LibTimeZone: Add a unit test for generated time zone data

Meta/Lagom/CMakeLists.txt

@@ -576,6 +576,15 @@ if (BUILD_LAGOM)
                 WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/../../Tests/LibTLS)
         endforeach()
 
+        # TimeZone
+        file(GLOB LIBTIMEZONE_TEST_SOURCES CONFIGURE_DEPENDS "../../Tests/LibTimeZone/*.cpp")
+        foreach(source ${LIBTIMEZONE_TEST_SOURCES})
+            lagom_test(${source} LIBS LagomTimeZone)
+
+            get_filename_component(target "${source}" NAME_WLE)
+            target_compile_definitions("${target}_lagom" PRIVATE ENABLE_TIME_ZONE_DATA=$<BOOL:${ENABLE_TIME_ZONE_DATABASE_DOWNLOAD}>)
+        endforeach()
+
         # Unicode
         file(GLOB LIBUNICODE_TEST_SOURCES CONFIGURE_DEPENDS "../../Tests/LibUnicode/*.cpp")
         foreach(source ${LIBUNICODE_TEST_SOURCES})

Tests/CMakeLists.txt

@@ -17,6 +17,7 @@ add_subdirectory(LibRegex)
 add_subdirectory(LibSQL)
 add_subdirectory(LibTest)
 add_subdirectory(LibThreading)
+add_subdirectory(LibTimeZone)
 add_subdirectory(LibUnicode)
 add_subdirectory(LibWasm)
 add_subdirectory(LibWeb)

Tests/LibTimeZone/CMakeLists.txt

@@ -0,0 +1,10 @@
+set(TEST_SOURCES
+    TestTimeZone.cpp
+)
+
+foreach(source IN LISTS TEST_SOURCES)
+    serenity_test("${source}" LibTimeZone LIBS LibTimeZone)
+
+    get_filename_component(target "${source}" NAME_WLE)
+    target_compile_definitions("${target}" PRIVATE ENABLE_TIME_ZONE_DATA=$<BOOL:${ENABLE_TIME_ZONE_DATABASE_DOWNLOAD}>)
+endforeach()

Tests/LibTimeZone/TestTimeZone.cpp

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2022, Tim Flynn <trflynn89@pm.me>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibTest/TestCase.h>
+
+#include <AK/StringView.h>
+#include <LibTimeZone/TimeZone.h>
+
+#if ENABLE_TIME_ZONE_DATA
+
+#    include <LibTimeZone/TimeZoneData.h>
+
+TEST_CASE(time_zone_from_string)
+{
+    EXPECT_EQ(TimeZone::time_zone_from_string("America/New_York"sv), TimeZone::TimeZone::America_New_York);
+    EXPECT_EQ(TimeZone::time_zone_from_string("Europe/Paris"sv), TimeZone::TimeZone::Europe_Paris);
+    EXPECT_EQ(TimeZone::time_zone_from_string("Etc/GMT+2"sv), TimeZone::TimeZone::Etc_GMT_Ahead_2);
+    EXPECT_EQ(TimeZone::time_zone_from_string("Etc/GMT-5"sv), TimeZone::TimeZone::Etc_GMT_Behind_5);
+
+    EXPECT(!TimeZone::time_zone_from_string("I don't exist"sv).has_value());
+}
+
+TEST_CASE(time_zone_from_string_link)
+{
+    auto test_link = [](auto tz1, auto tz2) {
+        auto result1 = TimeZone::time_zone_from_string(tz1);
+        EXPECT(result1.has_value());
+
+        auto result2 = TimeZone::time_zone_from_string(tz2);
+        EXPECT(result2.has_value());
+
+        EXPECT_EQ(*result1, *result2);
+    };
+
+    test_link("America/New_York"sv, "US/Eastern"sv);
+
+    test_link("Etc/GMT"sv, "GMT"sv);
+    test_link("Etc/GMT+0"sv, "GMT"sv);
+    test_link("Etc/GMT-0"sv, "GMT"sv);
+
+    test_link("Etc/UTC"sv, "UTC"sv);
+    test_link("Etc/Universal"sv, "UTC"sv);
+    test_link("Universal"sv, "UTC"sv);
+}
+
+#endif