我尝试在Actix Web应用程序的CI工作流中运行cargo test。每个测试都通过首先连接到默认数据库（“postgres”）然后执行SQL查询来创建自己的数据库。
这是当前使用的工作流，“测试postgres连接”成功运行，但“Cargo测试”失败：

on: [push, pull_request]

name: CI

env:
  CARGO_TERM_COLOR: always

jobs:
  test:
    name: Test
    runs-on: ubuntu-latest
    container: rust:latest
    services:
      postgres:
        image: postgres:latest
        env:
          POSTGRES_PASSWORD: postgres
        ports:
          - 5432:5432
        # Set health checks to wait until postgres has started
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
    steps:
      - name: Checkout sources
        uses: actions/checkout@v2

      - name: Install stable toolchain
        uses: actions-rs/toolchain@v1
        with:
          profile: minimal
          toolchain: stable
          override: true

      - name: Install PSQL
        run: |
          apt update
          apt install -y postgresql-client

      - name: Test postgres connection
        run: psql -h postgres -d postgres -U postgres -c 'SELECT 1;'
        env:
          PGPASSWORD: postgres

      - name: Cargo test
        uses: actions-rs/cargo@v1
        with:
          command: test
          args: --verbose
        env:
          POSTGRES_USER: postgres
          POSTGRES_PASSWORD: postgres

下面是其中一个测试的示例：

struct Context {
    pub psql_user: String,
    pub psql_pw: String,
}

impl Context {
    fn new() -> Self {
        dotenv().ok();
        let psql_user =
            env::var("POSTGRES_USER").expect("POSTGRES_USER must be set for integration tests");
        let psql_pw = env::var("POSTGRES_PASSWORD")
            .expect("POSTGRES_PASSWORD must be set for integration tests");
        let database_url = format!(
            "postgres://{}:{}@localhost:5432/postgres",
            psql_user, psql_pw
        );
        let mut conn = PgConnection::establish(&database_url)
            .expect("Failed to connect to the database 'postgres'"); // This panics

        // ...
    }
}

# [actix_web::test]

async fn test_create_task_req() {
    let ctx = Context::new("create_task_test");

    // ...
}

我假设错误是在我的代码中的某个地方，因为工作流中的一切都运行良好，直到cargo test抛出以下错误：

---- test_create_task_req stdout ----
thread 'test_create_task_req' panicked at 'Failed to connect to the database 'postgres': 
BadConnection("could not connect to server: Connection refused
    Is the server running on host \"localhost\" (127.0.0.1) and accepting
    TCP/IP connections on port 5432?
could not connect to server: Cannot assign requested address
    Is the server running on host \"localhost\" (::1) and accepting
    TCP/IP connections on port 5432?
")', 
tests/tasks_crud_integration.rs:42:14

在本地运行cargo test时，不会出现任何问题。