Do not allocate.

Unhappy path tests.

src/email_client.rs

@@ -27,11 +27,11 @@ impl EmailClient {
     ) -> Result<(), reqwest::Error> {
         let url = format!("{}/email", self.base_url);
         let request_body = SendEmailRequest {
-            from: self.sender.as_ref().to_owned(),
-            to: recipient.as_ref().to_owned(),
-            subject: subject.into(),
-            html_body: html_content.into(),
-            text_body: text_content.into(),
+            from: self.sender.as_ref(),
+            to: recipient.as_ref(),
+            subject,
+            html_body: html_content,
+            text_body: text_content,
         };
         self.http_client
             .post(&url)
@@ -45,22 +45,23 @@ impl EmailClient {
 
 #[derive(serde::Serialize)]
 #[serde(rename_all = "PascalCase")]
-struct SendEmailRequest {
-    from: String,
-    to: String,
-    subject: String,
-    html_body: String,
-    text_body: String,
+struct SendEmailRequest<'a> {
+    from: &'a str,
+    to: &'a str,
+    subject: &'a str,
+    html_body: &'a str,
+    text_body: &'a str,
 }
 
 #[cfg(test)]
 mod tests {
     use crate::domain::SubscriberEmail;
     use crate::email_client::EmailClient;
+    use claim::{assert_err, assert_ok};
     use fake::faker::internet::en::SafeEmail;
     use fake::faker::lorem::en::{Paragraph, Sentence};
     use fake::{Fake, Faker};
-    use wiremock::matchers::{header, header_exists, method, path};
+    use wiremock::matchers::{any, header, header_exists, method, path};
     use wiremock::{Mock, MockServer, Request, ResponseTemplate};
 
     struct SendEmailBodyMatcher;
@@ -81,7 +82,7 @@ mod tests {
     }
 
     #[actix_rt::test]
-    async fn send_email_fires_a_request_to_base_url() {
+    async fn send_email_sends_the_expected_request() {
         // Arrange
         let mock_server = MockServer::start().await;
         let sender = SubscriberEmail::parse(SafeEmail().fake()).unwrap();
@@ -108,4 +109,57 @@ mod tests {
 
         // Assert
     }
+
+    #[actix_rt::test]
+    async fn send_email_succeeds_if_the_server_returns_200() {
+        // Arrange
+        let mock_server = MockServer::start().await;
+        let sender = SubscriberEmail::parse(SafeEmail().fake()).unwrap();
+        let email_client = EmailClient::new(mock_server.uri(), sender, Faker.fake());
+
+        let subscriber_email = SubscriberEmail::parse(SafeEmail().fake()).unwrap();
+        let subject: String = Sentence(1..2).fake();
+        let content: String = Paragraph(1..10).fake();
+
+        Mock::given(any())
+            .respond_with(ResponseTemplate::new(200))
+            .expect(1)
+            .mount(&mock_server)
+            .await;
+
+        // Act
+        let outcome = email_client
+            .send_email(subscriber_email, &subject, &content, &content)
+            .await;
+
+        // Assert
+        assert_ok!(outcome);
+    }
+
+    #[actix_rt::test]
+    async fn send_email_fails_if_the_server_returns_500() {
+        // Arrange
+        let mock_server = MockServer::start().await;
+        let sender = SubscriberEmail::parse(SafeEmail().fake()).unwrap();
+        let email_client = EmailClient::new(mock_server.uri(), sender, Faker.fake());
+
+        let subscriber_email = SubscriberEmail::parse(SafeEmail().fake()).unwrap();
+        let subject: String = Sentence(1..2).fake();
+        let content: String = Paragraph(1..10).fake();
+
+        Mock::given(any())
+            // Not a 200 anymore!
+            .respond_with(ResponseTemplate::new(500))
+            .expect(1)
+            .mount(&mock_server)
+            .await;
+
+        // Act
+        let outcome = email_client
+            .send_email(subscriber_email, &subject, &content, &content)
+            .await;
+
+        // Assert
+        assert_err!(outcome);
+    }
 }