diff --git a/lib/cmd/test.js b/lib/cmd/test.js
index 3c3a0af6..4e479015 100644
--- a/lib/cmd/test.js
+++ b/lib/cmd/test.js
@@ -116,7 +116,9 @@ class TestCommand extends Command {
 
     // for power-assert
     if (testArgv.typescript && testArgv.espower) {
-      requireArr.splice(requireArr.indexOf(testArgv.tscompiler), 1);
+      if (requireArr.includes(testArgv.tscompiler)) {
+        requireArr.splice(requireArr.indexOf(testArgv.tscompiler), 1);
+      }
       requireArr.push(testArgv.tscompiler, require.resolve('../espower-typescript'));
     }