[fit] Enhance FIT's i18n capabilities by parsing locales from HTTP requests.

framework/fit/java/fit-builtin/plugins/fit-validation-hibernate-jakarta/src/test/java/modelengine/fitframework/validation/LocaleValidationControllerTest.java

@@ -49,7 +49,7 @@ void teardown() throws IOException {
 
     @Test
     @DisplayName("测试法文地区的验证消息")
-    void shouldReturnChineseValidationMessage() {
+    void shouldReturnFrenchValidationMessage() {
         Company invalidCompany = new Company(null);
 
         MockRequestBuilder requestBuilder = MockMvcRequestBuilders.post("/validation/locale/simple")

framework/fit/java/fit-builtin/plugins/fit-validation-hibernate-javax/src/test/java/modelengine/fitframework/validation/LocaleValidationControllerTest.java

@@ -49,7 +49,7 @@ void teardown() throws IOException {
 
     @Test
     @DisplayName("测试法文地区的验证消息")
-    void shouldReturnChineseValidationMessage() {
+    void shouldReturnFrenchValidationMessage() {
         Company invalidCompany = new Company(null);
 
         MockRequestBuilder requestBuilder = MockMvcRequestBuilders.post("/validation/locale/simple")

framework/fit/java/fit-util/src/test/java/modelengine/fitframework/util/i18n/LocaleContextHolderTest.java

@@ -0,0 +1,102 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) 2025 Huawei Technologies Co., Ltd. All rights reserved.
+ *  This file is a part of the ModelEngine Project.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+package modelengine.fitframework.util.i18n;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Locale;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+/**
+ * {@link LocaleContextHolder} 的单元测试。
+ *
+ * @author 阮睿
+ * @since 2025-09-09
+ */
+@DisplayName("测试 LocaleContextHolder")
+public class LocaleContextHolderTest {
+    @AfterEach
+    void tearDown() {
+        LocaleContextHolder.clear();
+    }
+
+    @Nested
+    @DisplayName("Test method: setLocaleContext and getLocaleContext")
+    class TestSetAndGetLocaleContext {
+
+        @Test
+        @DisplayName("Given locale context with zh_CN then return the same locale context")
+        void givenLocaleContextWithZhCNThenReturnSameLocaleContext() {
+            LocaleContext localeContext = new LocaleContext(Locale.SIMPLIFIED_CHINESE);
+            LocaleContextHolder.setLocaleContext(localeContext);
+            assertThat(LocaleContextHolder.getLocaleContext()).isEqualTo(localeContext);
+        }
+
+        @Test
+        @DisplayName("Given locale context with en_US then return the same locale context")
+        void givenLocaleContextWithEnUSThenReturnSameLocaleContext() {
+            LocaleContext localeContext = new LocaleContext(Locale.US);
+            LocaleContextHolder.setLocaleContext(localeContext);
+            assertThat(LocaleContextHolder.getLocaleContext()).isEqualTo(localeContext);
+        }
+
+        @Test
+        @DisplayName("Given null locale context then not set and return null")
+        void givenNullLocaleContextThenReturnNull() {
+            LocaleContextHolder.setLocaleContext(null);
+            assertThat(LocaleContextHolder.getLocaleContext()).isNull();
+        }
+    }
+
+    @Nested
+    @DisplayName("Test method: getLocale")
+    class TestGetLocale {
+
+        @Test
+        @DisplayName("Given locale context with zh_CN then return zh_CN locale")
+        void givenLocaleContextWithZhCNThenReturnZhCNLocale() {
+            LocaleContext localeContext = new LocaleContext(Locale.SIMPLIFIED_CHINESE);
+            LocaleContextHolder.setLocaleContext(localeContext);
+            assertThat(LocaleContextHolder.getLocale()).isEqualTo(Locale.SIMPLIFIED_CHINESE);
+        }
+
+        @Test
+        @DisplayName("Given locale context with en_US then return en_US locale")
+        void givenLocaleContextWithEnUSThenReturnEnUSLocale() {
+            LocaleContext localeContext = new LocaleContext(Locale.US);
+            LocaleContextHolder.setLocaleContext(localeContext);
+            assertThat(LocaleContextHolder.getLocale()).isEqualTo(Locale.US);
+        }
+
+        @Test
+        @DisplayName("Given no locale context then return null")
+        void givenNoLocaleContextThenReturnNull() {
+            LocaleContextHolder.clear();
+            assertThat(LocaleContextHolder.getLocale()).isNull();
+        }
+    }
+
+    @Nested
+    @DisplayName("Test method: clear")
+    class TestClear {
+
+        @Test
+        @DisplayName("Given existing locale context then clear it")
+        void givenExistingLocaleContextThenClearIt() {
+            LocaleContext localeContext = new LocaleContext(Locale.SIMPLIFIED_CHINESE);
+            LocaleContextHolder.setLocaleContext(localeContext);
+            assertThat(LocaleContextHolder.getLocaleContext()).isNotNull();
+
+            LocaleContextHolder.clear();
+            assertThat(LocaleContextHolder.getLocaleContext()).isNull();
+        }
+    }
+}

framework/fit/java/fit-util/src/test/java/modelengine/fitframework/util/i18n/LocaleContextTest.java

@@ -0,0 +1,53 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) 2025 Huawei Technologies Co., Ltd. All rights reserved.
+ *  This file is a part of the ModelEngine Project.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+package modelengine.fitframework.util.i18n;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Locale;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+/**
+ * {@link LocaleContext} 的单元测试。
+ *
+ * @author 阮睿
+ * @since 2025-09-09
+ */
+@DisplayName("测试 LocaleContext")
+public class LocaleContextTest {
+    @Nested
+    @DisplayName("Test method: constructor and getLocale()")
+    class TestConstructorAndGetLocale {
+
+        @Test
+        @DisplayName("Given locale is zh_CN then return the same locale")
+        void givenZhCNThenReturnSameLocale() {
+            Locale locale = Locale.SIMPLIFIED_CHINESE;
+            LocaleContext localeContext = new LocaleContext(locale);
+            assertThat(localeContext.getLocale()).isEqualTo(locale);
+        }
+
+        @Test
+        @DisplayName("Given locale is en_US then return the same locale")
+        void givenEnUSThenReturnSameLocale() {
+            Locale locale = Locale.US;
+            LocaleContext localeContext = new LocaleContext(locale);
+            assertThat(localeContext.getLocale()).isEqualTo(locale);
+        }
+
+        @Test
+        @DisplayName("Given locale is null then return null")
+        void givenNullThenReturnNull() {
+            LocaleContext localeContext = new LocaleContext(null);
+            assertThat(localeContext.getLocale()).isNull();
+        }
+    }
+}
+