diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 7891023..a73f3a1 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -11,6 +11,14 @@ add_library(md5 STATIC ../third_party/md5/md5.cpp)
 
 ################################################################
 
+include_directories(../src/klotski/utils)
+add_executable(test_utils utils.cc)
+target_link_libraries(test_utils PUBLIC gtest gtest_main)
+target_link_libraries(test_utils PUBLIC utils)
+add_test(NAME utils COMMAND test_utils)
+
+################################################################
+
 include_directories(../src/klotski/all_cases)
 add_executable(test_all_cases all_cases.cc)
 target_link_libraries(test_all_cases PUBLIC gtest gtest_main)
diff --git a/test/all_cases.cc b/test/all_cases.cc
index 980822f..6802901 100644
--- a/test/all_cases.cc
+++ b/test/all_cases.cc
@@ -6,16 +6,9 @@
 using namespace klotski;
 
 /// basic ranges constants
-//const uint32_t BASIC_RANGES_SIZE = 7311921;
 const char BASIC_RANGES_MD5[] = "6f385dc171e201089ff96bb010b47212";
 
 /// all cases constants
-//const uint32_t ALL_CASES_SIZE[16] = {
-//    2942906, 2260392, 2942906, 0,
-//    2322050, 1876945, 2322050, 0,
-//    2322050, 1876945, 2322050, 0,
-//    2942906, 2260392, 2942906, 0,
-//};
 const uint32_t ALL_CASES_SIZE_SUM = 29334498;
 const char ALL_CASES_MD5[] = "3888e9fab8d3cbb50908b12b147cfb23";
 
diff --git a/test/utils.cc b/test/utils.cc
new file mode 100644
index 0000000..c3edf57
--- /dev/null
+++ b/test/utils.cc
@@ -0,0 +1,36 @@
+#include <cstdint>
+#include "common.h"
+#include "gtest/gtest.h"
+
+using namespace klotski;
+
+TEST(Utils, range_reverse) {
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x00000003), (uint32_t)0xC0000000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x0000000C), (uint32_t)0x30000000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x00000030), (uint32_t)0x0C000000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x000000C0), (uint32_t)0x03000000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x00000300), (uint32_t)0x00C00000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x00000C00), (uint32_t)0x00300000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x00003000), (uint32_t)0x000C0000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x0000C000), (uint32_t)0x00030000);
+
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x0000000F), (uint32_t)0xF0000000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x000000FF), (uint32_t)0xFF000000);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x0000FFFF), (uint32_t)0xFFFF0000);
+
+    EXPECT_EQ(Common::range_reverse((uint32_t)0x55555555), (uint32_t)0x55555555);
+    EXPECT_EQ(Common::range_reverse((uint32_t)0xAAAAAAAA), (uint32_t)0xAAAAAAAA);
+}
+
+TEST(Utils, check_range) {
+    EXPECT_NE(Common::check_range(1, 0xA9BF0C00), 0);
+    EXPECT_EQ(Common::check_range(1, 0x0030FE6A), 0);
+
+    EXPECT_NE(Common::check_range(4, 0xFEA13400), 0);
+    EXPECT_EQ(Common::check_range(4, 0x001C4ABF), 0);
+
+    EXPECT_EQ(Common::check_range(5, 0x004845D3), 5);
+    EXPECT_EQ(Common::check_range(10, 0x003B7521), 8);
+    EXPECT_EQ(Common::check_range(13, 0x000EC9D3), 9);
+    EXPECT_EQ(Common::check_range(15, 0x00A3B724), 6);
+}