Initial commit.

Packages/Localization/Tests/Cases/Public/Methods/LocalizeTests.swift

@@ -0,0 +1,134 @@
+import Foundation
+import Testing
+
+@testable import Localization
+
+@Suite(
+    "Localize method",
+    .tags(.method)
+)
+struct LocalizeTests {
+    
+    // MARK: Constants
+    
+    private let localize = Localize(bundle: .module)
+
+    // MARK: Functional tests
+
+    @Test
+    func `resolves a key in the default locale`() {
+        let text = localize(
+            "test.greeting",
+            locale: Locale(identifier: "en")
+        )
+
+        #expect(text == "Hello")
+    }
+
+    @Test
+    func `resolves a key in another locale`() {
+        let text = localize(
+            "test.greeting",
+            locale: Locale(identifier: "de"),
+        )
+
+        #expect(text == "Hallo")
+    }
+
+    @Test
+    func `resolves a key in a regional locale`() {
+        let text = localize(
+            "test.greeting",
+            locale: Locale(identifier: "pt-BR"),
+        )
+
+        #expect(text == "Olá")
+    }
+
+    @Test
+    func `falls back to the primary language for an unmatched regional locale`() {
+        let text = localize(
+            "test.greeting",
+            locale: Locale(identifier: "de-AT"),
+        )
+
+        #expect(text == "Hallo")
+    }
+
+    @Test
+    func `falls back to the source language for an unsupported locale`() {
+        let text = localize(
+            "test.greeting",
+            locale: Locale(identifier: "fr"),
+        )
+
+        #expect(text == "Hello")
+    }
+
+    @Test
+    func `falls back to the key for an unknown entry`() {
+        let text = localize(
+            "unknown.key",
+            locale: Locale(identifier: "en"),
+        )
+
+        #expect(text == "unknown.key")
+    }
+
+    @Test
+    func `falls back to the key for a missing catalog`() {
+        let localize = Localize(bundle: .main)
+
+        let text = localize(
+            "test.greeting",
+            locale: Locale(identifier: "en")
+        )
+
+        #expect(text == "test.greeting")
+    }
+
+    // MARK: Properties tests
+
+    @Test
+    func `reports a loaded catalog`() {
+        #expect(localize.catalogState == .loaded)
+    }
+
+    @Test
+    func `reports a missing catalog`() {
+        let localize = Localize(bundle: .main)
+
+        #expect(localize.catalogState == .missing)
+    }
+
+    // A malformed catalog cannot ship as a test resource — Xcode generates string symbols for every
+    // bundled `.xcstrings` and fails the build on invalid JSON — so one is staged in a temporary
+    // directory bundle instead.
+    @Test
+    func `reports an undecodable catalog`() throws {
+        let directory = URL(fileURLWithPath: NSTemporaryDirectory())
+            .appendingPathComponent(
+                "UndecodableCatalog-\(UUID().uuidString)",
+                isDirectory: true
+            )
+
+        try FileManager.default.createDirectory(
+            at: directory,
+            withIntermediateDirectories: true
+        )
+
+        defer {
+            try? FileManager.default.removeItem(at: directory)
+        }
+
+        try Data("not a catalog".utf8).write(
+            to: directory.appendingPathComponent("Localizable.xcstrings")
+        )
+
+        let bundle = try #require(Bundle(url: directory))
+        let localize = Localize(bundle: bundle)
+
+        #expect(localize.catalogState == .undecodable)
+    }
+
+}

Packages/Localization/Tests/Cases/Public/Methods/NegotiateTests.swift

@@ -0,0 +1,130 @@
+import Foundation
+import Testing
+
+@testable import Localization
+
+@Suite(
+    "Negotiate method",
+    .tags(.method)
+)
+struct NegotiateTests {
+
+    // MARK: Constants
+
+    private let negotiate = Negotiate(bundle: .module)
+
+    // MARK: Functional tests
+
+    @Test
+    func `matches an exact language tag`() {
+        let language = negotiate(acceptLanguage: "de")
+
+        #expect(language == "de")
+    }
+
+    @Test
+    func `matches a regional language tag`() {
+        let language = negotiate(acceptLanguage: "de-AT")
+
+        #expect(language == "de")
+    }
+
+    @Test
+    func `matches a regional catalog language exactly`() {
+        let language = negotiate(acceptLanguage: "pt-BR")
+
+        #expect(language == "pt-BR")
+    }
+
+    @Test
+    func `matches a regional catalog language by its primary subtag`() {
+        let language = negotiate(acceptLanguage: "pt")
+
+        #expect(language == "pt-BR")
+    }
+
+    @Test
+    func `respects the header order of preference`() {
+        let language = negotiate(acceptLanguage: "de, en")
+
+        #expect(language == "de")
+    }
+
+    @Test
+    func `orders the language tags by descending quality weight`() {
+        let language = negotiate(acceptLanguage: "en;q=0.5, de;q=0.9")
+
+        #expect(language == "de")
+    }
+
+    @Test
+    func `treats a tag without a weight as the highest preference`() {
+        let language = negotiate(acceptLanguage: "en;q=0.9, de")
+
+        #expect(language == "de")
+    }
+
+    @Test
+    func `treats a tag with a malformed weight as the highest preference`() {
+        let language = negotiate(acceptLanguage: "en;q=0.9, de;q=broken")
+
+        #expect(language == "de")
+    }
+
+    @Test
+    func `drops language tags weighted as not acceptable`() {
+        let language = negotiate(acceptLanguage: "de;q=0, en;q=0.8")
+
+        #expect(language == "en")
+    }
+
+    @Test
+    func `falls back to the default when every tag is weighted as not acceptable`() {
+        let language = negotiate(acceptLanguage: "de;q=0, fr;q=0")
+
+        #expect(language == "en")
+    }
+
+    @Test
+    func `serves the default language for a wildcard`() {
+        let language = negotiate(acceptLanguage: "fr;q=0.9, *;q=0.5")
+
+        #expect(language == "en")
+    }
+
+    @Test
+    func `trims whitespace around the language tags`() {
+        let language = negotiate(acceptLanguage: " de , en ")
+
+        #expect(language == "de")
+    }
+
+    @Test
+    func `falls back to the default for an unsupported language`() {
+        let language = negotiate(acceptLanguage: "fr")
+
+        #expect(language == "en")
+    }
+
+    @Test
+    func `falls back to the default for a missing header`() {
+        let language = negotiate(acceptLanguage: nil)
+
+        #expect(language == "en")
+    }
+
+    @Test
+    func `falls back to the default for an empty header`() {
+        let language = negotiate(acceptLanguage: "")
+
+        #expect(language == "en")
+    }
+
+    @Test
+    func `falls back to the default for a header without language tags`() {
+        let language = negotiate(acceptLanguage: " , ;q=0.5,")
+
+        #expect(language == "en")
+    }
+
+}