diff --git a/app/models/price.rb b/app/models/price.rb
index 03cf6773b..023c981d6 100644
--- a/app/models/price.rb
+++ b/app/models/price.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-MINUTES_PER_HOUR = 60
-SECONDS_PER_MINUTE = 60
+MINUTES_PER_HOUR = 60.0
+SECONDS_PER_MINUTE = 60.0
 
 # Store customized price for various items (Machine, Space), depending on the group and on the plan
 # Also provides a static helper method to compute the price details of a shopping cart
@@ -51,9 +51,9 @@ class Price < ApplicationRecord
       when Machine
         base_amount = reservable.prices.find_by(group_id: user.group_id, plan_id: plan.try(:id)).amount
         if plan
-          space_credit = plan.machine_credits.select { |credit| credit.creditable_id == reservable.id }.first
-          if space_credit
-            hours_available = credits_hours(space_credit, user, new_plan_being_bought)
+          machine_credit = plan.machine_credits.select { |credit| credit.creditable_id == reservable.id }.first
+          if machine_credit
+            hours_available = credits_hours(machine_credit, user, new_plan_being_bought)
             slots.each_with_index do |slot, index|
               total_amount += get_slot_price(base_amount, slot, admin, elements: all_elements, has_credits: (index < hours_available))
             end
diff --git a/test/integration/reservations/create_as_admin_test.rb b/test/integration/reservations/create_as_admin_test.rb
index 164cb06b9..92dd752fc 100644
--- a/test/integration/reservations/create_as_admin_test.rb
+++ b/test/integration/reservations/create_as_admin_test.rb
@@ -57,7 +57,7 @@ module Reservations
       # invoice_items assertions
       invoice_item = InvoiceItem.last
 
-      assert_equal invoice_item.amount, machine.prices.find_by(group_id: @user_without_subscription.group_id, plan_id: nil).amount
+      assert_equal machine.prices.find_by(group_id: @user_without_subscription.group_id, plan_id: nil).amount, invoice_item.amount
 
       # invoice assertions
       invoice = Invoice.find_by(invoiced: reservation)
@@ -244,7 +244,7 @@ module Reservations
       # invoice_items assertions
       invoice_item = InvoiceItem.last
 
-      assert_equal invoice_item.amount, machine.prices.find_by(group_id: @vlonchamp.group_id, plan_id: nil).amount
+      assert_equal machine.prices.find_by(group_id: @vlonchamp.group_id, plan_id: nil).amount, invoice_item.amount
 
       # invoice assertions
       invoice = Invoice.find_by(invoiced: reservation)
diff --git a/test/integration/reservations/create_test.rb b/test/integration/reservations/create_test.rb
index e9d17c1a3..cc1aaf26d 100644
--- a/test/integration/reservations/create_test.rb
+++ b/test/integration/reservations/create_test.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'test_helper'
+
 module Reservations
   class CreateTest < ActionDispatch::IntegrationTest
     setup do
@@ -67,7 +69,7 @@ module Reservations
       # invoice_items assertions
       invoice_item = InvoiceItem.last
 
-      assert_equal invoice_item.amount, machine.prices.find_by(group_id: @user_without_subscription.group_id, plan_id: nil).amount
+      assert_equal machine.prices.find_by(group_id: @user_without_subscription.group_id, plan_id: nil).amount, invoice_item.amount
       assert invoice_item.check_footprint
 
       # invoice assertions
@@ -413,7 +415,7 @@ module Reservations
       # invoice_items assertions
       invoice_item = InvoiceItem.last
 
-      assert_equal invoice_item.amount, machine.prices.find_by(group_id: @vlonchamp.group_id, plan_id: nil).amount
+      assert_equal machine.prices.find_by(group_id: @vlonchamp.group_id, plan_id: nil).amount, invoice_item.amount
       assert invoice_item.check_footprint
 
       # invoice assertions
diff --git a/test/models/availability_test.rb b/test/models/availability_test.rb
index b14e1c70b..3d2b07c65 100644
--- a/test/models/availability_test.rb
+++ b/test/models/availability_test.rb
@@ -1,11 +1,12 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class AvailabilityTest < ActiveSupport::TestCase
-  test "length must be at least 1h" do
+  test 'any duration is allowed' do
     a = Availability.first
     a.end_at = a.start_at + 15.minutes
-    assert a.invalid?
-    assert a.errors.key?(:end_at)
+    assert a.valid?
   end
 
   test "if type available_type is 'machines' check that there is minimum 1 association" do