diff --git a/crates/uv-python/src/discovery.rs b/crates/uv-python/src/discovery.rs
index cda59cf93..ad8d59e69 100644
--- a/crates/uv-python/src/discovery.rs
+++ b/crates/uv-python/src/discovery.rs
@@ -2316,6 +2316,20 @@ mod tests {
             ),
             "Pre-release version requests require a patch version of zero"
         );
+        assert!(
+            matches!(
+                VersionRequest::from_str("3.12-dev"),
+                Err(Error::InvalidVersionRequest(_))
+            ),
+            "Development version segments are not allowed"
+        );
+        assert!(
+            matches!(
+                VersionRequest::from_str("3.12.post0"),
+                Err(Error::InvalidVersionRequest(_))
+            ),
+            "Post version segments are not allowed"
+        );
         assert!(
             // Test for overflow
             matches!(