diff --git a/tests/fuzz.py b/tests/fuzz.py
index 8d46b1c..7f9bfe4 100644
--- a/tests/fuzz.py
+++ b/tests/fuzz.py
@@ -9,9 +9,7 @@ below `REPLACE_DICT`.
 
 import os
 import subprocess
-import itertools
 import argparse
-import sys
 import re
 import random
 from pathlib import Path
@@ -26,40 +24,47 @@ REPLACE_DICT = {
     r"__attribute__\s*\(\(.*\)\)": "",
     "_Float128": "double",
     "long double": "double",
-    "(\+[0-9^FL]*)L": r"\1",
+    r"(\+[0-9^FL]*)L": r"\1",
     "union": "struct",
     r"enum[\w\s]*\{[^\}]*\};": "",
     r"typedef enum[\w\s]*\{[^;]*;[\s_A-Z]*;": "",
-    "const char \*const sys_errlist\[\];": "",      # ArraySize::Unknown 삭제
+    r"const char \*const sys_errlist\[\];": "",  # ArraySize::Unknown 삭제
     r"[^\n]*printf[^;]*;": "",
     r"[^\n]*scanf[^;]*;": "",
     " restrict": "",
     "inline ": "",
     "_Nullable": "",
-    "\"g_\w*\", ": "",              # transparent_crc에서 프린트 목적으로 받은 StringLiteral 삭제
-    "char\* vname, ": "",           # transparent_crc에서 사용하지 않는 파라미터 삭제
-    r"transparent_crc_bytes\s*\([^;]*\);": "", # transparent_crc_bytes 삭제
-    r"[^\n]*_IO_2_1_[^;]*;": "",    # extern을 지우면서 생긴 size를 알 수 없는 struct 삭제
-    r"__asm\s*\([^\)]*\)": "",      # asm extension in mac
-    r"__asm__\s*\([^\)]*\)": "",    # asm extension in linux
+    r'"g_\w*", ': "",  # transparent_crc에서 프린트 목적으로 받은 StringLiteral 삭제
+    r"char\* vname, ": "",  # transparent_crc에서 사용하지 않는 파라미터 삭제
+    r"transparent_crc_bytes\s*\([^;]*\);": "",  # transparent_crc_bytes 삭제
+    r"[^\n]*_IO_2_1_[^;]*;": "",  # extern을 지우면서 생긴 size를 알 수 없는 struct 삭제
+    r"__asm\s*\([^\)]*\)": "",  # asm extension in mac
+    r"__asm__\s*\([^\)]*\)": "",  # asm extension in linux
     "typedef __builtin_va_list __gnuc_va_list;": "",
     "typedef __gnuc_va_list va_list;": "",
     r"\(fabsf\(": "((",
-    
     # todo: need to consider the case below in the future:
     # avoid compile-time constant expressed as complex expression such as `1 + 1`
-    "char _unused2[^;]*;": "char _unused2[10];", 
+    "char _unused2[^;]*;": "char _unused2[10];",
 }
 CSMITH_DIR = "csmith-2.3.0"
 SKIP_TEST = 102
 
+
 class ProgressBar:
     def __init__(self):
         self.stage = 0
-        self.stage_indicators = ["-", "\\", "|", "/", ]
-        self.pbar = tqdm.tqdm(total=1, bar_format="{l_bar}{bar}| [Elapsed:{elapsed}, <ETA:{remaining}]")
+        self.stage_indicators = [
+            "-",
+            "\\",
+            "|",
+            "/",
+        ]
+        self.pbar = tqdm.tqdm(
+            total=1, bar_format="{l_bar}{bar}| [Elapsed:{elapsed}, <ETA:{remaining}]"
+        )
         self.last_progress = 0
-    
+
     def print_progressbar(self, progress):
         indicator = self.stage_indicators[self.stage % len(self.stage_indicators)]
         self.stage += 1
@@ -67,50 +72,57 @@ class ProgressBar:
         self.pbar.update(progress - self.last_progress)
         self.last_progress = progress
 
-def install_csmith(tests_dir):
-    global CSMITH_DIR
 
-    usr_bin_path = "/usr/bin/csmith"
-    usr_inc_path = "/usr/include/csmith"
+def execute_command(command, cwd=None):
+    try:
+        process = subprocess.Popen(
+            command, shell=True, cwd=cwd, stdout=subprocess.PIPE, stderr=subprocess.PIPE
+        )
+        stdout, stderr = process.communicate()
+
+        if process.returncode != 0:
+            raise subprocess.CalledProcessError(
+                process.returncode, command, stderr.decode("utf-8")
+            )
+        print(stdout.decode("utf-8"))
+        return True
+    except subprocess.CalledProcessError as e:
+        print(f"Error executing command: {e.cmd}")
+        print(e.output)
+        return False
+    except Exception as e:
+        print(f"Unexpected error: {str(e)}")
+        return False
+
+
+def install_csmith():
+    """
+    Installation based on the provided in the github repos
+    of the package. Make sure to have sudo privileges.
+    """
+    usr_bin_path = "/usr/local/bin/csmith"
+    usr_inc_path = "/usr/local/include/"  # cmake dumps the include files here.
     if os.path.exists(usr_bin_path):
-        assert os.path.exists(usr_inc_path)
         return usr_bin_path, usr_inc_path
 
-    bin_path = os.path.abspath(os.path.join(tests_dir, CSMITH_DIR, "src/csmith"))
-    inc_path = os.path.abspath(os.path.join(tests_dir, CSMITH_DIR, "runtime"))
-    if not os.path.exists(bin_path):
-        csmith_filename = "{}.tar.gz".format(CSMITH_DIR)
-        try:
-            args = ["curl", "https://embed.cs.utah.edu/csmith/{}".format(csmith_filename), "-o", csmith_filename]
-            proc = subprocess.Popen(args, cwd=tests_dir)
-            proc.communicate()
-            if proc.returncode != 0:
-                raise Exception("Failed to download Csmith (exit code: {}): `{}`".format(proc.returncode, " ".join(args)))
-        except subprocess.TimeoutExpired as e:
-            proc.kill()
-            raise e
+    csmith_dir = os.path.join(os.getcwd(), "csmith")
+    if not os.path.exists(csmith_dir):
+        if not execute_command(
+            "git clone https://github.com/csmith-project/csmith.git"
+        ):
+            raise Exception("Unable to clone the Csmith repository")
 
-        try:
-            args = ["tar", "xzvf", csmith_filename]
-            proc = subprocess.Popen(args, cwd=tests_dir)
-            proc.communicate()
-            if proc.returncode != 0:
-                raise Exception("Failed to extract Csmith (exit code: {}): `{}`".format(proc.returncode, " ".join(args)))
-        except subprocess.TimeoutExpired as e:
-            proc.kill()
-            raise e
+    if not execute_command("sudo apt install -y g++ cmake m4", cwd=csmith_dir):
+        raise Exception("Unable to install dependencies")
 
-        csmith_root_dir = os.path.join(tests_dir, CSMITH_DIR)
-        try:
-            proc = subprocess.Popen("cmake . && make -j", shell=True, cwd=csmith_root_dir)
-            proc.communicate()
-            if proc.returncode != 0:
-                raise Exception("Failed to build Csmith (exit code: {})".format(proc.returncode))
-        except subprocess.TimeoutExpired as e:
-            proc.kill()
-            raise e
+    cmake_command = f"cmake -DCMAKE_INSTALL_PREFIX=/usr/local/ ."
+    if not execute_command(cmake_command, cwd=csmith_dir):
+        raise Exception("Unable to run cmake.")
+
+    if not execute_command("make && sudo make install", cwd=csmith_dir):
+        raise Exception("Unable to install.")
+    return usr_bin_path, usr_inc_path
 
-    return bin_path, inc_path
 
 def generate(tests_dir, bin_path, seed, easy):
     """Feeding options to built Csmith to randomly generate test case.
@@ -122,17 +134,25 @@ def generate(tests_dir, bin_path, seed, easy):
     """
     global CSMITH_DIR
     options = [
-        "--no-argc", "--no-arrays",
-        "--no-jumps", "--no-pointers",
-        "--no-structs", "--no-unions",
-        "--float", "--strict-float",
-        "--seed", str(seed),
+        "--no-argc",
+        "--no-arrays",
+        "--no-jumps",
+        "--no-pointers",
+        "--no-structs",
+        "--no-unions",
+        "--float",
+        "--strict-float",
+        "--seed",
+        str(seed),
     ]
     if easy:
         options += [
-            "--max-block-depth", "2",
-            "--max-block-size", "2",
-            "--max-struct-fields", "3",
+            "--max-block-depth",
+            "2",
+            "--max-block-size",
+            "2",
+            "--max-struct-fields",
+            "3",
         ]
     args = [bin_path] + options
 
@@ -144,17 +164,19 @@ def generate(tests_dir, bin_path, seed, easy):
         proc.kill()
         raise e
 
+
 def polish(src, inc_path):
-    """Polishing test case to fit in kecc parser specification.
-    """
+    """Polishing test case to fit in kecc parser specification."""
     global REPLACE_DICT, CSMITH_DIR
 
     try:
-        args = ["gcc",
-                "-I", inc_path,
-                "-E",
-                "-P",
-                "-",
+        args = [
+            "gcc",
+            "-I",
+            inc_path,
+            "-E",
+            "-P",
+            "-",
         ]
         proc = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
         (src_preprocessed, err) = proc.communicate(src.encode())
@@ -169,15 +191,19 @@ def polish(src, inc_path):
 
     return src_replaced
 
+
 def make_reduce_criteria(tests_dir, fuzz_arg, fuzz_errmsg, analyze):
-    """Make executable reduce-criteria.sh
-    """
+    """Make executable reduce-criteria.sh"""
     # Make shell script i.e. dependent to KECC path
     arg_dict = {
         "$PROJECT_DIR": str(Path(tests_dir).parent),
         "$FUZZ_ARG": fuzz_arg,
-        "$KECC_BIN": str(os.path.abspath(os.path.join(tests_dir, "../target/release/kecc"))),
-        "$FUZZ_BIN": str(os.path.abspath(os.path.join(tests_dir, "../target/release/fuzz"))),
+        "$KECC_BIN": str(
+            os.path.abspath(os.path.join(tests_dir, "../target/release/kecc"))
+        ),
+        "$FUZZ_BIN": str(
+            os.path.abspath(os.path.join(tests_dir, "../target/release/fuzz"))
+        ),
         "$FUZZ_ERRMSG": "'{}'".format(fuzz_errmsg),
         "$CLANG_ANALYZE": str(analyze).lower(),
     }
@@ -191,33 +217,51 @@ def make_reduce_criteria(tests_dir, fuzz_arg, fuzz_errmsg, analyze):
     # chmod the script executable
     try:
         args = ["chmod", "u+x", "reduce-criteria.sh"]
-        proc = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir)
+        proc = subprocess.Popen(
+            args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir
+        )
         proc.communicate()
         if proc.returncode != 0:
-            raise Exception("`{}` failed with exit code {}.".format(" ".join(args), proc.returncode))
+            raise Exception(
+                "`{}` failed with exit code {}.".format(" ".join(args), proc.returncode)
+            )
     except subprocess.TimeoutExpired as e:
         proc.kill()
         raise e
 
+
 def make_fuzz_errmsg(tests_dir, fuzz_arg):
-    """Make fuzz error message in reduce-criteria.sh.
-    """
+    """Make fuzz error message in reduce-criteria.sh."""
     fuzz_errmsg = "panicked"
     try:
-        args = ["cargo", "run", "--features=build-bin", "--bin", "fuzz", "--", fuzz_arg, "test_polished.c"]
-        proc = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir)
+        args = [
+            "cargo",
+            "run",
+            "--features=build-bin",
+            "--bin",
+            "fuzz",
+            "--",
+            fuzz_arg,
+            "test_polished.c",
+        ]
+        proc = subprocess.Popen(
+            args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir
+        )
         (out, err) = proc.communicate()
         if proc.returncode != 0:
             if "assertion failed" in out.decode():
                 fuzz_errmsg = "assertion failed"
         else:
-            raise Exception("Reducing failed because `{}` returned 0".format(" ".join(args)))
+            raise Exception(
+                "Reducing failed because `{}` returned 0".format(" ".join(args))
+            )
     except subprocess.TimeoutExpired as e:
         proc.kill()
         raise e
 
     return fuzz_errmsg
 
+
 def creduce(tests_dir, fuzz_arg, analyze):
     """Reduce `tests/test_polished.c` to `tests/test_reduced.c`
 
@@ -230,18 +274,32 @@ def creduce(tests_dir, fuzz_arg, analyze):
 
     try:
         args = ["cp", "test_polished.c", "test_reduced.c"]
-        proc = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir)
+        proc = subprocess.Popen(
+            args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir
+        )
         proc.communicate()
         if proc.returncode != 0:
-            raise Exception("`{}` failed with exit code {}.".format(" ".join(args), proc.returncode))
+            raise Exception(
+                "`{}` failed with exit code {}.".format(" ".join(args), proc.returncode)
+            )
     except subprocess.TimeoutExpired as e:
         proc.kill()
         raise e
 
     try:
         # --tidy: Do not make a backup copy of each file to reduce as file.orig
-        args = ["creduce", "--tidy", "--timing", "--timeout", "20", "./reduce-criteria.sh", "test_reduced.c"]
-        proc = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir)
+        args = [
+            "creduce",
+            "--tidy",
+            "--timing",
+            "--timeout",
+            "20",
+            "./reduce-criteria.sh",
+            "test_reduced.c",
+        ]
+        proc = subprocess.Popen(
+            args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir
+        )
         pbar = ProgressBar()
         while True:
             line = proc.stdout.readline()
@@ -250,26 +308,33 @@ def creduce(tests_dir, fuzz_arg, analyze):
             line = line.decode()
             if "%" in line:
                 try:
-                    pbar.print_progressbar(abs(float(line[1:line.index("%")])) / 100)
+                    pbar.print_progressbar(abs(float(line[1 : line.index("%")])) / 100)
                 except:
-                    pass # This is for potential error
+                    pass  # This is for potential error
         (out, err) = proc.communicate()
         if proc.returncode != 0:
             print(out.decode())
-            raise Exception("Reducing test_reduced.c by `{}` failed with exit code {}.".format(" ".join(args), proc.returncode))
+            raise Exception(
+                "Reducing test_reduced.c by `{}` failed with exit code {}.".format(
+                    " ".join(args), proc.returncode
+                )
+            )
         print("Reduce finished.")
     except subprocess.TimeoutExpired as e:
         proc.kill()
         raise e
 
+
 def fuzz(tests_dir, fuzz_arg, num_iter, easy):
     global SKIP_TEST
 
-    csmith_bin, csmith_inc = install_csmith(tests_dir)
+    csmith_bin, csmith_inc = install_csmith()
     fuzz_bin = os.path.abspath(os.path.join(tests_dir, "../target/release/fuzz"))
     try:
         if num_iter is None:
-            print("Fuzzing with infinitely many test cases.  Please press [ctrl+C] to break.")
+            print(
+                "Fuzzing with infinitely many test cases.  Please press [ctrl+C] to break."
+            )
         else:
             assert num_iter > 0
             print("Fuzzing with {} test cases.".format(num_iter))
@@ -279,16 +344,21 @@ def fuzz(tests_dir, fuzz_arg, num_iter, easy):
         while True:
             print("Test case #{} (skipped: {})".format(i, skip))
             src = generate(tests_dir, csmith_bin, random.randint(1, 987654321), easy)
-            with open(os.path.join(tests_dir, "test.c"), 'w') as dst:
+            with open(os.path.join(tests_dir, "test.c"), "w") as dst:
                 dst.write(src)
 
             src_polished = polish(src, csmith_inc)
-            with open(os.path.join(tests_dir, "test_polished.c"), 'w') as dst:
+            with open(os.path.join(tests_dir, "test_polished.c"), "w") as dst:
                 dst.write(src_polished)
 
             try:
                 args = [fuzz_bin, fuzz_arg, os.path.join(tests_dir, "test_polished.c")]
-                proc = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=tests_dir)
+                proc = subprocess.Popen(
+                    args,
+                    stdout=subprocess.PIPE,
+                    stderr=subprocess.STDOUT,
+                    cwd=tests_dir,
+                )
                 proc.communicate(timeout=60)
 
                 # KECC sets an exit code of 102 when the test skipped.
@@ -296,11 +366,16 @@ def fuzz(tests_dir, fuzz_arg, num_iter, easy):
                     skip += 1
                     continue
                 elif proc.returncode != 0:
-                    raise Exception("Test `{}` failed with exit code {}.".format(" ".join(args), proc.returncode))
+                    raise Exception(
+                        "Test `{}` failed with exit code {}.".format(
+                            " ".join(args), proc.returncode
+                        )
+                    )
 
                 i += 1
                 if num_iter is not None:
-                    if i > num_iter: break
+                    if i > num_iter:
+                        break
             except subprocess.TimeoutExpired as e:
                 proc.kill()
                 skip += 1
@@ -308,21 +383,38 @@ def fuzz(tests_dir, fuzz_arg, num_iter, easy):
         proc.terminate()
         print("\n[Ctrl+C] interrupted")
 
+
 if __name__ == "__main__":
-    parser = argparse.ArgumentParser(description='Fuzzing KECC.')
-    parser.add_argument('-n', '--num', type=int, help='The number of tests')
-    parser.add_argument('-p', '--print', action='store_true', help='Fuzzing C AST printer')
-    parser.add_argument('-i', '--irgen', action='store_true', help='Fuzzing irgen')
-    parser.add_argument('-r', '--reduce', action='store_true', help="Reducing input file")
-    parser.add_argument('--skip-build', action='store_true', help="Skipping cargo build")
-    parser.add_argument('--easy', action='store_true', help="Generate more easy code by csmith option")
-    parser.add_argument('--seed', type=int, help="Provide seed of fuzz generation", default=-1)
-    parser.add_argument('--clang-analyze', action='store_true', help="Use clang static analyzer for reducing. It prevents undefined behaviors coming from reduced program, but perhaps take a long time to do so")
+    parser = argparse.ArgumentParser(description="Fuzzing KECC.")
+    parser.add_argument("-n", "--num", type=int, help="The number of tests")
+    parser.add_argument(
+        "-p", "--print", action="store_true", help="Fuzzing C AST printer"
+    )
+    parser.add_argument("-i", "--irgen", action="store_true", help="Fuzzing irgen")
+    parser.add_argument(
+        "-r", "--reduce", action="store_true", help="Reducing input file"
+    )
+    parser.add_argument(
+        "--skip-build", action="store_true", help="Skipping cargo build"
+    )
+    parser.add_argument(
+        "--easy", action="store_true", help="Generate more easy code by csmith option"
+    )
+    parser.add_argument(
+        "--seed", type=int, help="Provide seed of fuzz generation", default=-1
+    )
+    parser.add_argument(
+        "--clang-analyze",
+        action="store_true",
+        help="Use clang static analyzer for reducing. It prevents undefined behaviors coming from reduced program, but perhaps take a long time to do so",
+    )
     args = parser.parse_args()
 
     if args.print and args.irgen:
-        raise Exception("Choose an option used for fuzzing: '--print' or '--irgen', NOT both")
-    
+        raise Exception(
+            "Choose an option used for fuzzing: '--print' or '--irgen', NOT both"
+        )
+
     if args.print:
         fuzz_arg = "-p"
     elif args.irgen:
@@ -331,26 +423,41 @@ if __name__ == "__main__":
         raise Exception("Specify fuzzing argument")
 
     if args.seed != -1:
-        print('Set seed as', args.seed)
+        print("Set seed as", args.seed)
         random.seed(args.seed)
     else:
-        print('Use default random seed')
+        print("Use default random seed")
 
     tests_dir = os.path.abspath(os.path.dirname(__file__))
 
     if not args.skip_build:
         print("Building KECC..")
         try:
-            proc = subprocess.Popen(["cargo", "build", "--features=build-bin", "--release", "--bin", "fuzz", "--bin", "kecc"], cwd=tests_dir)
+            proc = subprocess.Popen(
+                [
+                    "cargo",
+                    "build",
+                    "--features=build-bin",
+                    "--release",
+                    "--bin",
+                    "fuzz",
+                    "--bin",
+                    "kecc",
+                ],
+                cwd=tests_dir,
+            )
             proc.communicate()
         except subprocess.TimeoutExpired as e:
             proc.kill()
             raise e
     else:
-        print("Skip building. Please run `cargo build --features=build-bin --release --bin fuzz --bin kecc` to manually build.")
+        print(
+            "Skip building. Please run `cargo build --features=build-bin --release --bin fuzz --bin kecc` to manually build."
+        )
 
     if args.reduce:
         import tqdm
+
         creduce(tests_dir, fuzz_arg, args.clang_analyze)
     else:
         fuzz(tests_dir, fuzz_arg, args.num, args.easy)