diff --git a/Tests/ComposableArchitectureTests/EffectTests.swift b/Tests/ComposableArchitectureTests/EffectTests.swift
index 6e1c3cce3e39..94f28cd92bc5 100644
--- a/Tests/ComposableArchitectureTests/EffectTests.swift
+++ b/Tests/ComposableArchitectureTests/EffectTests.swift
@@ -47,27 +47,29 @@ final class EffectTests: BaseTCATestCase {
   }
 
   func testConcatenateOneEffect() async {
-    let values = LockIsolated<[Int]>([])
-
-    let effect = Effect<Int>.concatenate(
-      .publisher { Just(1).delay(for: 1, scheduler: self.mainQueue) }
-    )
-
-    let task = Task {
-      for await n in effect.actions {
-        values.withValue { $0.append(n) }
+    await withMainSerialExecutor {
+      let values = LockIsolated<[Int]>([])
+      
+      let effect = Effect<Int>.concatenate(
+        .publisher { Just(1).delay(for: 1, scheduler: self.mainQueue) }
+      )
+      
+      let task = Task {
+        for await n in effect.actions {
+          values.withValue { $0.append(n) }
+        }
       }
+      
+      XCTAssertEqual(values.value, [])
+      
+      await self.mainQueue.advance(by: 1)
+      XCTAssertEqual(values.value, [1])
+      
+      await self.mainQueue.run()
+      XCTAssertEqual(values.value, [1])
+      
+      await task.value
     }
-
-    XCTAssertEqual(values.value, [])
-
-    await self.mainQueue.advance(by: 1)
-    XCTAssertEqual(values.value, [1])
-
-    await self.mainQueue.run()
-    XCTAssertEqual(values.value, [1])
-
-    await task.value
   }
 
   func testMerge() async {