diff --git a/test/lib.test.mjs b/test/lib.test.mjs
index 752bb32..b97a7d5 100644
--- a/test/lib.test.mjs
+++ b/test/lib.test.mjs
@@ -39,7 +39,23 @@ t.describe('', function() {
     let err = await assert.isRejected(core.run())
     assert.strictEqual(err, assertError)
     assert.strictEqual(module.start.firstCall[0], core.app.http)
-    assert.strictEqual(module.start.firstCall[1], null)
+    assert.strictEqual(module.start.firstCall[1], 4000)
+    assert.strictEqual(module.start.firstCall[2], core.app.ctx)
+  })
+
+  t.test('should support overwriting port', async function() {
+    const assertError = new Error('Inbo')
+    const assertPort = 9382
+    module.start.rejects(assertError)
+    
+    let core = new sc.ServiceCore('testapp', import.meta.url, assertPort)
+
+    await core.init(module)
+    
+    let err = await assert.isRejected(core.run())
+    assert.strictEqual(err, assertError)
+    assert.strictEqual(module.start.firstCall[0], core.app.http)
+    assert.strictEqual(module.start.firstCall[1], assertPort)
     assert.strictEqual(module.start.firstCall[2], core.app.ctx)
   })