6 files changed, 1091 insertions, 0 deletions
diff --git a/intl/l10n/rust/l10nregistry-tests/tests/localization.rs b/intl/l10n/rust/l10nregistry-tests/tests/localization.rs
new file mode 100644
index 0000000000..1362fc030e
--- /dev/null
+++ b/intl/l10n/rust/l10nregistry-tests/tests/localization.rs
@@ -0,0 +1,201 @@
+use std::borrow::Cow;
+
+use fluent_fallback::{
+    env::LocalesProvider,
+    types::{L10nKey, ResourceId},
+    Localization,
+};
+use l10nregistry_tests::{
+    FileSource, MockBundleAdapter, RegistrySetup, TestEnvironment, TestFileFetcher,
+};
+use serial_test::serial;
+use unic_langid::{langid, LanguageIdentifier};
+
+type L10nRegistry = l10nregistry::registry::L10nRegistry<TestEnvironment, MockBundleAdapter>;
+
+static LOCALES: &[LanguageIdentifier] = &[langid!("pl"), langid!("en-US")];
+static mut FILE_FETCHER: Option<TestFileFetcher> = None;
+static mut L10N_REGISTRY: Option<L10nRegistry> = None;
+
+const FTL_RESOURCE: &str = "toolkit/updates/history.ftl";
+const L10N_ID_PL_EN: (&str, Option<&str>) = ("history-title", Some("Historia aktualizacji"));
+const L10N_ID_MISSING: (&str, Option<&str>) = ("missing-id", None);
+const L10N_ID_ONLY_EN: (&str, Option<&str>) = (
+    "history-intro",
+    Some("The following updates have been installed"),
+);
+
+fn get_file_fetcher() -> &'static TestFileFetcher {
+    let fetcher: &mut Option<TestFileFetcher> = unsafe { &mut FILE_FETCHER };
+
+    fetcher.get_or_insert_with(|| TestFileFetcher::new())
+}
+
+fn get_l10n_registry() -> &'static L10nRegistry {
+    let reg: &mut Option<L10nRegistry> = unsafe { &mut L10N_REGISTRY };
+
+    reg.get_or_insert_with(|| {
+        let fetcher = get_file_fetcher();
+        let setup = RegistrySetup::new(
+            "test",
+            vec![
+                FileSource::new(
+                    "toolkit",
+                    None,
+                    get_app_locales().to_vec(),
+                    "toolkit/{locale}/",
+                ),
+                FileSource::new(
+                    "browser",
+                    None,
+                    get_app_locales().to_vec(),
+                    "browser/{locale}/",
+                ),
+            ],
+            get_app_locales().to_vec(),
+        );
+        fetcher.get_registry_and_environment(setup).1
+    })
+}
+
+fn get_app_locales() -> &'static [LanguageIdentifier] {
+    LOCALES
+}
+
+struct LocalesService;
+
+impl LocalesProvider for LocalesService {
+    type Iter = std::vec::IntoIter<LanguageIdentifier>;
+
+    fn locales(&self) -> Self::Iter {
+        get_app_locales().to_vec().into_iter()
+    }
+}
+
+fn sync_localization(
+    reg: &'static L10nRegistry,
+    res_ids: Vec<ResourceId>,
+) -> Localization<L10nRegistry, LocalesService> {
+    Localization::with_env(res_ids, true, LocalesService, reg.clone())
+}
+
+fn async_localization(
+    reg: &'static L10nRegistry,
+    res_ids: Vec<ResourceId>,
+) -> Localization<L10nRegistry, LocalesService> {
+    Localization::with_env(res_ids, false, LocalesService, reg.clone())
+}
+
+fn setup_sync_test() -> Localization<L10nRegistry, LocalesService> {
+    sync_localization(get_l10n_registry(), vec![FTL_RESOURCE.into()])
+}
+
+fn setup_async_test() -> Localization<L10nRegistry, LocalesService> {
+    async_localization(get_l10n_registry(), vec![FTL_RESOURCE.into()])
+}
+
+#[test]
+#[serial]
+fn localization_format_value_sync() {
+    let loc = setup_sync_test();
+    let bundles = loc.bundles();
+    let mut errors = vec![];
+
+    for query in &[L10N_ID_PL_EN, L10N_ID_MISSING, L10N_ID_ONLY_EN] {
+        let value = bundles
+            .format_value_sync(query.0, None, &mut errors)
+            .unwrap();
+        assert_eq!(value, query.1.map(|s| Cow::Borrowed(s)));
+    }
+
+    assert_eq!(errors.len(), 4);
+}
+
+#[test]
+#[serial]
+fn localization_format_values_sync() {
+    let loc = setup_sync_test();
+    let bundles = loc.bundles();
+    let mut errors = vec![];
+
+    let ids = &[L10N_ID_PL_EN, L10N_ID_MISSING, L10N_ID_ONLY_EN];
+    let keys = ids
+        .iter()
+        .map(|query| L10nKey {
+            id: query.0.into(),
+            args: None,
+        })
+        .collect::<Vec<_>>();
+
+    let values = bundles.format_values_sync(&keys, &mut errors).unwrap();
+
+    assert_eq!(values.len(), ids.len());
+
+    for (value, query) in values.iter().zip(ids) {
+        if let Some(expected) = query.1 {
+            assert_eq!(*value, Some(Cow::Borrowed(expected)));
+        }
+    }
+    assert_eq!(errors.len(), 4);
+}
+
+#[tokio::test]
+#[serial]
+async fn localization_format_value_async() {
+    let loc = setup_async_test();
+    let bundles = loc.bundles();
+    let mut errors = vec![];
+
+    for query in &[L10N_ID_PL_EN, L10N_ID_MISSING, L10N_ID_ONLY_EN] {
+        let value = bundles.format_value(query.0, None, &mut errors).await;
+        if let Some(expected) = query.1 {
+            assert_eq!(value, Some(Cow::Borrowed(expected)));
+        }
+    }
+}
+
+#[tokio::test]
+#[serial]
+async fn localization_format_values_async() {
+    let loc = setup_async_test();
+    let bundles = loc.bundles();
+    let mut errors = vec![];
+
+    let ids = &[L10N_ID_PL_EN, L10N_ID_MISSING, L10N_ID_ONLY_EN];
+    let keys = ids
+        .iter()
+        .map(|query| L10nKey {
+            id: query.0.into(),
+            args: None,
+        })
+        .collect::<Vec<_>>();
+
+    let values = bundles.format_values(&keys, &mut errors).await;
+
+    assert_eq!(values.len(), ids.len());
+
+    for (value, query) in values.iter().zip(ids) {
+        if let Some(expected) = query.1 {
+            assert_eq!(*value, Some(Cow::Borrowed(expected)));
+        }
+    }
+}
+
+#[tokio::test]
+#[serial]
+async fn localization_upgrade() {
+    let mut loc = setup_sync_test();
+    let bundles = loc.bundles();
+    let mut errors = vec![];
+    let value = bundles
+        .format_value_sync(L10N_ID_PL_EN.0, None, &mut errors)
+        .unwrap();
+    assert_eq!(value, L10N_ID_PL_EN.1.map(|s| Cow::Borrowed(s)));
+
+    loc.set_async();
+    let bundles = loc.bundles();
+    let value = bundles
+        .format_value(L10N_ID_PL_EN.0, None, &mut errors)
+        .await;
+    assert_eq!(value, L10N_ID_PL_EN.1.map(|s| Cow::Borrowed(s)));
+}
diff --git a/intl/l10n/rust/l10nregistry-tests/tests/registry.rs b/intl/l10n/rust/l10nregistry-tests/tests/registry.rs
new file mode 100644
index 0000000000..72d6e6ed8b
--- /dev/null
+++ b/intl/l10n/rust/l10nregistry-tests/tests/registry.rs
@@ -0,0 +1,304 @@
+use l10nregistry_tests::{FileSource, RegistrySetup, TestFileFetcher};
+use unic_langid::LanguageIdentifier;
+
+static FTL_RESOURCE_TOOLKIT: &str = "toolkit/global/textActions.ftl";
+static FTL_RESOURCE_BROWSER: &str = "branding/brand.ftl";
+
+#[test]
+fn test_get_sources_for_resource() {
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/"),
+            FileSource::new("browser", None, vec![en_us.clone()], "browser/{locale}/"),
+        ],
+        vec![en_us.clone()],
+    );
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    {
+        let metasources = reg
+            .try_borrow_metasources()
+            .expect("Unable to borrow metasources.");
+
+        let toolkit = metasources.file_source_by_name(0, "toolkit").unwrap();
+        let browser = metasources.file_source_by_name(0, "browser").unwrap();
+        let toolkit_resource_id = FTL_RESOURCE_TOOLKIT.into();
+
+        let mut i = metasources.get_sources_for_resource(0, &en_us, &toolkit_resource_id);
+
+        assert_eq!(i.next(), Some(toolkit));
+        assert_eq!(i.next(), Some(browser));
+        assert_eq!(i.next(), None);
+
+        assert!(browser
+            .fetch_file_sync(&en_us, &FTL_RESOURCE_TOOLKIT.into(), false)
+            .is_none());
+
+        let mut i = metasources.get_sources_for_resource(0, &en_us, &toolkit_resource_id);
+        assert_eq!(i.next(), Some(toolkit));
+        assert_eq!(i.next(), None);
+
+        assert!(toolkit
+            .fetch_file_sync(&en_us, &FTL_RESOURCE_TOOLKIT.into(), false)
+            .is_some());
+
+        let mut i = metasources.get_sources_for_resource(0, &en_us, &toolkit_resource_id);
+        assert_eq!(i.next(), Some(toolkit));
+        assert_eq!(i.next(), None);
+    }
+}
+
+#[test]
+fn test_generate_bundles_for_lang_sync() {
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/"),
+            FileSource::new("browser", None, vec![en_us.clone()], "browser/{locale}/"),
+        ],
+        vec![en_us.clone()],
+    );
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let mut i = reg.generate_bundles_for_lang_sync(en_us.clone(), paths);
+
+    assert!(i.next().is_some());
+    assert!(i.next().is_none());
+}
+
+#[test]
+fn test_generate_bundles_sync() {
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/"),
+            FileSource::new("browser", None, vec![en_us.clone()], "browser/{locale}/"),
+        ],
+        vec![en_us.clone()],
+    );
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let lang_ids = vec![en_us];
+    let mut i = reg.generate_bundles_sync(lang_ids.into_iter(), paths);
+
+    assert!(i.next().is_some());
+    assert!(i.next().is_none());
+}
+
+#[tokio::test]
+async fn test_generate_bundles_for_lang() {
+    use futures::stream::StreamExt;
+
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/"),
+            FileSource::new("browser", None, vec![en_us.clone()], "browser/{locale}/"),
+        ],
+        vec![en_us.clone()],
+    );
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let mut i = reg
+        .generate_bundles_for_lang(en_us, paths)
+        .expect("Failed to get GenerateBundles.");
+
+    assert!(i.next().await.is_some());
+    assert!(i.next().await.is_none());
+}
+
+#[tokio::test]
+async fn test_generate_bundles() {
+    use futures::stream::StreamExt;
+
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/"),
+            FileSource::new("browser", None, vec![en_us.clone()], "browser/{locale}/"),
+        ],
+        vec![en_us.clone()],
+    );
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let langs = vec![en_us];
+    let mut i = reg
+        .generate_bundles(langs.into_iter(), paths)
+        .expect("Failed to get GenerateBundles.");
+
+    assert!(i.next().await.is_some());
+    assert!(i.next().await.is_none());
+}
+
+#[test]
+fn test_manage_sources() {
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/"),
+            FileSource::new("browser", None, vec![en_us.clone()], "browser/{locale}/"),
+        ],
+        vec![en_us.clone()],
+    );
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    let lang_ids = vec![en_us];
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+
+    let mut i = reg.generate_bundles_sync(lang_ids.clone().into_iter(), paths);
+
+    assert!(i.next().is_some());
+    assert!(i.next().is_none());
+
+    reg.clone()
+        .remove_sources(vec!["toolkit"])
+        .expect("Failed to remove a source.");
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let mut i = reg.generate_bundles_sync(lang_ids.clone().into_iter(), paths);
+    assert!(i.next().is_none());
+
+    let paths = vec![FTL_RESOURCE_BROWSER.into()];
+    let mut i = reg.generate_bundles_sync(lang_ids.clone().into_iter(), paths);
+    assert!(i.next().is_some());
+    assert!(i.next().is_none());
+
+    reg.register_sources(vec![fetcher.get_test_file_source(
+        "toolkit",
+        None,
+        lang_ids.clone(),
+        "browser/{locale}/",
+    )])
+    .expect("Failed to register a source.");
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let mut i = reg.generate_bundles_sync(lang_ids.clone().into_iter(), paths);
+    assert!(i.next().is_none());
+
+    reg.update_sources(vec![fetcher.get_test_file_source(
+        "toolkit",
+        None,
+        lang_ids.clone(),
+        "toolkit/{locale}/",
+    )])
+    .expect("Failed to update a source.");
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let mut i = reg.generate_bundles_sync(lang_ids.clone().into_iter(), paths);
+    assert!(i.next().is_some());
+    assert!(i.next().is_none());
+}
+
+#[test]
+fn test_generate_bundles_with_metasources_sync() {
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new(
+                "toolkit",
+                Some("app"),
+                vec![en_us.clone()],
+                "toolkit/{locale}/",
+            ),
+            FileSource::new(
+                "browser",
+                Some("app"),
+                vec![en_us.clone()],
+                "browser/{locale}/",
+            ),
+            FileSource::new(
+                "toolkit",
+                Some("langpack"),
+                vec![en_us.clone()],
+                "toolkit/{locale}/",
+            ),
+            FileSource::new(
+                "browser",
+                Some("langpack"),
+                vec![en_us.clone()],
+                "browser/{locale}/",
+            ),
+        ],
+        vec![en_us.clone()],
+    );
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let lang_ids = vec![en_us];
+    let mut i = reg.generate_bundles_sync(lang_ids.into_iter(), paths);
+
+    assert!(i.next().is_some());
+    assert!(i.next().is_some());
+    assert!(i.next().is_none());
+}
+
+#[tokio::test]
+async fn test_generate_bundles_with_metasources() {
+    use futures::stream::StreamExt;
+
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+
+    let setup = RegistrySetup::new(
+        "test",
+        vec![
+            FileSource::new(
+                "toolkit",
+                Some("app"),
+                vec![en_us.clone()],
+                "toolkit/{locale}/",
+            ),
+            FileSource::new(
+                "browser",
+                Some("app"),
+                vec![en_us.clone()],
+                "browser/{locale}/",
+            ),
+            FileSource::new(
+                "toolkit",
+                Some("langpack"),
+                vec![en_us.clone()],
+                "toolkit/{locale}/",
+            ),
+            FileSource::new(
+                "browser",
+                Some("langpack"),
+                vec![en_us.clone()],
+                "browser/{locale}/",
+            ),
+        ],
+        vec![en_us.clone()],
+    );
+
+    let fetcher = TestFileFetcher::new();
+    let (_, reg) = fetcher.get_registry_and_environment(setup);
+
+    let paths = vec![FTL_RESOURCE_TOOLKIT.into(), FTL_RESOURCE_BROWSER.into()];
+    let langs = vec![en_us];
+    let mut i = reg
+        .generate_bundles(langs.into_iter(), paths)
+        .expect("Failed to get GenerateBundles.");
+
+    assert!(i.next().await.is_some());
+    assert!(i.next().await.is_some());
+    assert!(i.next().await.is_none());
+}
diff --git a/intl/l10n/rust/l10nregistry-tests/tests/scenarios_async.rs b/intl/l10n/rust/l10nregistry-tests/tests/scenarios_async.rs
new file mode 100644
index 0000000000..cdbf373d84
--- /dev/null
+++ b/intl/l10n/rust/l10nregistry-tests/tests/scenarios_async.rs
@@ -0,0 +1,109 @@
+use fluent_bundle::FluentArgs;
+use fluent_fallback::Localization;
+use fluent_testing::get_scenarios;
+use l10nregistry::fluent::FluentBundle;
+use l10nregistry::registry::BundleAdapter;
+use l10nregistry_tests::{RegistrySetup, TestFileFetcher};
+
+#[derive(Clone)]
+struct ScenarioBundleAdapter {}
+
+impl BundleAdapter for ScenarioBundleAdapter {
+    fn adapt_bundle(&self, bundle: &mut FluentBundle) {
+        bundle.set_use_isolating(false);
+        bundle
+            .add_function("PLATFORM", |_positional, _named| "linux".into())
+            .expect("Failed to add a function to the bundle.");
+    }
+}
+
+#[tokio::test]
+async fn scenarios_async() {
+    use fluent_testing::scenarios::structs::Scenario;
+    let fetcher = TestFileFetcher::new();
+
+    let scenarios = get_scenarios();
+
+    let adapter = ScenarioBundleAdapter {};
+
+    let cannot_produce_bundle = |scenario: &Scenario| {
+        scenario
+            .queries
+            .iter()
+            .any(|query| query.exceptional_context.blocks_bundle_generation())
+    };
+
+    for scenario in scenarios {
+        println!("scenario: {}", scenario.name);
+        let setup: RegistrySetup = (&scenario).into();
+        let (env, reg) = fetcher.get_registry_and_environment_with_adapter(setup, adapter.clone());
+
+        let loc = Localization::with_env(scenario.res_ids.clone(), false, env.clone(), reg);
+        let bundles = loc.bundles();
+        let no_bundles = cannot_produce_bundle(&scenario);
+
+        let mut errors = vec![];
+
+        for query in scenario.queries.iter() {
+            let errors_start_len = errors.len();
+
+            let args = query.input.args.as_ref().map(|args| {
+                let mut result = FluentArgs::new();
+                for arg in args.as_slice() {
+                    result.set(arg.id.clone(), arg.value.clone());
+                }
+                result
+            });
+
+            if let Some(output) = &query.output {
+                if let Some(value) = &output.value {
+                    let v = bundles
+                        .format_value(&query.input.id, args.as_ref(), &mut errors)
+                        .await;
+                    if no_bundles || query.exceptional_context.causes_failed_value_lookup() {
+                        assert!(v.is_none());
+                        if no_bundles {
+                            continue;
+                        }
+                    } else {
+                        assert_eq!(v.unwrap(), value.as_str())
+                    }
+                }
+            }
+
+            if query.exceptional_context.causes_reported_format_error() {
+                assert!(
+                    errors.len() > errors_start_len,
+                    "expected reported errors for query {:#?}",
+                    query
+                );
+            } else {
+                assert_eq!(
+                    errors.len(),
+                    errors_start_len,
+                    "expected no reported errors for query {:#?}",
+                    query
+                );
+            }
+        }
+
+        if scenario
+            .queries
+            .iter()
+            .any(|query| query.exceptional_context.missing_required_resource())
+        {
+            assert!(
+                !env.errors().is_empty(),
+                "expected errors for scenario {{ {} }}, but found none",
+                scenario.name
+            );
+        } else {
+            assert!(
+                env.errors().is_empty(),
+                "expected no errors for scenario {{ {} }}, but found {:#?}",
+                scenario.name,
+                env.errors()
+            );
+        }
+    }
+}
diff --git a/intl/l10n/rust/l10nregistry-tests/tests/scenarios_sync.rs b/intl/l10n/rust/l10nregistry-tests/tests/scenarios_sync.rs
new file mode 100644
index 0000000000..ce13b241fe
--- /dev/null
+++ b/intl/l10n/rust/l10nregistry-tests/tests/scenarios_sync.rs
@@ -0,0 +1,107 @@
+use fluent_bundle::FluentArgs;
+use fluent_fallback::Localization;
+use fluent_testing::get_scenarios;
+use l10nregistry::fluent::FluentBundle;
+use l10nregistry::registry::BundleAdapter;
+use l10nregistry_tests::{RegistrySetup, TestFileFetcher};
+
+#[derive(Clone)]
+struct ScenarioBundleAdapter {}
+
+impl BundleAdapter for ScenarioBundleAdapter {
+    fn adapt_bundle(&self, bundle: &mut FluentBundle) {
+        bundle.set_use_isolating(false);
+        bundle
+            .add_function("PLATFORM", |_positional, _named| "linux".into())
+            .expect("Failed to add a function to the bundle.");
+    }
+}
+
+#[test]
+fn scenarios_sync() {
+    use fluent_testing::scenarios::structs::Scenario;
+    let fetcher = TestFileFetcher::new();
+
+    let scenarios = get_scenarios();
+
+    let adapter = ScenarioBundleAdapter {};
+
+    let cannot_produce_bundle = |scenario: &Scenario| {
+        scenario
+            .queries
+            .iter()
+            .any(|query| query.exceptional_context.blocks_bundle_generation())
+    };
+
+    for scenario in scenarios {
+        println!("scenario: {}", scenario.name);
+        let setup: RegistrySetup = (&scenario).into();
+        let (env, reg) = fetcher.get_registry_and_environment_with_adapter(setup, adapter.clone());
+
+        let loc = Localization::with_env(scenario.res_ids.clone(), true, env.clone(), reg);
+        let bundles = loc.bundles();
+        let no_bundles = cannot_produce_bundle(&scenario);
+
+        let mut errors = vec![];
+
+        for query in scenario.queries.iter() {
+            let errors_start_len = errors.len();
+
+            let args = query.input.args.as_ref().map(|args| {
+                let mut result = FluentArgs::new();
+                for arg in args.as_slice() {
+                    result.set(arg.id.clone(), arg.value.clone());
+                }
+                result
+            });
+
+            if let Some(output) = &query.output {
+                if let Some(value) = &output.value {
+                    let v = bundles.format_value_sync(&query.input.id, args.as_ref(), &mut errors);
+                    if no_bundles || query.exceptional_context.causes_failed_value_lookup() {
+                        assert!(v.is_err() || v.unwrap().is_none());
+                        if no_bundles {
+                            continue;
+                        }
+                    } else {
+                        assert_eq!(v.unwrap().unwrap(), value.as_str())
+                    }
+                }
+            }
+
+            if query.exceptional_context.causes_reported_format_error() {
+                assert!(
+                    errors.len() > errors_start_len,
+                    "expected reported errors for query {:#?}",
+                    query
+                );
+            } else {
+                assert_eq!(
+                    errors.len(),
+                    errors_start_len,
+                    "expected no reported errors for query {:#?}",
+                    query
+                );
+            }
+        }
+
+        if scenario
+            .queries
+            .iter()
+            .any(|query| query.exceptional_context.missing_required_resource())
+        {
+            assert!(
+                !env.errors().is_empty(),
+                "expected errors for scenario {{ {} }}, but found none",
+                scenario.name
+            );
+        } else {
+            assert!(
+                env.errors().is_empty(),
+                "expected no errors for scenario {{ {} }}, but found {:#?}",
+                scenario.name,
+                env.errors()
+            );
+        }
+    }
+}
diff --git a/intl/l10n/rust/l10nregistry-tests/tests/source.rs b/intl/l10n/rust/l10nregistry-tests/tests/source.rs
new file mode 100644
index 0000000000..63104db8eb
--- /dev/null
+++ b/intl/l10n/rust/l10nregistry-tests/tests/source.rs
@@ -0,0 +1,305 @@
+use fluent_fallback::types::{ResourceType, ToResourceId};
+use futures::future::join_all;
+use l10nregistry_tests::TestFileFetcher;
+use unic_langid::LanguageIdentifier;
+
+static FTL_RESOURCE_PRESENT: &str = "toolkit/global/textActions.ftl";
+static FTL_RESOURCE_MISSING: &str = "missing.ftl";
+
+#[test]
+fn test_fetch_sync() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let file = fs1.fetch_file_sync(&en_us, &FTL_RESOURCE_PRESENT.into(), false);
+    assert!(file.is_some());
+    assert!(!file.is_none());
+    assert!(!file.is_required_and_missing());
+
+    let file = fs1.fetch_file_sync(
+        &en_us,
+        &FTL_RESOURCE_PRESENT.to_resource_id(ResourceType::Required),
+        false,
+    );
+    assert!(file.is_some());
+    assert!(!file.is_none());
+    assert!(!file.is_required_and_missing());
+
+    let file = fs1.fetch_file_sync(
+        &en_us,
+        &FTL_RESOURCE_PRESENT.to_resource_id(ResourceType::Optional),
+        false,
+    );
+    assert!(file.is_some());
+    assert!(!file.is_none());
+    assert!(!file.is_required_and_missing());
+
+    let file = fs1.fetch_file_sync(&en_us, &FTL_RESOURCE_MISSING.into(), false);
+    assert!(!file.is_some());
+    assert!(file.is_none());
+    assert!(file.is_required_and_missing());
+
+    let file = fs1.fetch_file_sync(
+        &en_us,
+        &FTL_RESOURCE_MISSING.to_resource_id(ResourceType::Required),
+        false,
+    );
+    assert!(!file.is_some());
+    assert!(file.is_none());
+    assert!(file.is_required_and_missing());
+
+    let file = fs1.fetch_file_sync(
+        &en_us,
+        &FTL_RESOURCE_MISSING.to_resource_id(ResourceType::Optional),
+        false,
+    );
+    assert!(!file.is_some());
+    assert!(file.is_none());
+    assert!(!file.is_required_and_missing());
+}
+
+#[tokio::test]
+async fn test_fetch_async() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let file = fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into()).await;
+    assert!(file.is_some());
+    assert!(!file.is_none());
+    assert!(!file.is_required_and_missing());
+
+    let file = fs1
+        .fetch_file(
+            &en_us,
+            &FTL_RESOURCE_PRESENT.to_resource_id(ResourceType::Required),
+        )
+        .await;
+    assert!(file.is_some());
+    assert!(!file.is_none());
+    assert!(!file.is_required_and_missing());
+
+    let file = fs1
+        .fetch_file(
+            &en_us,
+            &FTL_RESOURCE_PRESENT.to_resource_id(ResourceType::Optional),
+        )
+        .await;
+    assert!(file.is_some());
+    assert!(!file.is_none());
+    assert!(!file.is_required_and_missing());
+
+    let file = fs1.fetch_file(&en_us, &FTL_RESOURCE_MISSING.into()).await;
+    assert!(!file.is_some());
+    assert!(file.is_none());
+    assert!(file.is_required_and_missing());
+
+    let file = fs1
+        .fetch_file(
+            &en_us,
+            &FTL_RESOURCE_MISSING.to_resource_id(ResourceType::Required),
+        )
+        .await;
+    assert!(!file.is_some());
+    assert!(file.is_none());
+    assert!(file.is_required_and_missing());
+
+    let file = fs1
+        .fetch_file(
+            &en_us,
+            &FTL_RESOURCE_MISSING.to_resource_id(ResourceType::Optional),
+        )
+        .await;
+    assert!(!file.is_some());
+    assert!(file.is_none());
+    assert!(!file.is_required_and_missing());
+}
+
+#[tokio::test]
+async fn test_fetch_sync_2_async() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    assert!(fs1
+        .fetch_file_sync(&en_us, &FTL_RESOURCE_PRESENT.into(), false)
+        .is_some());
+    assert!(fs1
+        .fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into())
+        .await
+        .is_some());
+    assert!(fs1
+        .fetch_file_sync(&en_us, &FTL_RESOURCE_PRESENT.into(), false)
+        .is_some());
+}
+
+#[tokio::test]
+async fn test_fetch_async_2_sync() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    assert!(fs1
+        .fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into())
+        .await
+        .is_some());
+    assert!(fs1
+        .fetch_file_sync(&en_us, &FTL_RESOURCE_PRESENT.into(), false)
+        .is_some());
+}
+
+#[test]
+fn test_fetch_has_value_required_sync() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let path = FTL_RESOURCE_PRESENT.into();
+    let path_missing = FTL_RESOURCE_MISSING.into();
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    assert_eq!(fs1.has_file(&en_us, &path), None);
+    assert!(fs1.fetch_file_sync(&en_us, &path, false).is_some());
+    assert_eq!(fs1.has_file(&en_us, &path), Some(true));
+
+    assert_eq!(fs1.has_file(&en_us, &path_missing), None);
+    assert!(fs1.fetch_file_sync(&en_us, &path_missing, false).is_none());
+    assert_eq!(fs1.has_file(&en_us, &path_missing), Some(false));
+}
+
+#[test]
+fn test_fetch_has_value_optional_sync() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let path = FTL_RESOURCE_PRESENT.to_resource_id(ResourceType::Optional);
+    let path_missing = FTL_RESOURCE_MISSING.to_resource_id(ResourceType::Optional);
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    assert_eq!(fs1.has_file(&en_us, &path), None);
+    assert!(fs1.fetch_file_sync(&en_us, &path, false).is_some());
+    assert_eq!(fs1.has_file(&en_us, &path), Some(true));
+
+    assert_eq!(fs1.has_file(&en_us, &path_missing), None);
+    assert!(fs1.fetch_file_sync(&en_us, &path_missing, false).is_none());
+    assert_eq!(fs1.has_file(&en_us, &path_missing), Some(false));
+}
+
+#[tokio::test]
+async fn test_fetch_has_value_required_async() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let path = FTL_RESOURCE_PRESENT.into();
+    let path_missing = FTL_RESOURCE_MISSING.into();
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    assert_eq!(fs1.has_file(&en_us, &path), None);
+    assert!(fs1.fetch_file(&en_us, &path).await.is_some());
+    println!("Completed");
+    assert_eq!(fs1.has_file(&en_us, &path), Some(true));
+
+    assert_eq!(fs1.has_file(&en_us, &path_missing), None);
+
+    assert!(fs1.fetch_file(&en_us, &path_missing).await.is_none());
+    assert!(fs1
+        .fetch_file(&en_us, &path_missing)
+        .await
+        .is_required_and_missing());
+
+    assert_eq!(fs1.has_file(&en_us, &path_missing), Some(false));
+
+    assert!(fs1.fetch_file_sync(&en_us, &path_missing, false).is_none());
+    assert!(fs1
+        .fetch_file_sync(&en_us, &path_missing, false)
+        .is_required_and_missing());
+}
+
+#[tokio::test]
+async fn test_fetch_has_value_optional_async() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let path = FTL_RESOURCE_PRESENT.to_resource_id(ResourceType::Optional);
+    let path_missing = FTL_RESOURCE_MISSING.to_resource_id(ResourceType::Optional);
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    assert_eq!(fs1.has_file(&en_us, &path), None);
+    assert!(fs1.fetch_file(&en_us, &path).await.is_some());
+    println!("Completed");
+    assert_eq!(fs1.has_file(&en_us, &path), Some(true));
+
+    assert_eq!(fs1.has_file(&en_us, &path_missing), None);
+    assert!(fs1.fetch_file(&en_us, &path_missing).await.is_none());
+    assert!(!fs1
+        .fetch_file(&en_us, &path_missing)
+        .await
+        .is_required_and_missing());
+
+    assert_eq!(fs1.has_file(&en_us, &path_missing), Some(false));
+
+    assert!(fs1.fetch_file_sync(&en_us, &path_missing, false).is_none());
+    assert!(!fs1
+        .fetch_file_sync(&en_us, &path_missing, false)
+        .is_required_and_missing());
+}
+
+#[tokio::test]
+async fn test_fetch_async_consecutive() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let results = join_all(vec![
+        fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into()),
+        fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into()),
+    ])
+    .await;
+    assert!(results[0].is_some());
+    assert!(results[1].is_some());
+
+    assert!(fs1
+        .fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into())
+        .await
+        .is_some());
+}
+
+#[test]
+fn test_indexed() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let path = FTL_RESOURCE_PRESENT;
+    let path_missing = FTL_RESOURCE_MISSING;
+
+    let fs1 = fetcher.get_test_file_source_with_index(
+        "toolkit",
+        None,
+        vec![en_us.clone()],
+        "toolkit/{locale}/",
+        vec!["toolkit/en-US/toolkit/global/textActions.ftl"],
+    );
+
+    assert_eq!(fs1.has_file(&en_us, &path.into()), Some(true));
+    assert!(fs1.fetch_file_sync(&en_us, &path.into(), false).is_some());
+    assert_eq!(fs1.has_file(&en_us, &path.into()), Some(true));
+
+    assert_eq!(fs1.has_file(&en_us, &path_missing.into()), Some(false));
+    assert!(fs1
+        .fetch_file_sync(&en_us, &path_missing.into(), false)
+        .is_none());
+    assert_eq!(fs1.has_file(&en_us, &path_missing.into()), Some(false));
+}
diff --git a/intl/l10n/rust/l10nregistry-tests/tests/tokio.rs b/intl/l10n/rust/l10nregistry-tests/tests/tokio.rs
new file mode 100644
index 0000000000..0f404c3a08
--- /dev/null
+++ b/intl/l10n/rust/l10nregistry-tests/tests/tokio.rs
@@ -0,0 +1,65 @@
+use l10nregistry_tests::TestFileFetcher;
+use unic_langid::LanguageIdentifier;
+
+static FTL_RESOURCE_PRESENT: &str = "toolkit/global/textActions.ftl";
+static FTL_RESOURCE_MISSING: &str = "missing.ftl";
+
+#[tokio::test]
+async fn file_source_fetch() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let file = fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into()).await;
+    assert!(file.is_some());
+}
+
+#[tokio::test]
+async fn file_source_fetch_missing() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let file = fs1.fetch_file(&en_us, &FTL_RESOURCE_MISSING.into()).await;
+    assert!(file.is_none());
+}
+
+#[tokio::test]
+async fn file_source_already_loaded() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let file = fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into()).await;
+    assert!(file.is_some());
+    let file = fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into()).await;
+    assert!(file.is_some());
+}
+
+#[tokio::test]
+async fn file_source_concurrent() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let file1 = fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into());
+    let file2 = fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into());
+    assert!(file1.await.is_some());
+    assert!(file2.await.is_some());
+}
+
+#[test]
+fn file_source_sync_after_async_fail() {
+    let fetcher = TestFileFetcher::new();
+    let en_us: LanguageIdentifier = "en-US".parse().unwrap();
+    let fs1 =
+        fetcher.get_test_file_source("toolkit", None, vec![en_us.clone()], "toolkit/{locale}/");
+
+    let _ = fs1.fetch_file(&en_us, &FTL_RESOURCE_PRESENT.into());
+    let file2 = fs1.fetch_file_sync(&en_us, &FTL_RESOURCE_PRESENT.into(), true);
+    assert!(file2.is_some());
+}