diff --git a/flake.nix b/flake.nix
index 4febca24..a6ce5fce 100644
--- a/flake.nix
+++ b/flake.nix
@@ -13,6 +13,7 @@
           ''
           mkdir -p $out/bin
           ln -s ${pkgs.llvmPackages_14.clang-unwrapped}/bin/clang $out/bin/clang-irrt
+          ln -s ${pkgs.llvmPackages_14.clang}/bin/clang $out/bin/clang-irrt-test
           ln -s ${pkgs.llvmPackages_14.llvm.out}/bin/llvm-as $out/bin/llvm-as-irrt
           '';
         nac3artiq = pkgs.python3Packages.toPythonModule (
@@ -23,6 +24,7 @@
             cargoLock = {
               lockFile = ./Cargo.lock;
             };
+            cargoTestFlags = [ "--features" "test" ];
             passthru.cargoLock = cargoLock;
             nativeBuildInputs = [ pkgs.python3 pkgs.llvmPackages_14.clang llvm-tools-irrt pkgs.llvmPackages_14.llvm.out llvm-nac3 ];
             buildInputs = [ pkgs.python3 llvm-nac3 ];
diff --git a/nac3core/Cargo.toml b/nac3core/Cargo.toml
index 724e0c8c..6e66f440 100644
--- a/nac3core/Cargo.toml
+++ b/nac3core/Cargo.toml
@@ -1,3 +1,6 @@
+[features]
+test = []
+
 [package]
 name = "nac3core"
 version = "0.1.0"
diff --git a/nac3core/build.rs b/nac3core/build.rs
index 9d6292a2..7f4e0454 100644
--- a/nac3core/build.rs
+++ b/nac3core/build.rs
@@ -3,22 +3,32 @@ use std::{
     env,
     fs::File,
     io::Write,
-    path::Path,
+    path::{Path, PathBuf},
     process::{Command, Stdio},
 };
 
-fn main() {
-    // Define relevant directories
-    let out_dir = env::var("OUT_DIR").unwrap();
-    let out_dir = Path::new(&out_dir);
-    let irrt_dir = Path::new("irrt");
+const CMD_IRRT_CLANG: &str = "clang-irrt";
+const CMD_IRRT_CLANG_TEST: &str = "clang-irrt-test";
+const CMD_IRRT_LLVM_AS: &str = "llvm-as-irrt";
 
-    let irrt_cpp_path = irrt_dir.join("irrt.cpp");
+fn get_out_dir() -> PathBuf {
+    PathBuf::from(env::var("OUT_DIR").unwrap())
+}
+
+fn get_irrt_dir() -> &'static Path {
+    Path::new("irrt")
+}
+
+/// Compile `irrt.cpp` for use in `src/codegen`
+fn compile_irrt_cpp() {
+    let out_dir = get_out_dir();
+    let irrt_dir = get_irrt_dir();
 
     /*
      * HACK: Sadly, clang doesn't let us emit generic LLVM bitcode.
      * Compiling for WASM32 and filtering the output with regex is the closest we can get.
      */
+    let irrt_cpp_path = irrt_dir.join("irrt.cpp");
     let flags: &[&str] = &[
         "--target=wasm32",
         "-x",
@@ -45,7 +55,7 @@ fn main() {
     println!("cargo:rerun-if-changed={}", irrt_dir.to_str().unwrap());
 
     // Compile IRRT and capture the LLVM IR output
-    let output = Command::new("clang-irrt")
+    let output = Command::new(CMD_IRRT_CLANG)
         .args(flags)
         .output()
         .map(|o| {
@@ -88,7 +98,7 @@ fn main() {
 
     // Assemble the emitted and filtered IR to .bc
     // That .bc will be integrated into nac3core's codegen
-    let mut llvm_as = Command::new("llvm-as-irrt")
+    let mut llvm_as = Command::new(CMD_IRRT_LLVM_AS)
         .stdin(Stdio::piped())
         .arg("-o")
         .arg(out_dir.join("irrt.bc"))
@@ -97,3 +107,48 @@ fn main() {
     llvm_as.stdin.as_mut().unwrap().write_all(filtered_output.as_bytes()).unwrap();
     assert!(llvm_as.wait().unwrap().success());
 }
+
+/// Compile `irrt_test.cpp` for testing
+fn compile_irrt_test_cpp() {
+    let out_dir = get_out_dir();
+    let irrt_dir = get_irrt_dir();
+
+    let exe_path = out_dir.join("irrt_test.out"); // Output path of the compiled test executable
+    let irrt_test_cpp_path = irrt_dir.join("irrt_test.cpp");
+    let flags: &[&str] = &[
+        irrt_test_cpp_path.to_str().unwrap(),
+        "-x",
+        "c++",
+        "-I",
+        irrt_dir.to_str().unwrap(),
+        "-g",
+        "-fno-discard-value-names",
+        "-O0",
+        "-Wall",
+        "-Wextra",
+        "-Werror=return-type",
+        "-lm", // for `tgamma()`, `lgamma()`
+        "-o",
+        exe_path.to_str().unwrap(),
+    ];
+
+    Command::new(CMD_IRRT_CLANG_TEST)
+        .args(flags)
+        .output()
+        .map(|o| {
+            assert!(o.status.success(), "{}", std::str::from_utf8(&o.stderr).unwrap());
+            o
+        })
+        .unwrap();
+    println!("cargo:rerun-if-changed={}", irrt_dir.to_str().unwrap());
+}
+
+fn main() {
+    compile_irrt_cpp();
+
+    // https://github.com/rust-lang/cargo/issues/2549
+    // `cargo test -F test` to also build `irrt_test.cpp
+    if cfg!(feature = "test") {
+        compile_irrt_test_cpp();
+    }
+}
diff --git a/nac3core/irrt/irrt.cpp b/nac3core/irrt/irrt.cpp
index 4aa710c8..489ce090 100644
--- a/nac3core/irrt/irrt.cpp
+++ b/nac3core/irrt/irrt.cpp
@@ -1,3 +1,4 @@
+#define IRRT_DEFINE_TYPEDEF_INTS
 #include "irrt_everything.hpp"
 
 /*
diff --git a/nac3core/irrt/irrt/int_defs.hpp b/nac3core/irrt/irrt/int_defs.hpp
index c24f7394..a610ea9c 100644
--- a/nac3core/irrt/irrt/int_defs.hpp
+++ b/nac3core/irrt/irrt/int_defs.hpp
@@ -1,8 +1,12 @@
 #pragma once
 
-using int8_t = _BitInt(8);
-using uint8_t = unsigned _BitInt(8);
-using int32_t = _BitInt(32);
-using uint32_t = unsigned _BitInt(32);
-using int64_t = _BitInt(64);
-using uint64_t = unsigned _BitInt(64);
\ No newline at end of file
+// This is made toggleable since `irrt_test.cpp` itself would include
+// headers that define these typedefs
+#ifdef IRRT_DEFINE_TYPEDEF_INTS
+typedef _BitInt(8) int8_t;
+typedef unsigned _BitInt(8) uint8_t;
+typedef _BitInt(32) int32_t;
+typedef unsigned _BitInt(32) uint32_t;
+typedef _BitInt(64) int64_t;
+typedef unsigned _BitInt(64) uint64_t;
+#endif
\ No newline at end of file
diff --git a/nac3core/irrt/irrt/utils.hpp b/nac3core/irrt/irrt/utils.hpp
index 728d5f81..6735f36b 100644
--- a/nac3core/irrt/irrt/utils.hpp
+++ b/nac3core/irrt/irrt/utils.hpp
@@ -10,4 +10,12 @@ template <typename T>
 const T& min(const T& a, const T& b) {
     return a > b ? b : a;
 }
+
+template <typename T>
+bool arrays_match(int len, T* as, T* bs) {
+    for (int i = 0; i < len; i++) {
+        if (as[i] != bs[i]) return false;
+    }
+    return true;
 }
+}
\ No newline at end of file
diff --git a/nac3core/irrt/irrt_test.cpp b/nac3core/irrt/irrt_test.cpp
new file mode 100644
index 00000000..8aa64c2f
--- /dev/null
+++ b/nac3core/irrt/irrt_test.cpp
@@ -0,0 +1,16 @@
+// This file will be compiled like a real C++ program,
+// and we do have the luxury to use the standard libraries.
+// That is if the nix flakes do not have issues... especially on msys2...
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+#include "irrt_everything.hpp"
+
+#include "test/core.hpp"
+#include "test/test_core.hpp"
+
+int main() {
+    test_int_exp();
+    return 0;
+}
\ No newline at end of file
diff --git a/nac3core/irrt/test/core.hpp b/nac3core/irrt/test/core.hpp
new file mode 100644
index 00000000..34063aa4
--- /dev/null
+++ b/nac3core/irrt/test/core.hpp
@@ -0,0 +1,88 @@
+#pragma once
+
+// Include this header for every test_*.cpp
+
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+#include "print.hpp"
+
+// Some utils can be used here
+#include "../irrt/utils.hpp"
+
+void __begin_test(const char* function_name, const char* file, int line) {
+    printf("######### Running %s @ %s:%d\n", function_name, file, line);
+}
+
+#define BEGIN_TEST() __begin_test(__FUNCTION__, __FILE__, __LINE__)
+
+void test_fail() {
+    printf("[!] Test failed. Exiting with status code 1.\n");
+    exit(1);
+}
+
+template <typename T>
+void debug_print_array(int len, const T* as) {
+    printf("[");
+    for (int i = 0; i < len; i++) {
+        if (i != 0) printf(", ");
+        print_value(as[i]);
+    }
+    printf("]");
+}
+
+void print_assertion_passed(const char* file, int line) {
+    printf("[*] Assertion passed on %s:%d\n", file, line);
+}
+
+void print_assertion_failed(const char* file, int line) {
+    printf("[!] Assertion failed on %s:%d\n", file, line);
+}
+
+void __assert_true(const char* file, int line, bool cond) {
+    if (cond) {
+        print_assertion_passed(file, line);
+    } else {
+        print_assertion_failed(file, line);
+        test_fail();
+    }
+}
+
+#define assert_true(cond) __assert_true(__FILE__, __LINE__, cond)
+
+template <typename T>
+void __assert_arrays_match(const char* file, int line, int len, const T* expected, const T* got) {
+    if (arrays_match(len, expected, got)) {
+        print_assertion_passed(file, line);
+    } else {
+        print_assertion_failed(file, line);
+        printf("Expect = ");
+        debug_print_array(len, expected);
+        printf("\n");
+        printf("   Got = ");
+        debug_print_array(len, got);
+        printf("\n");
+        test_fail();
+    }
+}
+
+#define assert_arrays_match(len, expected, got) __assert_arrays_match(__FILE__, __LINE__, len, expected, got)
+
+template <typename T>
+void __assert_values_match(const char* file, int line, T expected, T got) {
+    if (expected == got) {
+        print_assertion_passed(file, line);
+    } else {
+        print_assertion_failed(file, line);
+        printf("Expect = ");
+        print_value(expected);
+        printf("\n");
+        printf("   Got = ");
+        print_value(got);
+        printf("\n");
+        test_fail();
+    }
+}
+
+#define assert_values_match(expected, got) __assert_values_match(__FILE__, __LINE__, expected, got)
\ No newline at end of file
diff --git a/nac3core/irrt/test/print.hpp b/nac3core/irrt/test/print.hpp
new file mode 100644
index 00000000..bd0ec746
--- /dev/null
+++ b/nac3core/irrt/test/print.hpp
@@ -0,0 +1,42 @@
+#pragma once
+
+#include <cstdlib>
+#include <cstdio>
+
+template <class T>
+void print_value(const T& value) {}
+
+template <>
+void print_value(const int8_t& value) {
+    printf("%d", value);
+}
+
+template <>
+void print_value(const int32_t& value) {
+    printf("%d", value);
+}
+
+template <>
+void print_value(const uint8_t& value) {
+    printf("%u", value);
+}
+
+template <>
+void print_value(const uint32_t& value) {
+    printf("%u", value);
+}
+
+template <>
+void print_value(const double& value) {
+    printf("%f", value);
+}
+
+// template <double>
+// void print_value(const double& value) {
+//     printf("%f", value);
+// }
+// 
+// template <char *>
+// void print_value(const char*& value) {
+//     printf("%f", value);
+// }
\ No newline at end of file
diff --git a/nac3core/irrt/test/test_core.hpp b/nac3core/irrt/test/test_core.hpp
new file mode 100644
index 00000000..ec2a5493
--- /dev/null
+++ b/nac3core/irrt/test/test_core.hpp
@@ -0,0 +1,11 @@
+#pragma once
+
+#include "core.hpp"
+#include "../irrt/core.hpp"
+
+void test_int_exp() {
+    BEGIN_TEST();
+
+    assert_values_match(125, __nac3_int_exp_impl<int32_t>(5, 3));
+    assert_values_match(3125, __nac3_int_exp_impl<int32_t>(5, 5));
+}
\ No newline at end of file
diff --git a/nac3core/src/codegen/irrt/mod.rs b/nac3core/src/codegen/irrt/mod.rs
index 755bcf57..dfb91611 100644
--- a/nac3core/src/codegen/irrt/mod.rs
+++ b/nac3core/src/codegen/irrt/mod.rs
@@ -1,5 +1,7 @@
 use crate::typecheck::typedef::Type;
 
+mod test;
+
 use super::{
     classes::{
         ArrayLikeIndexer, ArrayLikeValue, ArraySliceValue, ListValue, NDArrayValue,
diff --git a/nac3core/src/codegen/irrt/test.rs b/nac3core/src/codegen/irrt/test.rs
new file mode 100644
index 00000000..9a91f41f
--- /dev/null
+++ b/nac3core/src/codegen/irrt/test.rs
@@ -0,0 +1,26 @@
+#[cfg(test)]
+mod tests {
+    use std::{path::Path, process::Command};
+
+    #[test]
+    fn run_irrt_test() {
+        assert!(
+            cfg!(feature = "test"),
+            "Please do `cargo test -F test` to compile `irrt_test.out` and run test"
+        );
+
+        let irrt_test_out_path = Path::new(concat!(env!("OUT_DIR"), "/irrt_test.out"));
+        let output = Command::new(irrt_test_out_path.to_str().unwrap()).output().unwrap();
+
+        if !output.status.success() {
+            eprintln!("irrt_test failed with status {}:", output.status);
+            eprintln!("====== stdout ======");
+            eprintln!("{}", String::from_utf8(output.stdout).unwrap());
+            eprintln!("====== stderr ======");
+            eprintln!("{}", String::from_utf8(output.stderr).unwrap());
+            eprintln!("====================");
+
+            panic!("irrt_test failed");
+        }
+    }
+}