diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 263e360..37e11a4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,6 +1,6 @@
 name: CI
 
-# Run on push only for dev/sandbox
+# Run on push only for ci/staging
 # Otherwise it may trigger concurrently `push & pull_request` on PRs.
 on:
   push:
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index a794f5e..ba50793 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -1,48 +1,33 @@
 name: Main
 
-# Run on push only for dev/sandbox
-# Otherwise it may trigger concurrently `push & pull_request` on PRs.
 on:
+  pull_request: null
   push:
     branches:
       - master
 
 jobs:
   build:
-    name: Python ${{ matrix.python }}
+    name: Linux
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python:
-          - "3.10"
-          - "3.11"
-          - "3.12"
-          - "3.13"
-          - "3.14"
-          - "pypy3.11"
-
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: setup python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
-          python-version: ${{ matrix.python }}
+          python-version: |
+            pypy3.11
+            3.10
+            3.11
+            3.12
+            3.13
+            3.14
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip
-          pip install -e .
-          pip install coveralls --upgrade
-      - name: Run flake8
-        run: |
-          pip install flake8 --upgrade
-          flake8 --exclude=build --ignore=E501,F403,F401,E241,E225,E128 .
-      - name: Run pycodestyle
-        run: |
-          pip install pycodestyle --upgrade
-          pycodestyle --ignore=E128,E261,E225,E501,W605 slugify test.py setup.py
+          python -m pip install coveralls tox tox-uv
       - name: Run test
         run: |
-          coverage run --source=slugify test.py
+          tox
       - name: Coveralls
         run: coveralls --service=github
         env:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f062ed0..400399f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 - Support Python 3.14.
 - Drop support for Python 3.9 and lower.
+- Use tox for local test runs and in CI.
+- Test the project against both `unidecode` and `text_unidecode`.
+- Fix type annotation issues identified by mypy.
+- Run CI against pull requests.
 
 ## 8.0.4
 
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..de62727
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,41 @@
+# coverage
+# --------
+
+[tool.coverage.run]
+relative_files = true
+parallel = true
+branch = true
+source = [
+    "slugify",
+    "test",
+]
+
+[tool.coverage.paths]
+source = [
+    "src",
+    "*/site-packages",
+]
+
+[tool.coverage.report]
+skip_covered = true
+fail_under = 97
+
+
+# mypy
+# ----
+
+[tool.mypy]
+packages = "slugify"
+strict = true
+sqlite_cache = true
+
+
+# pytest
+# ------
+
+[tool.pytest.ini_options]
+testpaths = ["test.py"]
+addopts = "--color=yes"
+filterwarnings = [
+    "error",
+]
diff --git a/slugify/__main__.py b/slugify/__main__.py
index 4cc4616..4e6b3d9 100644
--- a/slugify/__main__.py
+++ b/slugify/__main__.py
@@ -47,7 +47,7 @@ def parse_args(argv: list[str]) -> argparse.Namespace:
         parser.error("Input strings and --stdin cannot work together")
 
     if args.replacements:
-        def split_check(repl):
+        def split_check(repl: str) -> list[str]:
             SEP = '->'
             if SEP not in repl:
                 parser.error("Replacements must be of the form: ORIGINAL{SEP}REPLACED".format(SEP=SEP))
@@ -82,7 +82,7 @@ def slugify_params(args: argparse.Namespace) -> dict[str, Any]:
     )
 
 
-def main(argv: list[str] | None = None):  # pragma: no cover
+def main(argv: list[str] | None = None) -> None:
     """ Run this program """
     if argv is None:
         argv = sys.argv
@@ -94,5 +94,5 @@ def main(argv: list[str] | None = None):  # pragma: no cover
         sys.exit(-1)
 
 
-if __name__ == '__main__':  # pragma: no cover
+if __name__ == '__main__':
     main()
diff --git a/slugify/slugify.py b/slugify/slugify.py
index 67b31c8..9b5f27f 100644
--- a/slugify/slugify.py
+++ b/slugify/slugify.py
@@ -8,7 +8,7 @@
 try:
     import unidecode
 except ImportError:
-    import text_unidecode as unidecode
+    import text_unidecode as unidecode  # type: ignore[import-untyped, no-redef]
 
 __all__ = ['slugify', 'smart_truncate']
 
@@ -67,7 +67,7 @@ def smart_truncate(
             else:
                 if save_order:
                     break
-    if not truncated:  # pragma: no cover
+    if not truncated:
         truncated = string[:max_length]
     return truncated.strip(separator)
 
diff --git a/test.py b/test.py
index d13ef94..fcec4b6 100644
--- a/test.py
+++ b/test.py
@@ -653,5 +653,5 @@ def test_multivalued_options_with_text(self):
         self.assertEqual(params['stopwords'], ['the', 'in', 'a', 'hurry'])
 
 
-if __name__ == '__main__':
+if __name__ == '__main__':  # pragma: nocover
     unittest.main()
diff --git a/tox.ini b/tox.ini
new file mode 100644
index 0000000..0c16f5e
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,69 @@
+[tox]
+env_list =
+    coverage-erase
+    py{3.10, 3.11, 3.12, 3.13, 3.14}-{unidecode, text_unidecode}
+    pypy{3.11}-{unidecode, text_unidecode}
+    coverage-report
+    coverage-html
+    mypy
+    pycodestyle
+
+[testenv]
+depends =
+    py{3.10, 3.11, 3.12, 3.13, 3.14}-{unidecode, text_unidecode}: coverage-erase
+    pypy{3.11}-{unidecode, text_unidecode}: coverage-erase
+deps =
+    coverage[toml]
+    pytest
+    unidecode: pip
+    unidecode: unidecode
+commands_pre:
+    # If testing unidecode, ensure text_unidecode is unavailable.
+    unidecode: pip uninstall --yes text_unidecode
+commands =
+    coverage run -m pytest test.py
+
+[testenv:coverage_base]
+deps =
+    coverage[toml]
+
+[testenv:coverage-erase]
+base = coverage_base
+commands =
+    coverage erase
+
+[testenv:coverage-report]
+base = coverage_base
+depends =
+    py{3.10, 3.11, 3.12, 3.13, 3.14}-{unidecode, text_unidecode}
+    pypy{3.11}-{unidecode, text_unidecode}
+commands_pre =
+    - coverage combine
+commands =
+    coverage report
+
+[testenv:coverage-html]
+base = coverage_base
+depends =
+    coverage-report
+commands =
+    coverage html --fail-under=0
+
+[testenv:mypy]
+deps =
+    mypy
+    unidecode
+commands =
+    mypy
+
+[testenv:pycodestyle]
+deps =
+    pycodestyle
+commands =
+    pycodestyle --ignore=E128,E261,E225,E501,W605 slugify test.py setup.py
+
+[testenv:flake8]
+deps =
+    flake8
+commands =
+    flake8 --ignore=E501,F403,F401,E241,E225,E128 slugify/ setup.py test.py