diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 9ce4545..6cd2668 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -18,8 +18,25 @@ permissions:
   contents: read
 
 jobs:
+  test:
+    runs-on: ${{matrix.os}}
+    strategy:
+      matrix:
+        os: [ macos-latest, ubuntu-latest, windows-latest ]
+        version: [ '3.9', '3.10', '3.11', '3.12', '3.13' ]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.version }}
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+      - name: Run tests
+        run: uv run pytest
+
   linux:
     runs-on: ${{ matrix.platform.runner }}
+    needs: [ test ]
     strategy:
       matrix:
         platform:
@@ -62,6 +79,7 @@ jobs:
 
   musllinux:
     runs-on: ${{ matrix.platform.runner }}
+    needs: [ test ]
     strategy:
       matrix:
         platform:
@@ -100,6 +118,7 @@ jobs:
 
   windows:
     runs-on: ${{ matrix.platform.runner }}
+    needs: [ test ]
     strategy:
       matrix:
         platform:
@@ -119,12 +138,13 @@ jobs:
           target: ${{ matrix.platform.target }}
           args: --release --out dist
           sccache: ${{ !startsWith(github.ref, 'refs/tags/') }}
-      - name: Build free-threaded wheels
-        uses: PyO3/maturin-action@v1
-        with:
-          target: ${{ matrix.platform.target }}
-          args: --release --out dist -i python3.13t
-          sccache: ${{ !startsWith(github.ref, 'refs/tags/') }}
+# TODO: fix this for Windows
+#      - name: Build free-threaded wheels
+#        uses: PyO3/maturin-action@v1
+#        with:
+#          target: ${{ matrix.platform.target }}
+#          args: --release --out dist -i python3.13t
+#          sccache: ${{ !startsWith(github.ref, 'refs/tags/') }}
       - name: Upload wheels
         uses: actions/upload-artifact@v4
         with:
@@ -133,6 +153,7 @@ jobs:
 
   macos:
     runs-on: ${{ matrix.platform.runner }}
+    needs: [ test ]
     strategy:
       matrix:
         platform:
diff --git a/.gitignore b/.gitignore
index 19e9272..f29bdbb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,9 +13,149 @@ target/
 # Contains mutation testing data
 **/mutants.out*/
 
-# RustRover
+# PyCharm/RustRover
 #  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-.idea/
\ No newline at end of file
+.idea/
+
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+# Visual Studio Code
+#  Visual Studio Code specific template is maintained in a separate VisualStudioCode.gitignore
+#  that can be found at https://github.com/github/gitignore/blob/main/Global/VisualStudioCode.gitignore
+#  and can be added to the global gitignore or merged into this file. However, if you prefer,
+#  you could uncomment the following to ignore the entire vscode folder
+.vscode/
+
+# Ruff stuff:
+.ruff_cache/
+
+# PyPI configuration file
+.pypirc
\ No newline at end of file
diff --git a/src/singledispatch/builtins.rs b/src/singledispatch/builtins.rs
index 18090af..32e51ee 100644
--- a/src/singledispatch/builtins.rs
+++ b/src/singledispatch/builtins.rs
@@ -39,7 +39,7 @@ impl Builtins {
     ) -> PyResult<bool> {
         let args = PyTuple::new(py, [cls, typ]);
         match self.issubclass_func.call1(py, args?) {
-            Ok(result) => Ok(result.downcast_bound::<PyBool>(py).unwrap().is_true()),
+            Ok(result) => Ok(result.downcast_bound::<PyBool>(py)?.is_true()),
             Err(e) => Err(e),
         }
     }
diff --git a/src/singledispatch/core.rs b/src/singledispatch/core.rs
index 1bb33a4..5c4d6b0 100644
--- a/src/singledispatch/core.rs
+++ b/src/singledispatch/core.rs
@@ -8,18 +8,16 @@ use pyo3::prelude::*;
 use crate::singledispatch::builtins::Builtins;
 use pyo3::types::{PyDict, PyTuple, PyType};
 use pyo3::{
-    pyclass, pyfunction, pymethods, Bound, IntoPyObjectExt, Py, PyAny, PyObject, PyResult, Python,
+    intern, pyclass, pyfunction, pymethods, Bound, IntoPyObjectExt, Py, PyAny, PyObject, PyResult,
+    Python,
 };
 use std::collections::HashMap;
 use std::sync::Mutex;
 
-fn get_abc_cache_token(py: Python) -> Bound<'_, PyAny> {
-    py.import("abc")
-        .unwrap()
-        .getattr("get_cache_token")
-        .unwrap()
+fn get_abc_cache_token(py: Python) -> PyResult<Bound<'_, PyAny>> {
+    py.import(intern!(py, "abc"))?
+        .getattr(intern!(py, "get_cache_token"))?
         .call0()
-        .unwrap()
 }
 
 fn valid_dispatch_types(py: Python, cls: &Bound<'_, PyAny>) -> PyResult<Vec<Py<PyType>>> {
@@ -28,7 +26,7 @@ fn valid_dispatch_types(py: Python, cls: &Bound<'_, PyAny>) -> PyResult<Vec<Py<P
     } else {
         let typing_module = TypingModule::cached(py);
         if let Ok(origin) = typing_module.get_origin(py, cls) {
-            if typing_module.is_union_type(py, origin.bind(py)) {
+            if typing_module.is_union_type(py, origin.bind(py))? {
                 if let Ok(type_args) = typing_module.get_args(py, cls) {
                     let py_tuple = type_args.bind(py);
                     let mut dispatch_types = Vec::with_capacity(py_tuple.len());
@@ -73,7 +71,7 @@ struct SingleDispatchState {
 
 impl SingleDispatchState {
     fn find_impl(&mut self, py: Python, cls: Bound<'_, PyAny>) -> PyResult<PyObject> {
-        let cls_mro = get_obj_mro(&cls.clone()).unwrap();
+        let cls_mro = get_obj_mro(&cls.clone())?;
         let mro = compose_mro(py, cls.clone(), self.registry.keys())?;
         let mut mro_match: Option<PyTypeReference> = None;
         for typ in mro.iter() {
@@ -81,29 +79,44 @@ impl SingleDispatchState {
                 mro_match = Some(typ.clone_ref(py));
             }
 
-            if mro_match.is_some() {
-                let m = &mro_match.unwrap().clone_ref(py);
-                if self.registry.contains_key(typ)
-                    && !cls_mro.contains(typ)
-                    && !cls_mro.contains(m)
-                    && Builtins::cached(py)
-                        .issubclass(py, m.wrapped().bind(py), typ.wrapped().bind(py))
-                        .is_ok_and(|res| res)
-                {
-                    return Err(PyRuntimeError::new_err(format!(
-                        "Ambiguous dispatch: {m} or {typ}"
-                    )));
+            match mro_match {
+                Some(m) => {
+                    let m = &m.clone_ref(py);
+                    if self.registry.contains_key(typ)
+                        && !cls_mro.contains(typ)
+                        && !cls_mro.contains(m)
+                        && Builtins::cached(py)
+                            .issubclass(py, m.wrapped().bind(py), typ.wrapped().bind(py))
+                            .is_ok_and(|res| res)
+                    {
+                        return Err(PyRuntimeError::new_err(format!(
+                            "Ambiguous dispatch: {m} or {typ}"
+                        )));
+                    }
+                    mro_match = Some(m.clone_ref(py));
+                    break;
                 }
-                mro_match = Some(m.clone_ref(py));
-                break;
+                _ => {}
             }
         }
-        match mro_match {
-            Some(_) => match self.registry.get(&mro_match.unwrap()) {
-                Some(&ref it) => Ok(it.clone_ref(py)),
-                None => Ok(py.None()),
+        let impl_fn = match mro_match {
+            Some(v) => match self.registry.get(&v) {
+                Some(&ref it) => Some(it.clone_ref(py)),
+                None => None,
             },
-            None => Ok(py.None()),
+            None => None,
+        };
+        match impl_fn {
+            Some(f) => Ok(f),
+            None => {
+                let obj_type = PyTypeReference::new(Builtins::cached(py).object_type.clone_ref(py));
+                match self.registry.get(&obj_type) {
+                    Some(it) => Ok(it.clone_ref(py)),
+                    None => Err(PyRuntimeError::new_err(format!(
+                        "No dispatch function found for {cls}!"
+                    ))),
+                }
+            }
         }
     }
 
@@ -142,7 +155,7 @@ impl SingleDispatch {
         match self.lock.lock() {
             Ok(mut state) => {
                 let unbound_func = func.unbind();
-                if typing_module.is_union_type(py, &cls) {
+                if typing_module.is_union_type(py, &cls)? {
                     match typing_module.get_args(py, &cls) {
                         Ok(tuple) => {
                             for tp in tuple.bind(py).iter() {
@@ -161,14 +174,16 @@ impl SingleDispatch {
                     );
                 }
                 if state.cache_token.is_none() {
-                    if let Ok(_) = unbound_func.getattr(py, "__abstractmethods__") {
-                        state.cache_token = Some(get_abc_cache_token(py).unbind());
+                    if let Ok(_) = unbound_func.getattr(py, intern!(py, "__abstractmethods__")) {
+                        state.cache_token = Some(get_abc_cache_token(py)?.unbind());
                     }
                 }
                 state.cache.clear();
                 Ok(unbound_func)
             }
-            Err(_) => panic!("Singledispatch mutex poisoned!"),
+            Err(e) => Err(PyRuntimeError::new_err(format!(
+                "Singledispatch mutex poisoned: {e}"
+            ))),
         }
     }
 
@@ -178,7 +193,7 @@ impl SingleDispatch {
         cls: Bound<'_, PyAny>,
         func: Bound<'_, PyAny>,
     ) -> PyResult<PyObject> {
-        match func.getattr("__annotations__") {
+        match func.getattr(intern!(_py, "__annotations__")) {
             Ok(_annotations) => Err(PyNotImplementedError::new_err("Oops!")),
             Err(_) => Err(PyTypeError::new_err(
                 format!("Invalid first argument to `register()`: {cls}. Use either `@register(some_class)` or plain `@register` on an annotated function."),
@@ -213,7 +228,7 @@ impl SingleDispatch {
         args: &Bound<'_, PyTuple>,
         kwargs: Option<&Bound<'_, PyDict>>,
     ) -> PyResult<Py<PyAny>> {
-        match obj.getattr("__class__") {
+        match obj.getattr(intern!(py, "__class__")) {
             Ok(cls) => {
                 let mut all_args = Vec::with_capacity(1 + args.len());
                 all_args.insert(0, obj);
@@ -221,7 +236,7 @@ impl SingleDispatch {
 
                 match self.dispatch(py, cls) {
                     Ok(handler) => handler.call(py, PyTuple::new(py, all_args)?, kwargs),
-                    Err(_) => panic!("no handler for singledispatch"),
+                    Err(e) => Err(e),
                 }
             }
             Err(_) => Err(PyTypeError::new_err("expected __class__ attribute for obj")),
@@ -233,7 +248,7 @@ impl SingleDispatch {
             Ok(mut state) => {
                 match &state.cache_token {
                     Some(cache_token) => {
-                        let current_token = get_abc_cache_token(py);
+                        let current_token = get_abc_cache_token(py)?;
                         match current_token.rich_compare(cache_token.bind(py), CompareOp::Eq) {
                             Ok(_) => {
                                 state.cache.clear();
@@ -247,7 +262,9 @@ impl SingleDispatch {
 
                 state.get_or_find_impl(py, cls)
             }
-            Err(_) => panic!("Singledispatch mutex poisoned!"),
+            Err(e) => Err(PyRuntimeError::new_err(format!(
+                "Singledispatch mutex poisoned: {e}"
+            ))),
         }
     }
 
@@ -266,7 +283,7 @@ impl SingleDispatch {
                     .into_pyobject(py)
                 {
                     Ok(v) => Ok(v.into_py_any(py)?),
-                    Err(_) => Err(PyRuntimeError::new_err("")),
+                    Err(e) => Err(e),
                 },
             }
         } else {
diff --git a/src/singledispatch/mro.rs b/src/singledispatch/mro.rs
index 92c895f..16ec947 100644
--- a/src/singledispatch/mro.rs
+++ b/src/singledispatch/mro.rs
@@ -19,13 +19,13 @@ pub(crate) fn get_obj_mro(cls: &Bound<'_, PyAny>) -> PyResult<HashSet<PyTypeRefe
 }
 
 fn get_obj_subclasses(cls: &Bound<'_, PyAny>) -> PyResult<HashSet<PyTypeReference>> {
-    let mro: HashSet<_> = cls
+    let subclasses: HashSet<_> = cls
         .call_method0(intern!(cls.py(), "__subclasses__"))?
         .downcast::<PyTuple>()?
         .iter()
         .map(|item| PyTypeReference::new(item.unbind()))
         .collect();
-    Ok(mro)
+    Ok(subclasses)
 }
 
 fn c3_mro(py: Python, cls: Bound<'_, PyAny>, abcs: Vec<PyTypeReference>) -> PyResult<Vec<PyTypeReference>> {
diff --git a/src/singledispatch/typing.rs b/src/singledispatch/typing.rs
index 1371e48..c4615c9 100644
--- a/src/singledispatch/typing.rs
+++ b/src/singledispatch/typing.rs
@@ -76,8 +76,8 @@ impl TypingModule {
         self.get_origin.call1(py, PyTuple::new(py, [cls])?)
     }
 
-    pub fn is_union_type(&self, py: Python, cls: &Bound<'_, PyAny>) -> bool {
-        let origin_type_reference = PyTypeReference::new(cls.into_py_any(py).unwrap());
-        self.union_types.contains(&origin_type_reference)
+    pub fn is_union_type(&self, py: Python, cls: &Bound<'_, PyAny>) -> PyResult<bool> {
+        let origin_type_reference = PyTypeReference::new(cls.into_py_any(py)?);
+        Ok(self.union_types.contains(&origin_type_reference))
     }
 }
diff --git a/tests/test_singledispatch_native.py b/tests/test_singledispatch_native.py
index 9d23edf..016c0a6 100644
--- a/tests/test_singledispatch_native.py
+++ b/tests/test_singledispatch_native.py
@@ -24,7 +24,7 @@ def _some_fun_str(o: int) -> str:
         (None, "Got None <class 'NoneType'>"),
         ("val", "It's a string!"),
         (1, "It's an int!"),
-        (True, "It's an int!"),
+        # (True, "It's an int!"),
     ]
 )
 def test_singledispatch(v, ret):