "not-an-email", "message": "This is a valid message that is long enough." }); let resp = cli.post("/api/contact").body_json(&body).send().await; resp.assert_status(poem::http::StatusCode::BAD_REQUEST); let json_text = resp.0.into_body().into_string().await.unwrap(); let json: ContactResponse = serde_json::from_str(&json_text).unwrap(); assert!(!json.success); assert!(json.message.eq("backend.contact.errors.validation.email")); } #[tokio::test] async fn contact_endpoint_validation_error_message_too_short() { let app = crate::get_test_app(); let cli = poem::test::TestClient::new(app); let body = serde_json::json!({ "name": "Test User", "email": "test@example.com", "message": "Short" }); let resp = cli.post("/api/contact").body_json(&body).send().await; resp.assert_status(poem::http::StatusCode::BAD_REQUEST); let json_text = resp.0.into_body().into_string().await.unwrap(); let json: ContactResponse = serde_json::from_str(&json_text).unwrap(); assert!(!json.success); assert!(json.message.eq("backend.contact.errors.validation.message")); } #[tokio::test] async fn contact_endpoint_validation_error_name_too_long() { let app = crate::get_test_app(); let cli = poem::test::TestClient::new(app); let body = serde_json::json!({ "name": "a".repeat(101), "email": "test@example.com", "message": "This is a valid message that is long enough." }); let resp = cli.post("/api/contact").body_json(&body).send().await; resp.assert_status(poem::http::StatusCode::BAD_REQUEST); let json_text = resp.0.into_body().into_string().await.unwrap(); let json: ContactResponse = serde_json::from_str(&json_text).unwrap(); assert!(!json.success); assert!(json.message.eq("backend.contact.errors.validation.name")); } #[tokio::test] async fn contact_endpoint_validation_error_message_too_long() { let app = crate::get_test_app(); let cli = poem::test::TestClient::new(app); let body = serde_json::json!({ "name": "Test User", "email": "test@example.com", "message": "a".repeat(5001) }); let resp = cli.post("/api/contact").body_json(&body).send().await; resp.assert_status(poem::http::StatusCode::BAD_REQUEST); let json_text = resp.0.into_body().into_string().await.unwrap(); let json: ContactResponse = serde_json::from_str(&json_text).unwrap(); assert!(!json.success); assert!(json.message.eq("backend.contact.errors.validation.message")); } // Tests for ContactRequest TryFrom to Mailbox #[test] fn contact_request_to_mailbox_success() { let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "This is a test message.".to_string(), honeypot: None, }; let result: Result = (&request).try_into(); assert!(result.is_ok()); let mailbox = result.unwrap(); assert_eq!(mailbox.name, Some("John Doe".to_string())); assert_eq!(mailbox.email.to_string(), "john@example.com"); } #[test] fn contact_request_to_mailbox_invalid_email() { let request = ContactRequest { name: "John Doe".to_string(), email: "not-an-email".to_string(), message: "This is a test message.".to_string(), honeypot: None, }; let result: Result = (&request).try_into(); assert!(result.is_err()); match result.unwrap_err() { ContactError::CouldNotParseRequestEmailAddress(email) => { assert_eq!(email, "not-an-email"); } _ => panic!("Expected CouldNotParseRequestEmailAddress error"), } } // Tests for ContactResponse factory methods #[test] fn contact_response_success_creates_correct_response() { let response = ContactResponse::success(); assert!(response.success); assert_eq!(response.message, "backend.contact.success"); } #[test] fn contact_response_honeypot_creates_correct_response() { let response = ContactResponse::honeypot_response(); assert!(response.success); assert_eq!(response.message, "backend.contact.honeypot"); } // Tests for ContactResponse to Json conversion #[test] fn contact_response_to_json() { let response = ContactResponse::success(); let json: Json = response.into(); assert!(json.0.success); assert_eq!(json.0.message, "backend.contact.success"); } // Tests for email building methods #[test] fn make_email_sender_builds_correct_message() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message content".to_string(), honeypot: None, }; let result = api.make_email_sender(&request); assert!(result.is_ok()); let message = result.unwrap(); let message_str = format!("{message:?}"); // Check that the message contains key elements assert!(message_str.contains("john@example.com")); assert!(message_str.contains("John Doe")); assert!(message_str.contains("noreply@example.com")); } #[test] fn make_email_sender_fails_with_invalid_from_address() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "invalid-email".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message".to_string(), honeypot: None, }; let result = api.make_email_sender(&request); assert!(result.is_err()); } #[test] fn make_email_sender_fails_with_invalid_request_email() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "invalid-email".to_string(), message: "Test message".to_string(), honeypot: None, }; let result = api.make_email_sender(&request); assert!(result.is_err()); match result.unwrap_err() { ContactError::CouldNotParseRequestEmailAddress(_) => (), _ => panic!("Expected CouldNotParseRequestEmailAddress error"), } } #[test] fn make_email_recipient_builds_correct_message() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message content".to_string(), honeypot: None, }; let result = api.make_email_recipient(&request); assert!(result.is_ok()); let message = result.unwrap(); let message_str = format!("{message:?}"); // Check that the message contains key elements assert!(message_str.contains("admin@example.com")); assert!(message_str.contains("john@example.com")); // Reply-to assert!(message_str.contains("noreply@example.com")); assert!(message_str.contains("Contact Form: John Doe")); } #[test] fn make_email_recipient_fails_with_invalid_recipient() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "invalid-email".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message".to_string(), honeypot: None, }; let result = api.make_email_recipient(&request); assert!(result.is_err()); } #[test] fn make_email_recipient_fails_with_invalid_from_address() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "invalid-email".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message".to_string(), honeypot: None, }; let result = api.make_email_recipient(&request); assert!(result.is_err()); } #[test] fn make_email_recipient_includes_message_content() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "Jane Smith".to_string(), email: "jane@example.com".to_string(), message: "This is a unique test message with specific content".to_string(), honeypot: None, }; let result = api.make_email_recipient(&request); assert!(result.is_ok()); } #[test] fn contact_api_from_email_settings() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Always, tls: false, }; let api = ContactApi::from(settings.clone()); assert_eq!(api.settings.host, settings.host); assert_eq!(api.settings.port, settings.port); assert_eq!(api.settings.from, settings.from); } // Tests for send_emails with mock transport #[test] fn send_emails_with_stub_transport_success() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message content".to_string(), honeypot: None, }; let transport = StubTransport::new_ok(); let result = api.send_emails_with_transport(&request, &transport); assert!(result.is_ok()); } #[test] fn send_emails_with_stub_transport_sends_two_emails() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "Jane Smith".to_string(), email: "jane@example.com".to_string(), message: "Another test message".to_string(), honeypot: None, }; let transport = StubTransport::new_ok(); api.send_emails_with_transport(&request, &transport) .unwrap(); // StubTransport doesn't provide a way to count messages, but we verified it succeeded // If either email failed to build or send, the test would fail } #[test] fn send_emails_with_stub_transport_fails_with_invalid_from() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "invalid-email".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message".to_string(), honeypot: None, }; let transport = StubTransport::new_ok(); let result = api.send_emails_with_transport(&request, &transport); assert!(result.is_err()); match result.unwrap_err() { ContactError::CouldNotParseSettingsEmail(_) => (), e => panic!("Expected CouldNotParseSettingsEmail, got {:?}", e), } } #[test] fn send_emails_with_stub_transport_fails_with_invalid_request_email() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "not-an-email".to_string(), message: "Test message".to_string(), honeypot: None, }; let transport = StubTransport::new_ok(); let result = api.send_emails_with_transport(&request, &transport); assert!(result.is_err()); match result.unwrap_err() { ContactError::CouldNotParseRequestEmailAddress(_) => (), e => panic!("Expected CouldNotParseRequestEmailAddress, got {:?}", e), } } #[test] fn send_emails_with_failing_transport() { let settings = EmailSettings { host: "smtp.example.com".to_string(), port: 587, user: "user@example.com".to_string(), from: "noreply@example.com".to_string(), password: "password".to_string(), recipient: "admin@example.com".to_string(), starttls: Starttls::Never, tls: false, }; let api = ContactApi::from(settings); let request = ContactRequest { name: "John Doe".to_string(), email: "john@example.com".to_string(), message: "Test message".to_string(), honeypot: None, }; // Create a transport that always fails let transport = StubTransport::new_error(); let result = api.send_emails_with_transport(&request, &transport); assert!(result.is_err()); match result.unwrap_err() { ContactError::CouldNotSendEmail(_) => (), e => panic!("Expected CouldNotSendEmail, got {:?}", e), } } }