diff --git a/src/cfg_if.rs b/src/cfg_if.rs
new file mode 100644
index 0000000..b7d58e2
--- /dev/null
+++ b/src/cfg_if.rs
@@ -0,0 +1,19 @@
+// cfg blocks
+// https://crates.io/crates/cfg-if
+
+// lib.rs
+cfg_if::cfg_if! {
+    if #[cfg(test)] {
+        pub mod integration_tests;
+        pub const TEST_PATH: &'static str = "src/integration_tests/";
+    } else {
+    }
+}
+
+// calc_engine.rs
+cfg_if::cfg_if! {
+    if #[cfg(test)] {
+        use crate::utils::assert_nodes_rust_vs_ts_test;
+        use crate::TEST_PATH;
+    } else { }
+}
\ No newline at end of file