diff --git a/heyoka/_test_real128.py b/heyoka/_test_real128.py
index 555c61dd..927b4eb8 100644
--- a/heyoka/_test_real128.py
+++ b/heyoka/_test_real128.py
@@ -119,10 +119,6 @@ def test_scalar(self):
 
         with self.assertRaises(TypeError) as cm:
             real128(prec=7)
-        self.assertTrue(
-            "'prec' is an invalid keyword argument for this function"
-            in str(cm.exception)
-        )
 
         # Conversion to bool.
         self.assertTrue(bool(real128(1)))
diff --git a/pyproject.toml b/pyproject.toml
index 06452337..53c4d2e7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,3 +41,5 @@ sgp4 = ["skyfield"]
 wheel.packages = []
 # Enable IPO.
 cmake.define.HEYOKA_PY_ENABLE_IPO = "ON"
+# Do not include the docs in the sdist.
+sdist.exclude = ["doc"]