diff --git a/vortex-array/src/dtype.rs b/vortex-array/src/dtype.rs
index 04228e215d..0cdc0a49a7 100644
--- a/vortex-array/src/dtype.rs
+++ b/vortex-array/src/dtype.rs
@@ -299,3 +299,15 @@ impl From<PType> for DType {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use std::mem;
+
+    use crate::dtype::DType;
+
+    #[test]
+    fn size_of() {
+        assert_eq!(mem::size_of::<DType>(), 48);
+    }
+}
diff --git a/vortex-array/src/scalar/mod.rs b/vortex-array/src/scalar/mod.rs
index 4bb0c78083..50e09ba180 100644
--- a/vortex-array/src/scalar/mod.rs
+++ b/vortex-array/src/scalar/mod.rs
@@ -169,3 +169,15 @@ impl<T: NativePType> AsBytes for T {
         unsafe { std::slice::from_raw_parts(raw_ptr, std::mem::size_of::<T>()) }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use std::mem;
+
+    use crate::scalar::Scalar;
+
+    #[test]
+    fn size_of() {
+        assert_eq!(mem::size_of::<Scalar>(), 80);
+    }
+}