Add unit tests.

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "tests/lib"]
+	path = tests/lib
+	url = https://github.com/google/googletest

CMakeLists.txt

@@ -25,3 +25,5 @@ if("${CMAKE_BUILD_TYPE}" MATCHES "Release")
 endif()
 
 add_library("Aaru.Checksums.Native" SHARED adler32.h adler32.c crc16.h crc16.c crc16_ccitt.h crc16_ccitt.c crc32.c crc32.h crc64.c crc64.h fletcher16.h fletcher16.c fletcher32.h fletcher32.c library.h spamsum.c spamsum.h crc32_clmul.c crc64_clmul.c simd.c simd.h adler32_ssse3.c adler32_avx2.c adler32_neon.c crc32_arm_simd.c crc32_vmull.c crc32_simd.h)
+
+add_subdirectory(tests)

tests/CMakeLists.txt

@@ -0,0 +1,14 @@
+# 'Google_test' is the subproject name
+project(tests)
+
+# 'lib' is the folder with Google Test sources
+add_subdirectory(lib)
+include_directories(${gtest_SOURCE_DIR}/include ${gtest_SOURCE_DIR})
+
+file(COPY ${CMAKE_CURRENT_SOURCE_DIR}/data/random
+     DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/data/random)
+
+# 'Google_Tests_run' is the target name
+# 'test1.cpp tests2.cpp' are source files with tests
+add_executable(tests_run crc32.cpp)
+target_link_libraries(tests_run gtest gtest_main "Aaru.Checksums.Native")

tests/crc32.cpp

@@ -0,0 +1,54 @@
+//
+// Created by claunia on 5/10/21.
+//
+
+#include <stdint.h>
+
+#include "../library.h"
+#include "../crc32.h"
+#include "gtest/gtest.h"
+
+#define EXPECTED_CRC32 0x2B6E6854
+
+const uint8_t* buffer;
+
+class crc32Fixture : public ::testing::Test
+{
+  public:
+    crc32Fixture()
+    {
+        // initialization;
+        // can also be done in SetUp()
+    }
+
+  protected:
+    void SetUp()
+    {
+        FILE* file = fopen("/home/claunia/random", "rb");
+        buffer     = (const uint8_t*)malloc(1048576);
+        fread((void*)buffer, 1, 1048576, file);
+        fclose(file);
+    }
+
+    void TearDown() { free((void*)buffer); }
+
+    ~crc32Fixture()
+    {
+        // resources cleanup, no exceptions allowed
+    }
+
+    // shared user data
+};
+
+TEST_F(crc32Fixture, crc32_auto)
+{
+    crc32_ctx* ctx = crc32_init();
+    uint32_t   crc;
+
+    EXPECT_NE(ctx, nullptr);
+
+    crc32_update(ctx, buffer, 1048576);
+    crc32_final(ctx, &crc);
+
+    EXPECT_EQ(crc, EXPECTED_CRC32);
+}