diff --git a/src/META-INF/test-formula.cdkdepends b/src/META-INF/test-formula.cdkdepends
index 51aedd4bdae..e4e997d5314 100644
--- a/src/META-INF/test-formula.cdkdepends
+++ b/src/META-INF/test-formula.cdkdepends
@@ -9,3 +9,4 @@ cdk-formula.jar
 cdk-extra.jar
 cdk-smiles.jar
 cdk-valencycheck.jar
+cdk-io.jar