diff --git a/fxgl-core/src/test/kotlin/com/almasb/fxgl/core/reflect/ForeignFunctionCallerTest.kt b/fxgl-core/src/test/kotlin/com/almasb/fxgl/core/reflect/ForeignFunctionCallerTest.kt
index 23b9aef35..62919a567 100644
--- a/fxgl-core/src/test/kotlin/com/almasb/fxgl/core/reflect/ForeignFunctionCallerTest.kt
+++ b/fxgl-core/src/test/kotlin/com/almasb/fxgl/core/reflect/ForeignFunctionCallerTest.kt
@@ -7,9 +7,7 @@
 package com.almasb.fxgl.core.reflect
 
 import com.almasb.fxgl.core.util.ResourceExtractor
-import org.hamcrest.CoreMatchers
 import org.hamcrest.CoreMatchers.*
-import org.hamcrest.MatcherAssert
 import org.hamcrest.MatcherAssert.*
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.condition.EnabledIfEnvironmentVariable
@@ -17,8 +15,8 @@ import org.junit.jupiter.api.condition.EnabledOnOs
 import org.junit.jupiter.api.condition.OS
 import java.lang.foreign.FunctionDescriptor
 import java.lang.foreign.ValueLayout
-import java.nio.file.Files
 import java.util.concurrent.CountDownLatch
+import java.util.concurrent.atomic.AtomicInteger
 
 /**
  * @author Almas Baim (https://github.com/AlmasB)
@@ -32,34 +30,35 @@ class ForeignFunctionCallerTest {
         val file = ResourceExtractor.extractNativeLibAsPath("native-lib-test.dll")
 
         val countDown = CountDownLatch(1)
+        val count = AtomicInteger()
 
         val ffc = ForeignFunctionCaller(listOf(file))
+
         ffc.setOnLoaded {
-            countDown.countDown()
-        }
+            ffc.execute {
+                val result = it.call(
+                    "testDownCall",
+                    FunctionDescriptor.of(
+                        ValueLayout.JAVA_INT,
+                        ValueLayout.JAVA_INT
+                    ),
+                    5
+                ) as Int
 
-        ffc.load()
+                count.set(result)
+            }
 
-        ffc.execute {
-            val result = it.call(
-                "testDownCall",
-                FunctionDescriptor.of(
-                    ValueLayout.JAVA_INT,
-                    ValueLayout.JAVA_INT
-                ),
-                5
-            ) as Int
+            ffc.unload()
+        }
 
-            assertThat(result, `is`(25))
+        ffc.setOnUnloaded {
+            countDown.countDown()
         }
 
-        ffc.unload()
+        ffc.load()
 
         countDown.await()
 
-        // block some time until the native lib is fully unloaded
-        Thread.sleep(2500)
-
-        Files.deleteIfExists(file)
+        assertThat(count.get(), `is`(25))
     }
 }
\ No newline at end of file