diff --git a/test/slow-big.test.js b/test/slow-big.test.js
index 5b7141d..82bf6e7 100644
--- a/test/slow-big.test.js
+++ b/test/slow-big.test.js
@@ -301,4 +301,5 @@ describe('argon2 crosstest', () => {
 });
 
 // non parallel: 14h, parallel: ~1h
+process.env.MSHOULD_FAST = '1';
 should.runWhen(import.meta.url);
diff --git a/test/slow-dos.test.js b/test/slow-dos.test.js
index 23d5e11..2844966 100644
--- a/test/slow-dos.test.js
+++ b/test/slow-dos.test.js
@@ -195,4 +195,5 @@ should(
 );
 
 // takes ~20min
+process.env.MSHOULD_FAST = '1';
 should.runWhen(import.meta.url);