diff --git a/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt b/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
index 51972ab..f4d2c27 100644
--- a/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
+++ b/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
@@ -188,6 +188,8 @@
 
     val lastModifiedTimeBeforeRunningFormatter =
         Files.getLastModifiedTime(unformattedFilePath).toMillis()
+    // The test may run under 1ms, and we need to make sure the new file timestamp will be different
+    Thread.sleep(100)
     Main(emptyInput, PrintStream(out), PrintStream(err), arrayOf(unformattedFile.toString())).run()
     val lastModifiedTimeAfterRunningFormatter =
         Files.getLastModifiedTime(unformattedFilePath).toMillis()