diff --git a/src/ast.rs b/src/ast.rs
index 81ba4b76..897bc956 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -2323,43 +2323,3 @@ impl Expr {
         true
     }
 }
-
-#[cfg(test)]
-mod tests {
-    /// This test is to make sure no code changes increase the sizes of critical data structures.
-    #[test]
-    fn check_struct_sizes() {
-        use crate::*;
-        use std::mem::size_of;
-
-        let packed = cfg!(all(
-            target_pointer_width = "32",
-            feature = "only_i32",
-            feature = "no_float"
-        ));
-
-        assert_eq!(size_of::<Dynamic>(), if packed { 8 } else { 16 });
-        assert_eq!(size_of::<Option<Dynamic>>(), if packed { 8 } else { 16 });
-        #[cfg(not(feature = "no_position"))]
-        assert_eq!(size_of::<Position>(), 4);
-        assert_eq!(size_of::<ast::Expr>(), 16);
-        assert_eq!(size_of::<Option<ast::Expr>>(), 16);
-        assert_eq!(size_of::<ast::Stmt>(), 32);
-        assert_eq!(size_of::<Option<ast::Stmt>>(), 32);
-        assert_eq!(
-            size_of::<FnPtr>(),
-            if cfg!(feature = "no_smartstring") {
-                80
-            } else {
-                96
-            }
-        );
-        assert_eq!(size_of::<Scope>(), 464);
-        assert_eq!(size_of::<LexError>(), 56);
-        assert_eq!(
-            size_of::<ParseError>(),
-            if cfg!(feature = "no_position") { 8 } else { 16 }
-        );
-        assert_eq!(size_of::<EvalAltResult>(), 72);
-    }
-}
diff --git a/src/lib.rs b/src/lib.rs
index 1466bbb7..e7853cda 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -93,6 +93,7 @@ pub mod packages;
 mod parse;
 pub mod plugin;
 mod scope;
+mod tests;
 mod token;
 mod r#unsafe;
 
diff --git a/src/tests.rs b/src/tests.rs
new file mode 100644
index 00000000..3331b50f
--- /dev/null
+++ b/src/tests.rs
@@ -0,0 +1,39 @@
+//! Module containing unit tests.
+#![cfg(test)]
+
+/// This test is to make sure no code changes increase the sizes of critical data structures.
+#[test]
+fn check_struct_sizes() {
+    use crate::*;
+    use std::mem::size_of;
+
+    const PACKED: bool = cfg!(all(
+        target_pointer_width = "32",
+        feature = "only_i32",
+        feature = "no_float"
+    ));
+
+    assert_eq!(size_of::<Dynamic>(), if PACKED { 8 } else { 16 });
+    assert_eq!(size_of::<Option<Dynamic>>(), if PACKED { 8 } else { 16 });
+    #[cfg(not(feature = "no_position"))]
+    assert_eq!(size_of::<Position>(), 4);
+    assert_eq!(size_of::<ast::Expr>(), 16);
+    assert_eq!(size_of::<Option<ast::Expr>>(), 16);
+    assert_eq!(size_of::<ast::Stmt>(), 32);
+    assert_eq!(size_of::<Option<ast::Stmt>>(), 32);
+    assert_eq!(
+        size_of::<FnPtr>(),
+        if cfg!(feature = "no_smartstring") {
+            80
+        } else {
+            96
+        }
+    );
+    assert_eq!(size_of::<Scope>(), 464);
+    assert_eq!(size_of::<LexError>(), 56);
+    assert_eq!(
+        size_of::<ParseError>(),
+        if cfg!(feature = "no_position") { 8 } else { 16 }
+    );
+    assert_eq!(size_of::<EvalAltResult>(), 72);
+}