diff --git a/src/cli/src/main.rs b/src/cli/src/main.rs
index f39b6e8..f53f6eb 100644
--- a/src/cli/src/main.rs
+++ b/src/cli/src/main.rs
@@ -1,7 +1,7 @@
 extern crate klotski_ffi;
 
 fn main() {
-    // println!("{:#?}", klotski_ffi::load_metadata());
+    println!("{:#?}", klotski_ffi::metadata());
 
     // println!("{}", klotski_ffi::is_short_code_available());
     // println!("{}", klotski_ffi::is_short_code_available_fast());
diff --git a/src/rust_ffi/src/codec/ffi.rs b/src/rust_ffi/src/codec/ffi.rs
index fdb634f..4a99a26 100644
--- a/src/rust_ffi/src/codec/ffi.rs
+++ b/src/rust_ffi/src/codec/ffi.rs
@@ -1,43 +1,50 @@
-use std::ffi::{c_char, CString};
 use super::Core;
+use std::ffi::{c_char, CString};
 
-fn short_code_enable() {
+#[allow(dead_code)]
+pub fn short_code_enable() {
     unsafe {
         Core::short_code_enable()
     }
 }
 
-fn short_code_enable_fast() {
+#[allow(dead_code)]
+pub fn short_code_enable_fast() {
     unsafe {
         Core::short_code_enable_fast()
     }
 }
 
-fn is_short_code_available() -> bool {
+#[allow(dead_code)]
+pub fn is_short_code_available() -> bool {
     unsafe {
         Core::is_short_code_available()
     }
 }
 
-fn is_short_code_available_fast() -> bool {
+#[allow(dead_code)]
+pub fn is_short_code_available_fast() -> bool {
     unsafe {
         Core::is_short_code_available_fast()
     }
 }
 
-fn raw_code_check(raw_code: u64) -> bool {
+#[allow(dead_code)]
+pub fn raw_code_check(raw_code: u64) -> bool {
     unsafe {
         Core::raw_code_check(raw_code)
     }
 }
 
-fn short_code_check(short_code: u32) -> bool {
+#[allow(dead_code)]
+pub fn short_code_check(short_code: u32) -> bool {
     unsafe {
         Core::short_code_check(short_code)
     }
 }
 
-fn common_code_check(common_code: u64) -> bool {
+#[allow(dead_code)]
+pub fn common_code_check(common_code: u64) -> bool {
     unsafe {
         Core::common_code_check(common_code)
     }
diff --git a/src/rust_ffi/src/codec/mod.rs b/src/rust_ffi/src/codec/mod.rs
index 8b84988..b92c889 100644
--- a/src/rust_ffi/src/codec/mod.rs
+++ b/src/rust_ffi/src/codec/mod.rs
@@ -1,3 +1,4 @@
-pub mod ffi;
+mod ffi;
+mod tests;
 
 use super::core::Core;
diff --git a/src/rust_ffi/src/codec/tests.rs b/src/rust_ffi/src/codec/tests.rs
new file mode 100644
index 0000000..baa00b8
--- /dev/null
+++ b/src/rust_ffi/src/codec/tests.rs
@@ -0,0 +1,71 @@
+mod ffi {
+    #[allow(unused_imports)]
+    use crate::codec::ffi as codec_ffi;
+
+    #[test]
+    fn warm_up() {
+        assert_eq!(codec_ffi::is_short_code_available(), false);
+        codec_ffi::short_code_enable();
+        assert_eq!(codec_ffi::is_short_code_available(), true);
+
+        assert_eq!(codec_ffi::is_short_code_available_fast(), false);
+        codec_ffi::short_code_enable_fast();
+        assert_eq!(codec_ffi::is_short_code_available_fast(), true);
+    }
+
+    #[allow(dead_code)]
+    const TEST_SHORT_CODE_OK: u32 = 4091296;
+
+    #[allow(dead_code)]
+    const TEST_SHORT_CODE_STR_OK: &str = "4WVE1";
+
+    #[allow(dead_code)]
+    const TEST_COMMON_CODE_OK: u64 = 0x1_A9BF_0C00;
+
+    #[allow(dead_code)]
+    const TEST_COMMON_CODE_STR_OK: &str = "1A9BF0C00";
+
+    #[allow(dead_code)]
+    const TEST_COMMON_CODE_STR_SHR_OK: &str = "1A9BF0C";
+
+    #[allow(dead_code)]
+    const TEST_RAW_CODE_OK: u64 = 0x0603_EDF5_CAFF_F5E2;
+
+    #[allow(dead_code)]
+    const TEST_SHORT_CODE_ERR: u32 = 29670987;
+
+    #[allow(dead_code)]
+    const TEST_COMMON_CODE_ERR: u64 = 0x1_2190_2300;
+
+    #[allow(dead_code)]
+    const TEST_RAW_CODE_ERR: u64 = 0x0A34_182B_3810_2D21;
+
+    #[allow(dead_code)]
+    const TEST_SHORT_CODE_STR_ERR: &str = "R50EH";
+
+    #[allow(dead_code)]
+    const TEST_COMMON_CODE_STR_ERR: &str = "123J432A9";
+
+    #[test]
+    fn checker() {
+        assert_eq!(codec_ffi::raw_code_check(TEST_RAW_CODE_OK), true);
+        assert_eq!(codec_ffi::raw_code_check(TEST_RAW_CODE_ERR), false);
+
+        assert_eq!(codec_ffi::short_code_check(TEST_SHORT_CODE_OK), true);
+        assert_eq!(codec_ffi::short_code_check(TEST_SHORT_CODE_ERR), false);
+
+        assert_eq!(codec_ffi::common_code_check(TEST_COMMON_CODE_OK), true);
+        assert_eq!(codec_ffi::common_code_check(TEST_COMMON_CODE_ERR), false);
+    }
+
+    // TODO: string
+
+    // TODO: convert
+
+    // TODO: convert_unsafe
+
+    // TODO: mirror
+
+    // TODO: mirror_unsafe
+
+}
diff --git a/src/rust_ffi/src/lib.rs b/src/rust_ffi/src/lib.rs
index 8e9d58a..a8ae7f5 100644
--- a/src/rust_ffi/src/lib.rs
+++ b/src/rust_ffi/src/lib.rs
@@ -2,6 +2,4 @@ mod core;
 mod codec;
 mod metadata;
 
-pub use metadata::load_metadata;
-
-pub use codec::ffi::*;
+pub use metadata::load_metadata as metadata;
diff --git a/src/rust_ffi/src/metadata.rs b/src/rust_ffi/src/metadata.rs
index c94c371..babe469 100644
--- a/src/rust_ffi/src/metadata.rs
+++ b/src/rust_ffi/src/metadata.rs
@@ -1,4 +1,4 @@
-use super::core::Core;
+use crate::core::Core;
 use Core::CStringDump;
 
 #[derive(Debug)]
@@ -35,3 +35,22 @@ pub fn load_metadata() -> Metadata {
         }
     }
 }
+
+#[test]
+fn tests() {
+    let metadata = load_metadata();
+
+    assert_ne!(metadata.author, "");
+    assert_ne!(metadata.system, "");
+    assert_ne!(metadata.git_tag, "");
+    assert_ne!(metadata.version, "");
+    assert_ne!(metadata.compiler, "");
+    assert_ne!(metadata.commit_id, "");
+    assert_ne!(metadata.build_time, "");
+    assert_ne!(metadata.git_branch, "");
+    assert_ne!(metadata.project_url, "");
+
+    assert!(metadata.version_patch < 65536);
+    assert!(metadata.version_minor < 65536);
+    assert!(metadata.version_patch < 65536);
+}
diff --git a/test/ffi/codec.cc b/test/ffi/codec.cc
index c834115..d5cb35c 100644
--- a/test/ffi/codec.cc
+++ b/test/ffi/codec.cc
@@ -151,7 +151,6 @@ TEST(FFI, codec_mirror) {
     bool result;
     uint64_t raw_code;
 
-    /// test of safe version
     EXPECT_EQ(is_vertical_mirror(TEST_RAW_CODE_ERR, &result), false);
     EXPECT_EQ(is_horizontal_mirror(TEST_RAW_CODE_ERR, &result), false);
     EXPECT_EQ(to_vertical_mirror(TEST_RAW_CODE_ERR, &raw_code), false);
@@ -174,8 +173,9 @@ TEST(FFI, codec_mirror) {
     EXPECT_EQ(raw_code, TEST_MIRROR_H2);
     EXPECT_EQ(to_horizontal_mirror(TEST_MIRROR_H2, &raw_code), true);
     EXPECT_EQ(raw_code, TEST_MIRROR_H1);
+}
 
-    /// test of unsafe version
+TEST(FFI, codec_mirror_unsafe) {
     EXPECT_EQ(is_vertical_mirror_unsafe(TEST_MIRROR_V), true);
     EXPECT_EQ(is_vertical_mirror_unsafe(TEST_MIRROR_V1), false);
     EXPECT_EQ(is_vertical_mirror_unsafe(TEST_MIRROR_V2), false);