diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index c62bdc39..d6c83013 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -10,19 +10,19 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10", "3.11"]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install Dependencies
         run: |
           sudo apt remove python3-pip
           python -m pip install --upgrade pip
-          python -m pip install . ruff mypy pytest readme_renderer
+          python -m pip install .[dev]
           pip list
       - name: Type Checker
         run: |
@@ -31,7 +31,7 @@ jobs:
           ruff format --check .
       - name: Run Tests
         run: |
-          ./tests/run_tests.py
+          pytest
       - name: Validate README.md
         # Ensure that the README renders correctly (required for uploading to PyPI).
         run: |
diff --git a/examples/asyncio-python-embed.py b/examples/asyncio-python-embed.py
index 38cc1c20..cb909731 100755
--- a/examples/asyncio-python-embed.py
+++ b/examples/asyncio-python-embed.py
@@ -25,7 +25,7 @@ async def print_counter() -> None:
     Coroutine that prints counters and saves it in a global variable.
     """
     while True:
-        print("Counter: %i" % counter[0])
+        print(f"Counter: {counter[0]}")
         counter[0] += 1
         await asyncio.sleep(3)
 
diff --git a/examples/asyncio-ssh-python-embed.py b/examples/asyncio-ssh-python-embed.py
index 9bbad86f..d0f2d483 100755
--- a/examples/asyncio-ssh-python-embed.py
+++ b/examples/asyncio-ssh-python-embed.py
@@ -44,8 +44,8 @@ async def main(port: int = 8222) -> None:
     def create_server() -> MySSHServer:
         return MySSHServer(lambda: environ)
 
-    print("Listening on :%i" % port)
-    print('To connect, do "ssh localhost -p %i"' % port)
+    print(f"Listening on :{port}")
+    print(f'To connect, do "ssh localhost -p {port}"')
 
     await asyncssh.create_server(
         create_server, "", port, server_host_keys=["/etc/ssh/ssh_host_dsa_key"]
diff --git a/mypy.ini b/mypy.ini
deleted file mode 100644
index 5a7ef2eb..00000000
--- a/mypy.ini
+++ /dev/null
@@ -1,6 +0,0 @@
-[mypy]
-ignore_missing_imports = True
-no_implicit_optional = True
-platform = win32
-strict_equality = True
-strict_optional = True
diff --git a/ptpython/layout.py b/ptpython/layout.py
index 622df594..8f08aa38 100644
--- a/ptpython/layout.py
+++ b/ptpython/layout.py
@@ -108,7 +108,7 @@ def append_category(category: OptionCategory[Any]) -> None:
             tokens.extend(
                 [
                     ("class:sidebar", "  "),
-                    ("class:sidebar.title", "   %-36s" % category.title),
+                    ("class:sidebar.title", f"   {category.title:36}"),
                     ("class:sidebar", "\n"),
                 ]
             )
@@ -130,7 +130,7 @@ def goto_next(mouse_event: MouseEvent) -> None:
             sel = ",selected" if selected else ""
 
             tokens.append(("class:sidebar" + sel, " >" if selected else "  "))
-            tokens.append(("class:sidebar.label" + sel, "%-24s" % label, select_item))
+            tokens.append(("class:sidebar.label" + sel, f"{label:24}", select_item))
             tokens.append(("class:sidebar.status" + sel, " ", select_item))
             tokens.append(("class:sidebar.status" + sel, f"{status}", goto_next))
 
@@ -332,7 +332,7 @@ def get_continuation(
             width: int, line_number: int, is_soft_wrap: bool
         ) -> StyleAndTextTuples:
             if python_input.show_line_numbers and not is_soft_wrap:
-                text = ("%i " % (line_number + 1)).rjust(width)
+                text = f"{line_number + 1} ".rjust(width)
                 return [("class:line-number", text)]
             else:
                 return to_formatted_text(get_prompt_style().in2_prompt(width))
@@ -365,13 +365,9 @@ def get_text_fragments() -> StyleAndTextTuples:
         append((TB, " "))
 
         # Position in history.
-        append(
-            (
-                TB,
-                "%i/%i "
-                % (python_buffer.working_index + 1, len(python_buffer._working_lines)),
-            )
-        )
+        index = python_buffer.working_index + 1
+        lines = len(python_buffer._working_lines)
+        append((TB, f"{index}/{lines} "))
 
         # Shortcuts.
         app = get_app()
@@ -492,8 +488,7 @@ def toggle_sidebar(mouse_event: MouseEvent) -> None:
         ("class:status-toolbar", " - "),
         (
             "class:status-toolbar.python-version",
-            "%s %i.%i.%i"
-            % (platform.python_implementation(), version[0], version[1], version[2]),
+            f"{platform.python_implementation()} {version[0]}.{version[1]}.{version[2]}",
         ),
         ("class:status-toolbar", " "),
     ]
diff --git a/ptpython/repl.py b/ptpython/repl.py
index 6b60018e..aba23f51 100644
--- a/ptpython/repl.py
+++ b/ptpython/repl.py
@@ -362,7 +362,7 @@ async def eval_async(self, line: str) -> object:
 
     def _store_eval_result(self, result: object) -> None:
         locals: dict[str, Any] = self.get_locals()
-        locals["_"] = locals["_%i" % self.current_statement_index] = result
+        locals["_"] = locals[f"_{self.current_statement_index}"] = result
 
     def get_compiler_flags(self) -> int:
         return super().get_compiler_flags() | PyCF_ALLOW_TOP_LEVEL_AWAIT
diff --git a/pyproject.toml b/pyproject.toml
index ce420372..4efffc20 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,51 @@
+[project]
+name = "ptpython"
+version = "3.0.29"
+description = "Python REPL build on top of prompt_toolkit"
+readme = "README.rst"
+authors = [{ name = "Jonathan Slenders" }]
+classifiers = [
+    "License :: OSI Approved :: BSD License",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python",
+]
+requires-python = ">=3.7"
+dependencies = [
+    "appdirs",
+    "importlib_metadata;python_version<'3.8'",
+    "jedi>=0.16.0",
+    # Use prompt_toolkit 3.0.43, because of `OneStyleAndTextTuple` import.
+    "prompt_toolkit>=3.0.43,<3.1.0",
+    "pygments",
+]
+dynamic = ["scripts"]
+
+[project.urls]
+Homepage = "https://github.com/prompt-toolkit/ptpython"
+Changelog = "https://github.com/prompt-toolkit/ptpython/blob/master/CHANGELOG"
+"Bug Tracker" = "https://github.com/prompt-toolkit/ptpython/issues"
+"Source Code" = "https://github.com/prompt-toolkit/ptpython"
+
+[project.optional-dependencies]
+ptipython = ["ipython"] # For ptipython, we need to have IPython
+all = ["black"]         # Black not always possible on PyPy
+dev = ["mypy", "readme_renderer", "ruff", "pytest"]
+
+[tool.mypy]
+ignore_missing_imports = true
+no_implicit_optional = true
+platform = "win32"
+strict_equality = true
+strict_optional = true
+
 [tool.ruff]
 target-version = "py37"
 lint.select = [
@@ -27,9 +75,13 @@ lint.ignore = [
 "ptpython/ipython.py" = ["T100"]  # Import usage.
 "ptpython/repl.py" = ["T201"]  # Print usage.
 "ptpython/printer.py" = ["T201"]  # Print usage.
-"tests/run_tests.py" = ["F401"]  # Unused imports.
+"tests/test_todo.py" = ["F401"]  # Unused imports.
 
 
 [tool.ruff.lint.isort]
 known-first-party = ["ptpython"]
 known-third-party = ["prompt_toolkit", "pygments", "asyncssh"]
+
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 80dfec6a..00000000
--- a/setup.cfg
+++ /dev/null
@@ -1,41 +0,0 @@
-[bdist_wheel]
-universal=1
-
-[flake8]
-exclude=__init__.py
-max_line_length=150
-ignore=
-  E114,
-  E116,
-  E117,
-  E121,
-  E122,
-  E123,
-  E125,
-  E126,
-  E127,
-  E128,
-  E131,
-  E171,
-  E203,
-  E211,
-  E221,
-  E227,
-  E231,
-  E241,
-  E251,
-  E301,
-  E402,
-  E501,
-  E701,
-  E702,
-  E704,
-  E731,
-  E741,
-  F401,
-  F403,
-  F405,
-  F811,
-  W503,
-  W504,
-  E722
diff --git a/setup.py b/setup.py
index aa101764..5ec91484 100644
--- a/setup.py
+++ b/setup.py
@@ -1,51 +1,8 @@
-#!/usr/bin/env python
-import os
 import sys
 
-from setuptools import find_packages, setup
-
-with open(os.path.join(os.path.dirname(__file__), "README.rst")) as f:
-    long_description = f.read()
-
+from setuptools import setup
 
 setup(
-    name="ptpython",
-    author="Jonathan Slenders",
-    version="3.0.29",
-    url="https://github.com/prompt-toolkit/ptpython",
-    description="Python REPL build on top of prompt_toolkit",
-    long_description=long_description,
-    package_urls={
-        "Changelog": "https://github.com/prompt-toolkit/ptpython/blob/master/CHANGELOG",
-    },
-    project_urls={
-        "Bug Tracker": "https://github.com/prompt-toolkit/ptpython/issues",
-        "Source Code": "https://github.com/prompt-toolkit/ptpython",
-        "Changelog": "https://github.com/prompt-toolkit/ptpython/blob/master/CHANGELOG",
-    },
-    packages=find_packages("."),
-    package_data={"ptpython": ["py.typed"]},
-    install_requires=[
-        "appdirs",
-        "importlib_metadata;python_version<'3.8'",
-        "jedi>=0.16.0",
-        # Use prompt_toolkit 3.0.43, because of `OneStyleAndTextTuple` import.
-        "prompt_toolkit>=3.0.43,<3.1.0",
-        "pygments",
-    ],
-    python_requires=">=3.7",
-    classifiers=[
-        "License :: OSI Approved :: BSD License",
-        "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
-        "Programming Language :: Python :: 3.9",
-        "Programming Language :: Python :: 3.10",
-        "Programming Language :: Python :: 3.11",
-        "Programming Language :: Python :: 3.12",
-        "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python",
-    ],
     entry_points={
         "console_scripts": [
             "ptpython = ptpython.entry_points.run_ptpython:run",
@@ -59,9 +16,5 @@
                 *sys.version_info[:2]
             ),
         ]
-    },
-    extras_require={
-        "ptipython": ["ipython"],  # For ptipython, we need to have IPython
-        "all": ["black"],  # Black not always possible on PyPy
-    },
+    }
 )
diff --git a/tests/run_tests.py b/tests/test_todo.py
similarity index 72%
rename from tests/run_tests.py
rename to tests/test_todo.py
index 0de37430..4e8ab37c 100755
--- a/tests/run_tests.py
+++ b/tests/test_todo.py
@@ -1,8 +1,5 @@
-#!/usr/bin/env python
 from __future__ import annotations
 
-import unittest
-
 import ptpython.completer
 import ptpython.eventloop
 import ptpython.filters
@@ -16,9 +13,9 @@
 import ptpython.validator
 
 # For now there are no tests here.
-# However this is sufficient for Travis to do at least a syntax check.
+# However this is sufficient to do at least a syntax check.
 # That way we are at least sure to restrict to the Python 2.6 syntax.
 
 
-if __name__ == "__main__":
-    unittest.main()
+def test_todo():
+    pass