Allow multiple integration tests at the main app level

[josecelano]

Goal

Enable multiple independent main-application integration tests to run in parallel without port conflicts, configuration collisions, or logging initialization errors.

Current plan update

After #2036, #2041, and #2039 land, add a shared-event-bus policy integration test:

• Start enabled and metrics-disabled HTTP/UDP listeners.
• Verify they share aggregate event streams/repositories as designed.
• Verify only enabled listener traffic changes public metrics.
• Verify the test uses canonical registry discovery rather than bind-IP classification or fixed startup delays.

Existing scope

• Isolate temporary config/storage per test.
• Use port zero and discover final endpoints.
• Remove shared environment-variable test collisions.
• Run cargo test --test stats concurrently.

Related to #2035, #2036, #2039, and #2041.

[josecelano]

Hi @da2ce7 I can't reproduce problem 1 anymore, so I have removed it from the list for now.

I tried to reproduce it by replacing the whole integration test filetests/servers/api/contract/stats/mod.rs with:

use std::env;

use torrust_tracker_lib::app;

#[tokio::test]
async fn the_stats_api_endpoint_should_return_the_global_stats_1() {
    let config_with_two_http_trackers = r#"
        [metadata]
        app = "torrust-tracker"
        purpose = "configuration"
        schema_version = "2.0.0"

        [logging]
        threshold = "info"

        [core]
        listed = false
        private = false

        [core.database]
        driver = "sqlite3"
        path = "./integration_tests_sqlite3.db"

        [health_check_api]
        bind_address = "0.0.0.0:0"        
        "#;

    env::set_var("TORRUST_TRACKER_CONFIG_TOML", config_with_two_http_trackers);

    let (_app_container, _jobs, _registar) = app::run().await;
}

#[tokio::test]
async fn the_stats_api_endpoint_should_return_the_global_stats_2() {
    let config_with_two_http_trackers = r#"
        [metadata]
        app = "torrust-tracker"
        purpose = "configuration"
        schema_version = "2.0.0"

        [logging]
        threshold = "info"

        [core]
        listed = false
        private = false

        [core.database]
        driver = "sqlite3"
        path = "./integration_tests_sqlite3.db"

        [health_check_api]
        bind_address = "0.0.0.0:0"        
        "#;

    env::set_var("TORRUST_TRACKER_CONFIG_TOML", config_with_two_http_trackers);

    let (_app_container, _jobs, _registar) = app::run().await;
}

• By using port 0 we don't have problem 2.
• By using the same config env var value, you don't have problem 3

The output is fine:

$ cargo test -- --nocapture 
   Compiling torrust-tracker v3.0.0-develop (/home/josecelano/Documents/git/committer/me/github/torrust/torrust-tracker)
    Finished `test` profile [optimized + debuginfo] target(s) in 41.40s
     Running unittests src/lib.rs (target/debug/deps/torrust_tracker_lib-b7b2d1fc55bfe6d2)

running 8 tests
Loading extra configuration from default configuration file: `./share/default/config/tracker.development.sqlite3.toml` ...
test console::ci::e2e::logs_parser::tests::it_should_replace_wildcard_ip_with_localhost ... ok
test bootstrap::config::tests::it_should_load_with_default_config ... ok
test console::ci::e2e::logs_parser::tests::it_should_ignore_logs_with_no_matching_lines ... ok
test console::ci::e2e::logs_parser::tests::it_should_parse_from_logs_with_valid_logs ... ok
test console::ci::e2e::logs_parser::tests::it_should_parse_multiple_services ... ok
test console::ci::e2e::logs_parser::tests::it_should_support_colored_output ... ok
test bootstrap::jobs::http_tracker::tests::it_should_start_http_tracker ... ok
test bootstrap::jobs::tracker_apis::tests::it_should_start_http_tracker ... ok

test result: ok. 8 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

     Running unittests src/bin/e2e_tests_runner.rs (target/debug/deps/e2e_tests_runner-f6f80a69d5eb03c8)

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

     Running unittests src/bin/http_health_check.rs (target/debug/deps/http_health_check-f1a2a0212e5183ec)

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

     Running unittests src/bin/profiling.rs (target/debug/deps/profiling-8fb61b87807ca189)

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

     Running unittests src/main.rs (target/debug/deps/torrust_tracker-91a953124cd232d6)

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

     Running tests/integration.rs (target/debug/deps/integration-015c9121a9272ff8)

running 2 tests
Loading extra configuration from environment variable:
 
        [metadata]
        app = "torrust-tracker"
        purpose = "configuration"
        schema_version = "2.0.0"

        [logging]
        threshold = "info"

        [core]
        listed = false
        private = false

        [core.database]
        driver = "sqlite3"
        path = "./integration_tests_sqlite3.db"

        [health_check_api]
        bind_address = "0.0.0.0:0"        
        
Loading extra configuration from default configuration file: `./share/default/config/tracker.development.sqlite3.toml` ...
Loading extra configuration from environment variable:
 
        [metadata]
        app = "torrust-tracker"
        purpose = "configuration"
        schema_version = "2.0.0"

        [logging]
        threshold = "info"

        [core]
        listed = false
        private = false

        [core.database]
        driver = "sqlite3"
        path = "./integration_tests_sqlite3.db"

        [health_check_api]
        bind_address = "0.0.0.0:0"        
        
Loading extra configuration from default configuration file: `./share/default/config/tracker.development.sqlite3.toml` ...
2025-04-04T09:56:36.115216Z  INFO torrust_tracker_configuration::logging: Logging initialized
2025-04-04T09:56:36.115232Z  INFO torrust_tracker_lib::bootstrap::app: Configuration:
{
  "metadata": {
    "app": "torrust-tracker",
    "purpose": "configuration",
    "schema_version": "2.0.0"
  },
  "logging": {
    "threshold": "info"
  },
  "core": {
    "announce_policy": {
      "interval": 120,
      "interval_min": 120
    },
    "database": {
      "driver": "sqlite3",
      "path": "./integration_tests_sqlite3.db"
    },
    "inactive_peer_cleanup_interval": 600,
    "listed": false,
    "net": {
      "external_ip": "0.0.0.0",
      "on_reverse_proxy": false
    },
    "private": false,
    "private_mode": null,
    "tracker_policy": {
      "max_peer_timeout": 900,
      "persistent_torrent_completed_stat": false,
      "remove_peerless_torrents": true
    },
    "tracker_usage_statistics": true
  },
  "udp_trackers": null,
  "http_trackers": null,
  "http_api": null,
  "health_check_api": {
    "bind_address": "0.0.0.0:0"
  }
}
2025-04-04T09:56:36.115238Z  INFO torrust_tracker_lib::bootstrap::app: Configuration:
{
  "metadata": {
    "app": "torrust-tracker",
    "purpose": "configuration",
    "schema_version": "2.0.0"
  },
  "logging": {
    "threshold": "info"
  },
  "core": {
    "announce_policy": {
      "interval": 120,
      "interval_min": 120
    },
    "database": {
      "driver": "sqlite3",
      "path": "./integration_tests_sqlite3.db"
    },
    "inactive_peer_cleanup_interval": 600,
    "listed": false,
    "net": {
      "external_ip": "0.0.0.0",
      "on_reverse_proxy": false
    },
    "private": false,
    "private_mode": null,
    "tracker_policy": {
      "max_peer_timeout": 900,
      "persistent_torrent_completed_stat": false,
      "remove_peerless_torrents": true
    },
    "tracker_usage_statistics": true
  },
  "udp_trackers": null,
  "http_trackers": null,
  "http_api": null,
  "health_check_api": {
    "bind_address": "0.0.0.0:0"
  }
}
2025-04-04T09:56:36.116667Z  WARN start: torrust_tracker_lib::app: No services enabled in configuration
2025-04-04T09:56:36.116675Z  INFO start: torrust_tracker_lib::app: No UDP blocks in configuration
2025-04-04T09:56:36.116667Z  WARN start: torrust_tracker_lib::app: No services enabled in configuration
2025-04-04T09:56:36.116685Z  INFO start: torrust_tracker_lib::app: No UDP blocks in configuration
2025-04-04T09:56:36.116679Z  INFO start: torrust_tracker_lib::app: No HTTP blocks in configuration
2025-04-04T09:56:36.116693Z  INFO start: torrust_tracker_lib::app: No API block in configuration
2025-04-04T09:56:36.116688Z  INFO start: torrust_tracker_lib::app: No HTTP blocks in configuration
2025-04-04T09:56:36.116702Z  INFO start: torrust_tracker_lib::app: No API block in configuration
2025-04-04T09:56:36.116731Z  INFO HEALTH CHECK API: Starting on: http://0.0.0.0:0
2025-04-04T09:56:36.116732Z  INFO HEALTH CHECK API: Starting on: http://0.0.0.0:0
2025-04-04T09:56:36.116879Z  INFO start:start_job: HEALTH CHECK API: Started on: http://0.0.0.0:40813
2025-04-04T09:56:36.116879Z  INFO start:start_job: HEALTH CHECK API: Started on: http://0.0.0.0:43429
test servers::api::contract::stats::the_stats_api_endpoint_should_return_the_global_stats_1 ... ok
test servers::api::contract::stats::the_stats_api_endpoint_should_return_the_global_stats_2 ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

   Doc-tests torrust_tracker_lib

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

I guess the unique initialization of the logging is working fine in this case. I don't remember why we had a problem with this in the past in other tests or why I got the error "duplication initialization of the global subscriber" while I was working on the integration test. Anyway, for now, I have removed the problem from the list.