test: added basic world non-null assertion for broadphase

fxgl-entity/src/test/kotlin/com/almasb/fxgl/physics/box2d/dynamics/WorldTest.kt

@@ -0,0 +1,25 @@
+/*
+ * FXGL - JavaFX Game Library. The MIT License (MIT).
+ * Copyright (c) AlmasB (almaslvl@gmail.com).
+ * See LICENSE for details.
+ */
+
+package com.almasb.fxgl.physics.box2d.dynamics
+
+import com.almasb.fxgl.core.math.Vec2
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+
+/**
+ *
+ * @author Almas Baimagambetov (almaslvl@gmail.com)
+ */
+class WorldTest {
+
+    @Test
+    fun `broadphase is not null`() {
+        val world = World(Vec2())
+
+        assertNotNull(world.contactManager.broadPhase)
+    }
+}