diff --git a/docs/usage/configuration.md b/docs/usage/configuration.md
index e3867bd9f..df4b940e0 100644
--- a/docs/usage/configuration.md
+++ b/docs/usage/configuration.md
@@ -128,7 +128,7 @@ argument "`min`":
 
 ```{code-cell} python
 ---
-tags: [raises-exception]
+tags: [warns]
 ---
 @magicgui(a_string={'min': 10})
 def whoops(a_string: str = 'Hi there'):
diff --git a/examples/forward_refs.py b/examples/napari_forward_refs.py
similarity index 100%
rename from examples/forward_refs.py
rename to examples/napari_forward_refs.py
diff --git a/magicgui/widgets/_concrete.py b/magicgui/widgets/_concrete.py
index e26b6152e..1c27aa41b 100644
--- a/magicgui/widgets/_concrete.py
+++ b/magicgui/widgets/_concrete.py
@@ -212,7 +212,8 @@ def _value_from_position(self, position):
 
     def _position_from_value(self, value):
         minv = math.log(self.min, self.base)
-        return (math.log(value, self.base) - minv) / self._scale + self._min_pos
+        pos = (math.log(value, self.base) - minv) / self._scale + self._min_pos
+        return int(pos)
 
     @property
     def base(self):
diff --git a/tests/test_docs.py b/tests/test_docs.py
new file mode 100644
index 000000000..e9ffa6b2c
--- /dev/null
+++ b/tests/test_docs.py
@@ -0,0 +1,49 @@
+import re
+import runpy
+from glob import glob
+from pathlib import Path
+
+import pytest
+
+from magicgui import use_app
+
+
+@pytest.mark.parametrize(
+    "fname",
+    [
+        f
+        for f in glob("docs/**/*.md", recursive=True)
+        if "_build" not in f and Path(f).read_text(encoding="utf-8").startswith("-")
+    ],
+)
+def test_doc_code_cells(fname, globalns=globals()):
+    """Make sure that all code cells in documentation perform as expected."""
+    text = Path(fname).read_text()
+    code_cells = re.findall(r"```{code-cell}[^\n]+\n(.*?)`{3}", text, re.S)
+    for cell in code_cells:
+        header = re.search(r"-{3}(.+?)-{3}", cell, re.S)
+        if header:
+            cell = cell.replace(header.group(), "")
+            if "warns" in header.group():
+                with pytest.warns(None):
+                    exec(cell, globalns)
+                    continue
+            if "raises-exception" in header.group():
+                with pytest.raises(Exception):
+                    exec(cell, globalns)
+                    continue
+        exec(cell, globalns)
+
+
+@pytest.mark.parametrize(
+    "fname", [f for f in glob("examples/*.py") if "napari" not in f]
+)
+def test_examples(fname):
+    """Make sure that all code cells in documentation perform as expected."""
+    app = use_app()
+    app.start_timer(0, app.quit)
+    if "OLD" in fname:
+        with pytest.warns(FutureWarning):
+            assert runpy.run_path(fname)
+    else:
+        assert runpy.run_path(fname)