diff --git a/extensions/action/test/actions.test.ts b/extensions/action/test/actions.test.ts
index 69bdddd..905e74e 100644
--- a/extensions/action/test/actions.test.ts
+++ b/extensions/action/test/actions.test.ts
@@ -210,9 +210,10 @@ describe('Actions Extension', () => {
 
         const abortFn = vi.fn();
 
-        const concurrentAction = action('concurrent-action', async () => {});
+        const concurrentAction = action('concurrent-action', async () => sleep(100));
         const nonConcurrentAction = action('non-concurrent-action', async (_, __, ___, onAbort) => {
             onAbort(abortFn);
+            return sleep(100);
         }, {
             concurrent: false,
         });
@@ -243,6 +244,42 @@ describe('Actions Extension', () => {
         expect(abortFn).toHaveBeenCalled();
     });
 
+    test('Handles custom concurrency methods', async () => {
+        expect.assertions(2);
+
+        const {
+            action,
+        } = instance.store;
+
+        const customConcurrentAction = action('concurrent-action', async (payload: number) => sleep(100), {
+            concurrent: (payload, runningPayloads) => !runningPayloads.includes(payload),
+        });
+
+        let hasCustomConcurrentFailed = false;
+
+        try {
+            await Promise.all([
+                customConcurrentAction(1),
+                customConcurrentAction(2),
+            ]);
+        } catch {
+            hasCustomConcurrentFailed = true;
+        }
+
+        expect(hasCustomConcurrentFailed).toBe(false);
+
+        try {
+            await Promise.all([
+                customConcurrentAction(2),
+                customConcurrentAction(2),
+            ]);
+        } catch {
+            hasCustomConcurrentFailed = true;
+        }
+
+        expect(hasCustomConcurrentFailed).toBe(true);
+    });
+
     test('Handles nested cancellation', async () => {
         expect.assertions(7);
 
@@ -254,8 +291,8 @@ describe('Actions Extension', () => {
 
         const catchAssertion = vi.fn();
 
-        const childAction1 = action('child1', () => sleep(1000));
-        const childAction2 = action('child2', () => sleep(1000));
+        const childAction1 = action('child1', () => sleep(100));
+        const childAction2 = action('child2', () => sleep(100));
         const parentAction = action('parent', (_, __, controller) => Promise.all([
             childAction1(_, controller),
             childAction2(_, controller),