构建一个rust生产应用读书笔记7-确认邮件2

编码浪子2024-12-26 10:24

共享测试辅助

当每个集成测试文件都是一个独立的可执行文件时，共享测试辅助函数的一种常见方法是创建一个单独的模块，该模块可以被所有测试文件导入和使用。这个模块通常包含所有测试需要共用的辅助函数、常量、配置和其他资源。如果遵循这种做法，你可以按照以下步骤操作：

在你的 tests 目录下，创建一个名为 helpers 的模块

rust 复制代码 
//! tests/health_check.rs
// [...]
mod helpers;
// [...]

在 Rust 项目中，如果你将 helpers 模块作为子模块捆绑到像 health_check 这样的测试可执行文件中，那么你可以在你的测试用例中访问它暴露的函数。这种方法一开始工作得很好，但它会导致"函数从未被使用"的警告，因为 helpers 是作为一个子模块捆绑的，而不是作为第三方 crate 调用的。Cargo 会独立编译每个测试可执行文件，并且如果对于特定的测试文件，helpers 中的一个或多个公共函数从未被调用，就会发出警告。随着你的测试套件的逐渐增长，这种情况几乎是不可避免的------并不是所有的测试文件都会使用所有的辅助方法。

为了避免这些未使用的函数警告，你可以采用第二种方法，充分利用每个 tests 目录下的文件都是一个独立的可执行文件这一特性：为每个测试创建作用域限定的子模块。具体来说，你可以为不同的测试创建特定的辅助模块，这样只有当测试确实需要时才会包含这些辅助函数，从而避免了全局辅助模块带来的未使用函数警告问题。

让我们创建一个 api 文件夹放在 tests 下，并在里面放置一个 main.rs 文件：

  1. 创建 tests/api 目录。
  2. 在 tests/api 目录下创建 main.rs 文件。这个文件将作为 api 测试的入口点。
  3. 如果有与 api 测试相关的辅助函数，你可以在 tests/api 下创建一个 helpers.rs 或者 mod.rs 文件来存放这些辅助函数。
  4. 确保你在 main.rs 中正确引用了这些辅助函数，例如通过 mod helpers; 来声明 helpers 模块（假设你创建的是 mod.rs）或者直接通过 use api::helpers; 引用它们（如果你创建的是 helpers.rs 并且已经在 main.rs 中声明了 mod helpers;）。
  5. 对于其他不同类型的测试（如 db_tests, service_tests 等），你可以重复上述步骤，为每种类型的测试创建各自的目录和辅助模块。

修改后的目录结构如下：

rust 复制代码 
tests
└── api
    ├── health_check.rs
    ├── helpers.rs
    ├── main.rs
    └── subscriptions.rs

在main.rs添加子模块

rust 复制代码 
mod health_check;
mod helpers;
mod subscriptions;

health_check.rs 到helpers.rs

rust 复制代码 
// Ensure that the `tracing` stack is only initialised once using `once_cell`
use secrecy::Secret;
use sqlx::{Connection, Executor, PgConnection, PgPool};
use std::net::TcpListener;
use std::sync::LazyLock;
use uuid::Uuid;
use zero2prod::configuration::{get_configuration, DatabaseSettings};
use zero2prod::email_client::EmailClient;
use zero2prod::startup::run;
use zero2prod::telemetry::{get_subscriber, init_subscriber};

static TRACING: LazyLock<()> = LazyLock::new(|| {
    let default_filter_level = "info".to_string();
    let subscriber_name = "test".to_string();
    if std::env::var("TEST_LOG").is_ok() {
        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::stdout);
        init_subscriber(subscriber);
    } else {
        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::sink);
        init_subscriber(subscriber);
    };
});

pub struct TestApp {
    pub address: String,
    pub db_pool: PgPool,
}

pub async fn spawn_app() -> TestApp {
    // The first time `initialize` is invoked the code in `TRACING` is executed.
    // All other invocations will instead skip execution.
    LazyLock::force(&TRACING);

    let listener = TcpListener::bind("127.0.0.1:0").expect("Failed to bind random port");
    // We retrieve the port assigned to us by the OS
    let port = listener.local_addr().unwrap().port();
    let address = format!("http://127.0.0.1:{}", port);

    let mut configuration = get_configuration().expect("Failed to read configuration.");
    configuration.database.database_name = Uuid::new_v4().to_string();
    let connection_pool = configure_database(&configuration.database).await;

    let sender_email = configuration
        .email_client
        .sender()
        .expect("Invalid sender email address.");
    let timeout = configuration.email_client.timeout();
    let email_client = EmailClient::new(
        configuration.email_client.base_url,
        sender_email,
        configuration.email_client.authorization_token,
        timeout,
    );

    let server =
        run(listener, connection_pool.clone(), email_client).expect("Failed to bind address");
    let _ = tokio::spawn(server);
    TestApp {
        address,
        db_pool: connection_pool,
    }
}

pub async fn configure_database(config: &DatabaseSettings) -> PgPool {
    // Create database
    let maintenance_settings = DatabaseSettings {
        database_name: "postgres".to_string(),
        username: "postgres".to_string(),
        password: Secret::new("password".to_string()),
        ..config.clone()
    };
    let mut connection = PgConnection::connect_with(&maintenance_settings.connect_options())
        .await
        .expect("Failed to connect to Postgres");
    connection
        .execute(format!(r#"CREATE DATABASE "{}";"#, config.database_name).as_str())
        .await
        .expect("Failed to create database.");

    // Migrate database
    let connection_pool = PgPool::connect_with(config.connect_options())
        .await
        .expect("Failed to connect to Postgres.");
    sqlx::migrate!("./migrations")
        .run(&connection_pool)
        .await
        .expect("Failed to migrate the database");
    connection_pool
}

注意：spawn_app() 函数需要改成pub，可以让其他类访问

subscriptions.rs

rust 复制代码 
use crate::helpers::spawn_app;

#[tokio::test]
async fn subscribe_returns_a_200_for_valid_form_data() {
    // Arrange
    let app = spawn_app().await;
    let client = reqwest::Client::new();
    let body = "name=le%20guin&email=ursula_le_guin%40gmail.com";

    // Act
    let response = client
        .post(&format!("{}/subscriptions", &app.address))
        .header("Content-Type", "application/x-www-form-urlencoded")
        .body(body)
        .send()
        .await
        .expect("Failed to execute request.");

    // Assert
    assert_eq!(200, response.status().as_u16());

    let saved = sqlx::query!("SELECT email, name FROM subscriptions",)
        .fetch_one(&app.db_pool)
        .await
        .expect("Failed to fetch saved subscription.");

    assert_eq!(saved.email, "ursula_le_guin@gmail.com");
    assert_eq!(saved.name, "le guin");
}

#[tokio::test]
async fn subscribe_returns_a_400_when_data_is_missing() {
    // Arrange
    let app = spawn_app().await;
    let client = reqwest::Client::new();
    let test_cases = vec![
        ("name=le%20guin", "missing the email"),
        ("email=ursula_le_guin%40gmail.com", "missing the name"),
        ("", "missing both name and email"),
    ];

    for (invalid_body, error_message) in test_cases {
        // Act
        let response = client
            .post(&format!("{}/subscriptions", &app.address))
            .header("Content-Type", "application/x-www-form-urlencoded")
            .body(invalid_body)
            .send()
            .await
            .expect("Failed to execute request.");

        // Assert
        assert_eq!(
            400,
            response.status().as_u16(),
            // Additional customised error message on test failure
            "The API did not fail with 400 Bad Request when the payload was {}.",
            error_message
        );
    }
}

#[tokio::test]
async fn subscribe_returns_a_400_when_fields_are_present_but_invalid() {
    // Arrange
    let app = spawn_app().await;
    let client = reqwest::Client::new();
    let test_cases = vec![
        ("name=&email=ursula_le_guin%40gmail.com", "empty name"),
        ("name=Ursula&email=", "empty email"),
        ("name=Ursula&email=definitely-not-an-email", "invalid email"),
    ];

    for (body, description) in test_cases {
        // Act
        let response = client
            .post(&format!("{}/subscriptions", &app.address))
            .header("Content-Type", "application/x-www-form-urlencoded")
            .body(body)
            .send()
            .await
            .expect("Failed to execute request.");

        // Assert
        assert_eq!(
            400,
            response.status().as_u16(),
            "The API did not return a 400 Bad Request when the payload was {}.",
            description
        );
    }
}

恭喜，你已经将测试套件分解为更小、更易管理的模块！这种新的结构带来了几个积极的副作用：

  1. 递归性 ：如果 tests/api/subscriptions.rs 文件变得难以管理，你可以将其转换为一个模块。这样，tests/api/subscriptions/helpers.rs 可以保存订阅特定的测试辅助函数，并且可以有多个专注于特定流程或问题的测试文件。这使得即使当某个部分变得复杂时，你仍然能够保持良好的组织结构。

  2. 封装 ：你的测试只需要知道关于 spawn_app 和 TestApp 的信息------没有必要暴露 configure_database 或 TRACING 这样的细节。通过将这些复杂性隐藏在 helpers 模块中，你可以使测试代码更加简洁和易于理解。

  3. 单个测试二进制文件 ：如果你有一个大型测试套件并且使用的是扁平文件结构，那么每次运行 cargo test 时，你可能会构建数十个可执行文件。虽然每个可执行文件是并行编译的，但链接阶段却是完全顺序进行的！将所有测试用例捆绑到一个可执行文件中可以减少在持续集成（CI）环境中编译测试套件所花费的时间。

修改启动业务

从代码结构的角度来看，启动逻辑可以被设计为一个函数，该函数接收 Settings 作为输入，并返回应用程序实例作为输出。因此， main 函数应该尽量简洁，主要负责调用这个启动逻辑函数并处理任何高层级的错误。

rust 复制代码 
//!main.rs
use zero2prod::{
    configuration::get_configuration,
    telemetry::{get_subscriber, init_subscriber},
};

#[tokio::main]
async fn main() -> std::io::Result<()> {
    let subscriber = get_subscriber("zero2prod".into(), "info".into(), std::io::stdout);
    init_subscriber(subscriber);

    let configuration = get_configuration().expect("Failed to read configuration.");
    let application = Application::build(configuration).await?;
    application.run_util_stoped().await?;
    Ok(())
}

startup.rs重构

rust 复制代码 
//startup.rs
use crate::configuration::{DatabaseSettings, Settings};
use crate::email_client::EmailClient;
use crate::routes::{health_check, subscribe};
use actix_web::dev::Server;
use actix_web::web::Data;
use actix_web::{web, App, HttpServer};
use sqlx::postgres::PgPoolOptions;
use sqlx::PgPool;
use std::net::TcpListener;
use tracing_actix_web::TracingLogger;

pub struct Application {
    port: u16,
    server: Server,
}

impl Application {
    pub async fn build(configuration: Settings) -> Result<Self, std::io::Error> {
        let connection_pool = get_connection_pool(&configuration.database);
        let sender_email = configuration
            .email_client
            .sender()
            .expect("Invalid sender email address.");
        let timeout = configuration.email_client.timeout();
        let email_client = EmailClient::new(
            configuration.email_client.base_url,
            sender_email,
            configuration.email_client.authorization_token,
            timeout,
        );
        let address = format!(
            "{}:{}",
            configuration.application.host, configuration.application.port
        );
        let listener = TcpListener::bind(address)?;
        let port = listener.local_addr().unwrap().port();
        let server = run(listener, connection_pool, email_client)?;
        Ok(Self { port, server })
    }

    pub fn port(&self) -> u16 {
        self.port
    }

    pub async fn run_util_stoped(self) -> Result<(), std::io::Error> {
        self.server.await
    }
}

pub fn get_connection_pool(configuration: &DatabaseSettings) -> PgPool {
    PgPoolOptions::new().connect_lazy_with(configuration.connect_options())
}

pub fn run(
    listener: TcpListener,
    db_pool: PgPool,
    email_client: EmailClient,
) -> Result<Server, std::io::Error> {
    let db_pool = Data::new(db_pool);
    let email_client = Data::new(email_client);
    let server = HttpServer::new(move || {
        App::new()
            .wrap(TracingLogger::default())
            .route("/health_check", web::get().to(health_check))
            .route("/subscriptions", web::post().to(subscribe))
            .app_data(db_pool.clone())
            .app_data(email_client.clone())
    })
    .listen(listener)?
    .run();
    Ok(server)
}

helpers重构

rust 复制代码 
pub async fn spawn_app() -> TestApp {
    LazyLock::force(&TRACING);

    let configuration = {
        let mut c = get_configuration().expect("Failed to read configuration.");
        c.database.database_name = Uuid::new_v4().to_string();
        c.application.port = 0;
        c
    };

    configure_database(&configuration.database).await;

    let application = Application::build(configuration.clone())
        .await
        .expect("Failed to build application.");
    let address = format!("http://localhost:{}", application.port());
    let _ = tokio::spawn(application.run_util_stoped());

    TestApp {
        address,
        db_pool: get_connection_pool(&configuration.database),
    }
}

构建API Client

helpers.rs

rust 复制代码 
//[..]
impl TestApp {
    pub async fn post_subscriptions(&self, body: String) -> reqwest::Response {
        reqwest::Client::new()
            .post(&format!("{}/subscriptions", &self.address))
            .header("Content-Type", "application/x-www-form-urlencoded")
            .body(body)
            .send()
            .await
            .expect("Failed to execute reuest.")
    }
}

//[..]

subscriptions.rs

rust 复制代码 
use crate::helpers::spawn_app;

#[tokio::test]
async fn subscribe_returns_a_200_for_valid_form_data() {
    // Arrange
    let app = spawn_app().await;
    let body = "name=le%20guin&email=ursula_le_guin%40gmail.com";

    // Act
    let response = app.post_subscriptions(body.into()).await;

    // Assert
    assert_eq!(200, response.status().as_u16());

    let saved = sqlx::query!("SELECT email, name FROM subscriptions",)
        .fetch_one(&app.db_pool)
        .await
        .expect("Failed to fetch saved subscription.");

    assert_eq!(saved.email, "ursula_le_guin@gmail.com");
    assert_eq!(saved.name, "le guin");
}

#[tokio::test]
async fn subscribe_returns_a_400_when_data_is_missing() {
    // Arrange
    let app = spawn_app().await;
    let client = reqwest::Client::new();
    let test_cases = vec![
        ("name=le%20guin", "missing the email"),
        ("email=ursula_le_guin%40gmail.com", "missing the name"),
        ("", "missing both name and email"),
    ];

    for (invalid_body, error_message) in test_cases {
        // Act
        let response = app.post_subscriptions(invalid_body.into()).await;

        // Assert
        assert_eq!(
            400,
            response.status().as_u16(),
            // Additional customised error message on test failure
            "The API did not fail with 400 Bad Request when the payload was {}.",
            error_message
        );
    }
}

#[tokio::test]
async fn subscribe_returns_a_400_when_fields_are_present_but_invalid() {
    // Arrange
    let app = spawn_app().await;
    let test_cases = vec![
        ("name=&email=ursula_le_guin%40gmail.com", "empty name"),
        ("name=Ursula&email=", "empty email"),
        ("name=Ursula&email=definitely-not-an-email", "invalid email"),
    ];

    for (body, description) in test_cases {
        // Act
        let response = app.post_subscriptions(body.into()).await;
        // Assert
        assert_eq!(
            400,
            response.status().as_u16(),
            "The API did not return a 400 Bad Request when the payload was {}.",
            description
        );
    }
}

目前为止，我们完成了第二阶段的重构，代码结构看起来视乎更清晰，接下来继续.....

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