diff --git a/internal/capacity/autoscalinggroup_test.go b/internal/capacity/autoscalinggroup_test.go
index 02c0241..10cddb8 100644
--- a/internal/capacity/autoscalinggroup_test.go
+++ b/internal/capacity/autoscalinggroup_test.go
@@ -186,7 +186,7 @@ func expectTerminateInstances(
 		}),
 
 		// For InstanceTerminatedWaiter
-		ec2Mock.EXPECT().DescribeInstances(gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(func(ctx context.Context, input *ec2.DescribeInstancesInput, _ ...func(*ec2.Options)) (*ec2.DescribeInstancesOutput, error) {
+		ec2Mock.EXPECT().DescribeInstances(testutil.AnyContext(), gomock.Any(), gomock.Any()).DoAndReturn(func(ctx context.Context, input *ec2.DescribeInstancesInput, _ ...func(*ec2.Options)) (*ec2.DescribeInstancesOutput, error) {
 			instanceIds := make([]string, len(instancesToTerminate))
 			instances := make([]ec2types.Instance, len(instancesToTerminate))
 			for i, instance := range instancesToTerminate {
@@ -618,7 +618,7 @@ func TestAutoScalingGroup_ReplaceInstances(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		if err := group.ReplaceInstances(context.Background(), drainerMock); err != nil {
+		if err := group.ReplaceInstances(ctx, drainerMock); err != nil {
 			t.Errorf("err = %#v; want nil", err)
 		}
 	})
@@ -751,7 +751,7 @@ func TestAutoScalingGroup_ReduceCapacity(t *testing.T) {
 			Reservations: append(reservationsToTerminate, reservationsToKeep...),
 		}, nil),
 
-		drainerMock.EXPECT().Drain(context.Background(), gomock.Len(len(instancesToTerminate))),
+		drainerMock.EXPECT().Drain(ctx, gomock.Len(len(instancesToTerminate))),
 
 		asMock.EXPECT().DetachInstances(ctx, gomock.Any()).Times(4).Do(func(_ context.Context, input *autoscaling.DetachInstancesInput, _ ...func(options *autoscaling.Options)) {
 			detachedInstanceIds = append(detachedInstanceIds, input.InstanceIds...)
@@ -762,7 +762,7 @@ func TestAutoScalingGroup_ReduceCapacity(t *testing.T) {
 		}),
 
 		// For InstanceTerminatedWaiter
-		ec2Mock.EXPECT().DescribeInstances(gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(func(ctx context.Context, input *ec2.DescribeInstancesInput, _ ...func(*ec2.Options)) (*ec2.DescribeInstancesOutput, error) {
+		ec2Mock.EXPECT().DescribeInstances(testutil.AnyContext(), gomock.Any(), gomock.Any()).DoAndReturn(func(ctx context.Context, input *ec2.DescribeInstancesInput, _ ...func(*ec2.Options)) (*ec2.DescribeInstancesOutput, error) {
 			if !testutil.MatchSlice(input.InstanceIds, terminatedInstanceIds) {
 				t.Errorf("input.InstanceIds = %v; want %v", input.InstanceIds, terminatedInstanceIds)
 			}
diff --git a/internal/capacity/drainer_test.go b/internal/capacity/drainer_test.go
index eef88f3..fb1d132 100644
--- a/internal/capacity/drainer_test.go
+++ b/internal/capacity/drainer_test.go
@@ -14,6 +14,7 @@ import (
 
 	"github.com/abicky/ecsmec/internal/capacity"
 	"github.com/abicky/ecsmec/internal/testing/capacitymock"
+	"github.com/abicky/ecsmec/internal/testing/testutil"
 )
 
 func TestDrainer_Drain(t *testing.T) {
@@ -87,7 +88,7 @@ func TestDrainer_Drain(t *testing.T) {
 
 		ecsMock.EXPECT().UpdateContainerInstancesState(ctx, gomock.Any()).Return(&ecs.UpdateContainerInstancesStateOutput{}, nil)
 		// For ecs.TasksStoppedWaiter
-		ecsMock.EXPECT().DescribeTasks(gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ecs.DescribeTasksInput, _ ...func(*ecs.Options)) (*ecs.DescribeTasksOutput, error) {
+		ecsMock.EXPECT().DescribeTasks(testutil.AnyContext(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ecs.DescribeTasksInput, _ ...func(*ecs.Options)) (*ecs.DescribeTasksOutput, error) {
 			return &ecs.DescribeTasksOutput{
 				Tasks: []ecstypes.Task{
 					{
@@ -97,7 +98,7 @@ func TestDrainer_Drain(t *testing.T) {
 			}, nil
 		})
 		// For ecs.ServicesStableWaiter
-		ecsMock.EXPECT().DescribeServices(gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ecs.DescribeServicesInput, _ ...func(*ecs.Options)) (*ecs.DescribeServicesOutput, error) {
+		ecsMock.EXPECT().DescribeServices(testutil.AnyContext(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ecs.DescribeServicesInput, _ ...func(*ecs.Options)) (*ecs.DescribeServicesOutput, error) {
 			return &ecs.DescribeServicesOutput{
 				Services: []ecstypes.Service{
 					{
@@ -115,7 +116,7 @@ func TestDrainer_Drain(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		if err := drainer.Drain(context.Background(), instanceIDs); err != nil {
+		if err := drainer.Drain(ctx, instanceIDs); err != nil {
 			t.Errorf("err = %#v; want nil", err)
 		}
 	})
@@ -147,7 +148,7 @@ func TestDrainer_Drain(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		if err := drainer.Drain(context.Background(), instanceIDs); err == nil {
+		if err := drainer.Drain(ctx, instanceIDs); err == nil {
 			t.Errorf("err = nil; want non-nil")
 		}
 	})
@@ -245,7 +246,7 @@ func TestDrainer_ProcessInterruptions(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		entries, err := drainer.ProcessInterruptions(context.Background(), messages)
+		entries, err := drainer.ProcessInterruptions(ctx, messages)
 		if err != nil {
 			t.Errorf("err = %#v; want nil", err)
 		}
diff --git a/internal/capacity/spotfleetrequest_test.go b/internal/capacity/spotfleetrequest_test.go
index dd8e41a..063f59b 100644
--- a/internal/capacity/spotfleetrequest_test.go
+++ b/internal/capacity/spotfleetrequest_test.go
@@ -73,7 +73,7 @@ func TestSpotFleetRequest_TerminateAllInstances(t *testing.T) {
 			}),
 
 			// For InstanceTerminatedWaiter
-			ec2Mock.EXPECT().DescribeInstances(gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ec2.DescribeInstancesInput, _ ...func(*ec2.Options)) (*ec2.DescribeInstancesOutput, error) {
+			ec2Mock.EXPECT().DescribeInstances(testutil.AnyContext(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ec2.DescribeInstancesInput, _ ...func(*ec2.Options)) (*ec2.DescribeInstancesOutput, error) {
 				instanceIds := make([]string, len(instances))
 				for i, instance := range instances {
 					instanceIds[i] = *instance.InstanceId
diff --git a/internal/service/service_test.go b/internal/service/service_test.go
index fafde2b..9a28aac 100644
--- a/internal/service/service_test.go
+++ b/internal/service/service_test.go
@@ -67,7 +67,7 @@ func expectCopy(
 		}),
 
 		// For ecs.ServicesStableWaiter
-		ecsMock.EXPECT().DescribeServices(gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(func(ctx context.Context, input *ecs.DescribeServicesInput, _ ...func(*ecs.Options)) (*ecs.DescribeServicesOutput, error) {
+		ecsMock.EXPECT().DescribeServices(testutil.AnyContext(), gomock.Any(), gomock.Any()).DoAndReturn(func(ctx context.Context, input *ecs.DescribeServicesInput, _ ...func(*ecs.Options)) (*ecs.DescribeServicesOutput, error) {
 			if input.Services[0] != dstServiceName {
 				t.Errorf("*input.Service[0] = %s; want %s", input.Services[0], dstServiceName)
 			}
@@ -119,7 +119,7 @@ func expectStopAndDelete(
 		}),
 
 		// For ecs.TasksStoppedWaiter
-		ecsMock.EXPECT().DescribeTasks(gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ecs.DescribeTasksInput, _ ...func(*ecs.Options)) (*ecs.DescribeTasksOutput, error) {
+		ecsMock.EXPECT().DescribeTasks(testutil.AnyContext(), gomock.Any(), gomock.Any()).DoAndReturn(func(_ context.Context, input *ecs.DescribeTasksInput, _ ...func(*ecs.Options)) (*ecs.DescribeTasksOutput, error) {
 			if !reflect.DeepEqual(input.Tasks, runningTaskArns) {
 				t.Errorf("input.Tasks = %#v; want %#v", input.Tasks, runningTaskArns)
 			}
diff --git a/internal/testing/testutil/testutil.go b/internal/testing/testutil/testutil.go
index a0bcf19..0a6550a 100644
--- a/internal/testing/testutil/testutil.go
+++ b/internal/testing/testutil/testutil.go
@@ -1,9 +1,18 @@
 package testutil
 
 import (
+	"context"
+	"reflect"
+
 	"go.uber.org/mock/gomock"
 )
 
+var ctxIface = reflect.TypeOf((*context.Context)(nil)).Elem()
+
+func AnyContext() gomock.Matcher {
+	return gomock.AssignableToTypeOf(ctxIface)
+}
+
 func InOrder(calls ...*gomock.Call) *gomock.Call {
 	args := make([]any, 0, len(calls))
 	for _, call := range calls {