Add an integration test for sign in

backend/tests/http.rs

@@ -137,3 +137,39 @@ async fn sign_up() -> Result<(), Box<dyn Error>> {
 
     Ok(())
 }
+
+#[derive(Serialize, Debug)]
+pub struct SignInFormData {
+    email: String,
+    password: String,
+}
+
+#[tokio::test]
+async fn sign_in() -> Result<(), Box<dyn Error>> {
+    // Arrange.
+    let state = utils::common_state().await?;
+    let _user_id = utils::create_user(
+        &state.db_connection,
+        "president@spaceball.planet",
+        "12345678",
+    )
+    .await?;
+    let server = TestServer::new(app::make_service(state))?;
+
+    // Act.
+    let response = server
+        .post("/signin")
+        .form(&SignInFormData {
+            email: "president@spaceball.planet".into(),
+            password: "12345678".into(),
+        })
+        .await;
+
+    // Assert.
+    response.assert_status_see_other(); // Redirection after successful sign in.
+    response.assert_text("");
+    response.assert_header("location", "/en/"); // English is the default language.
+    dbg!(&response);
+
+    Ok(())
+}