control: cancel subscription, not the schedule (#250)

Canceling subscriptions was not updated when switching to treating
subscriptions as the source of truth vs. schedules.

Fixes #249

cmd/tier/tier_test.go

@@ -522,7 +522,7 @@ func TestSubscribe(t *testing.T) {
 					}
 				]
 			}`)
-		case wants(r, "POST", "/v1/subscription_schedules/sub_sched_123/cancel"):
+		case wants(r, "DELETE", "/v1/subscriptions/sub_123"):
 			got.Append(r.URL.Path)
 		default:
 			io.WriteString(w, `{}`)
@@ -531,7 +531,7 @@ func TestSubscribe(t *testing.T) {
 
 	tt.Run("subscribe", "--cancel", "org:test")
 
-	want := []string{"/v1/subscription_schedules/sub_sched_123/cancel"}
+	want := []string{"/v1/subscriptions/sub_123"}
 	diff.Test(t, t.Errorf, got.Load(), want)
 }
 

control/schedule.go

@@ -360,17 +360,17 @@ func (c *Client) updateSchedule(ctx context.Context, schedID, name string, phase
 	return c.Stripe.Do(ctx, "POST", "/v1/subscription_schedules/"+schedID, f, nil)
 }
 
-func (c *Client) cancelSchedule(ctx context.Context, schedID string) (err error) {
-	defer errorfmt.Handlef("stripe: cancelSchedule: %q: %w", schedID, &err)
-	if schedID == "" {
+func (c *Client) cancelSubscription(ctx context.Context, subID string) (err error) {
+	defer errorfmt.Handlef("stripe: cancelSchedule: %q: %w", subID, &err)
+	if subID == "" {
 		return errors.New("subscription id required")
 	}
 	var f stripe.Form
 	// Explicit set to the same as Stripe's defaults to avoid any
 	// surprises.
 	f.Set("invoice_now", true)
 	f.Set("prorate", true)
-	return c.Stripe.Do(ctx, "POST", "/v1/subscription_schedules/"+schedID+"/cancel", f, nil)
+	return c.Stripe.Do(ctx, "DELETE", "/v1/subscriptions/"+subID, f, nil)
 }
 
 func addPhases(ctx context.Context, c *Client, f *stripe.Form, update bool, name string, phases []Phase) error {
@@ -525,7 +525,7 @@ func (c *Client) schedule(ctx context.Context, org string, phases []Phase) (err
 	}
 
 	if cancelNow {
-		return c.cancelSchedule(ctx, s.ScheduleID)
+		return c.cancelSubscription(ctx, s.ID)
 	}
 
 	// TODO(bmizerany): check status?