diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..cbffb5c
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "tests/lib"]
+	path = tests/lib
+	url = https://github.com/google/googletest
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3ba64ad..c375f8e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,4 +8,6 @@ add_library(aaruformat SHARED include/aaruformat/consts.h include/aaruformat/enu
             include/aaruformat/decls.h include/aaruformat/structs.h src/identify.c src/open.c include/aaruformat/context.h
             src/close.c include/aaruformat/errors.h src/read.c src/crc64.c src/cst.c src/ecc_cd.c src/helpers.c)
 
-include_directories(include include/aaruformat)
\ No newline at end of file
+include_directories(include include/aaruformat)
+
+add_subdirectory(tests)
\ No newline at end of file
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 0000000..8ab387d
--- /dev/null
+++ b/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/)
+
+# 'Google_Tests_run' is the target name
+# 'test1.cpp tests2.cpp' are source files with tests
+add_executable(tests_run crc64.cpp)
+target_link_libraries(tests_run gtest gtest_main "aaruformat")
diff --git a/tests/crc64.cpp b/tests/crc64.cpp
new file mode 100644
index 0000000..6a6fddb
--- /dev/null
+++ b/tests/crc64.cpp
@@ -0,0 +1,138 @@
+//
+// Created by claunia on 5/10/21.
+//
+
+#include "../include/aaruformat.h"
+
+#include "gtest/gtest.h"
+#include <climits>
+#include <cstdint>
+#include <cstring>
+
+#define EXPECTED_CRC64 0xbf09992cc5ede38e
+#define EXPECTED_CRC64_15BYTES 0x797F3766FD93975B
+#define EXPECTED_CRC64_31BYTES 0xCD9201905A7937FD
+#define EXPECTED_CRC64_63BYTES 0x29F331FC90702BF4
+#define EXPECTED_CRC64_2352BYTES 0x126435DB43477623
+
+static const uint8_t* buffer;
+static const uint8_t* buffer_misaligned;
+
+class crc64Fixture : public ::testing::Test
+{
+  public:
+    crc64Fixture()
+    {
+        // initialization;
+        // can also be done in SetUp()
+    }
+
+  protected:
+    void SetUp()
+    {
+        char path[PATH_MAX];
+        char filename[PATH_MAX];
+
+        getcwd(path, PATH_MAX);
+        snprintf(filename, PATH_MAX, "%s/data/random", path);
+
+        FILE* file = fopen(filename, "rb");
+        buffer     = (const uint8_t*)malloc(1048576);
+        fread((void*)buffer, 1, 1048576, file);
+        fclose(file);
+
+        buffer_misaligned = (const uint8_t*)malloc(1048577);
+        memcpy((void*)(buffer_misaligned + 1), buffer, 1048576);
+    }
+
+    void TearDown()
+    {
+        free((void*)buffer);
+        free((void*)buffer_misaligned);
+    }
+
+    ~crc64Fixture()
+    {
+        // resources cleanup, no exceptions allowed
+    }
+
+    // shared user data
+};
+
+TEST_F(crc64Fixture, crc64_auto)
+{
+    void*    ctx = crc64_init_ecma();
+    uint64_t crc;
+
+    EXPECT_NE(ctx, nullptr);
+
+    crc64_update(ctx, buffer, 1048576);
+    crc = crc64_final(ctx);
+
+    EXPECT_EQ(crc, EXPECTED_CRC64);
+}
+
+TEST_F(crc64Fixture, crc64_auto_misaligned)
+{
+    void*    ctx = crc64_init_ecma();
+    uint64_t crc;
+
+    EXPECT_NE(ctx, nullptr);
+
+    crc64_update(ctx, buffer_misaligned + 1, 1048576);
+    crc = crc64_final(ctx);
+
+    EXPECT_EQ(crc, EXPECTED_CRC64);
+}
+
+TEST_F(crc64Fixture, crc64_auto_15bytes)
+{
+    void*    ctx = crc64_init_ecma();
+    uint64_t crc;
+
+    EXPECT_NE(ctx, nullptr);
+
+    crc64_update(ctx, buffer, 15);
+    crc = crc64_final(ctx);
+
+    EXPECT_EQ(crc, EXPECTED_CRC64_15BYTES);
+}
+
+TEST_F(crc64Fixture, crc64_auto_31bytes)
+{
+    void*    ctx = crc64_init_ecma();
+    uint64_t crc;
+
+    EXPECT_NE(ctx, nullptr);
+
+    crc64_update(ctx, buffer, 31);
+    crc = crc64_final(ctx);
+
+    EXPECT_EQ(crc, EXPECTED_CRC64_31BYTES);
+}
+
+TEST_F(crc64Fixture, crc64_auto_63bytes)
+{
+    void*    ctx = crc64_init_ecma();
+    uint64_t crc;
+
+    EXPECT_NE(ctx, nullptr);
+
+    crc64_update(ctx, buffer, 63);
+    crc = crc64_final(ctx);
+
+    EXPECT_EQ(crc, EXPECTED_CRC64_63BYTES);
+}
+
+TEST_F(crc64Fixture, crc64_auto_2352bytes)
+{
+    void*    ctx = crc64_init_ecma();
+    uint64_t crc;
+
+    EXPECT_NE(ctx, nullptr);
+
+    crc64_update(ctx, buffer, 2352);
+    crc = crc64_final(ctx);
+
+    EXPECT_EQ(crc, EXPECTED_CRC64_2352BYTES);
+}
\ No newline at end of file
diff --git a/tests/data/random b/tests/data/random
new file mode 100644
index 0000000..466b7fa
Binary files /dev/null and b/tests/data/random differ
diff --git a/tests/lib b/tests/lib
new file mode 160000
index 0000000..9d21db9
--- /dev/null
+++ b/tests/lib
@@ -0,0 +1 @@
+Subproject commit 9d21db9e0a60a1ea61ec19331c9bc0dd33e907b1