diff --git a/finlib/src/options/blackscholes/OptionSurface.rs b/finlib/src/options/blackscholes/OptionSurface.rs
index bcb5c3e..faf761f 100644
--- a/finlib/src/options/blackscholes/OptionSurface.rs
+++ b/finlib/src/options/blackscholes/OptionSurface.rs
@@ -157,7 +157,7 @@ mod tests {
         let a = w.walk();
 
         let options = a
-            .par_iter()
+            .iter()
             .map(|v| {
                 let mut call = v.call();
                 let mut put = v.put();