added prorate parameter to changing plans on a subscription

src/libs/BillingSubscription.php

@@ -94,10 +94,11 @@ public function create($token = false, $noTrial = false)
      *
      * @param string  $plan    stripe plan id
      * @param boolean $noTrial when true, immediately ends (skips) the trial period for the new subscription
+     * @param boolean $prorate when true, prorates the plan change
      *
      * @return boolean result
      */
-    public function change($plan, $noTrial = false)
+    public function change($plan, $noTrial = false, $prorate = true)
     {
         if (empty($plan) || !in_array($this->status(), ['active', 'trialing', 'past_due', 'unpaid'])
             || $this->model->not_charged) {
@@ -112,7 +113,7 @@ public function change($plan, $noTrial = false)
 
         $params = [
             'plan' => $plan,
-            'prorate' => true,
+            'prorate' => $prorate,
         ];
 
         // maintain the same trial end date if there is one

tests/BillingSubscriptionTest.php

@@ -248,7 +248,7 @@ public function testChange()
         $customer = Mockery::mock('StripeCustomer');
         $customer->shouldReceive('updateSubscription')->withArgs([[
             'plan' => 'blah',
-            'prorate' => true,
+            'prorate' => false,
             'trial_end' => $trialEnds, ]])
             ->andReturn($resultSub)->once();
 
@@ -271,7 +271,7 @@ public function testChange()
 
         $subscription = new BillingSubscription($testModel, 'test', TestBootstrap::app());
 
-        $this->assertTrue($subscription->change('blah'));
+        $this->assertTrue($subscription->change('blah', false, false));
         $this->assertEquals('blah', $subscription->plan());
     }