Email client, application startup logic and tests

tests/api/subscriptions.rs

@@ -0,0 +1,61 @@
+use crate::helpers::TestApp;
+
+#[tokio::test]
+async fn subscribe_returns_a_200_for_valid_form_data() {
+    let app = TestApp::spawn().await;
+
+    let body = "name=alphonse&email=alphonse.paix%40outlook.com";
+    let response = app.post_subscriptions(body.into()).await;
+
+    assert_eq!(200, response.status().as_u16());
+
+    let saved = sqlx::query!("SELECT email, name FROM subscriptions")
+        .fetch_one(&app.connection_pool)
+        .await
+        .expect("Failed to fetch saved subscription");
+
+    assert_eq!(saved.email, "alphonse.paix@outlook.com");
+    assert_eq!(saved.name, "alphonse");
+}
+
+#[tokio::test]
+async fn subscribe_returns_a_422_when_data_is_missing() {
+    let app = TestApp::spawn().await;
+
+    let test_cases = [
+        ("name=Alphonse", "missing the email"),
+        ("email=alphonse.paix%40outlook.com", "missing the name"),
+        ("", "missing both name and email"),
+    ];
+    for (invalid_body, error_message) in test_cases {
+        let response = app.post_subscriptions(invalid_body.into()).await;
+
+        assert_eq!(
+            422,
+            response.status().as_u16(),
+            "the API did not fail with 422 Unprocessable Entity when the payload was {}.",
+            error_message
+        );
+    }
+}
+
+#[tokio::test]
+async fn subscribe_returns_a_400_when_fields_are_present_but_invalid() {
+    let app = TestApp::spawn().await;
+
+    let test_cases = [
+        ("name=&email=alphonse.paix%40outlook.com", "empty name"),
+        ("name=Alphonse&email=", "empty email"),
+        ("name=Alphonse&email=not-an-email", "invalid email"),
+    ];
+    for (body, description) in test_cases {
+        let response = app.post_subscriptions(body.into()).await;
+
+        assert_eq!(
+            400,
+            response.status().as_u16(),
+            "the API did not return a 400 Bad Request when the payload had an {}.",
+            description
+        );
+    }
+}