Tests: Add a basic UTF-8 to UTF-8 LibTextCodec test

Author: krkk

Meta/Lagom/CMakeLists.txt

@@ -596,6 +596,13 @@ if (BUILD_LAGOM)
             lagom_test(${source} LIBS LagomSQL)
         endforeach()
 
+        # TextCodec
+        file(GLOB LIBTEXTCODEC_TESTS CONFIGURE_DEPENDS "../../Tests/LibTextCodec/*.cpp")
+        foreach(source ${LIBTEXTCODEC_TESTS})
+            lagom_test(${source} LIBS LagomTextCodec
+                WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/../../Tests/LibTextCodec)
+        endforeach()
+
         # TLS
         file(GLOB LIBTLS_TESTS CONFIGURE_DEPENDS "../../Tests/LibTLS/*.cpp")
         foreach(source ${LIBTLS_TESTS})

Tests/CMakeLists.txt

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

Tests/LibTextCodec/CMakeLists.txt

@@ -0,0 +1,7 @@
+set(TEST_SOURCES
+    TestTextDecoders.cpp
+)
+
+foreach(source IN LISTS TEST_SOURCES)
+    serenity_test("${source}" LibTextCodec LIBS LibTextCodec)
+endforeach()

Tests/LibTextCodec/TestTextDecoders.cpp

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2022, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Vector.h>
+#include <LibTest/TestCase.h>
+#include <LibTextCodec/Decoder.h>
+
+TEST_CASE(test_utf8_decode)
+{
+    auto decoder = TextCodec::UTF8Decoder();
+    // Bytes for U+1F600 GRINNING FACE
+    auto test_string = "\xf0\x9f\x98\x80";
+
+    Vector<u32> processed_code_points;
+    decoder.process(test_string, [&](u32 code_point) {
+        processed_code_points.append(code_point);
+    });
+    EXPECT(processed_code_points.size() == 1);
+    EXPECT(processed_code_points[0] == 0x1F600);
+
+    EXPECT(decoder.to_utf8(test_string) == test_string);
+}