From d03c4ae8e860e20c27f46cf25ee83d2bbba14906 Mon Sep 17 00:00:00 2001
From: Ismael Celis <ismaelct@gmail.com>
Date: Wed, 30 Mar 2016 01:57:21 -0300
Subject: [PATCH 1/2] Allow Utils.to_number to work with anything that responds
 to #to_number

---
 lib/liquid/utils.rb                      |  6 +++++-
 test/integration/standard_filter_test.rb | 12 ++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/liquid/utils.rb b/lib/liquid/utils.rb
index 4e18138b..f8f5d711 100644
--- a/lib/liquid/utils.rb
+++ b/lib/liquid/utils.rb
@@ -52,7 +52,11 @@ module Liquid
       when String
         (obj.strip =~ /\A\d+\.\d+\z/) ? BigDecimal.new(obj) : obj.to_i
       else
-        0
+        if obj.respond_to?(:to_number)
+          obj.to_number
+        else
+          0
+        end
       end
     end
 
diff --git a/test/integration/standard_filter_test.rb b/test/integration/standard_filter_test.rb
index eb883844..38a43b3f 100644
--- a/test/integration/standard_filter_test.rb
+++ b/test/integration/standard_filter_test.rb
@@ -41,6 +41,16 @@ class TestEnumerable < Liquid::Drop
   end
 end
 
+class NumberLikeThing < Liquid::Drop
+  def initialize(amount)
+    @amount = amount
+  end
+
+  def to_number
+    @amount
+  end
+end
+
 class StandardFiltersTest < Minitest::Test
   include Liquid
 
@@ -391,6 +401,8 @@ class StandardFiltersTest < Minitest::Test
     assert_raises(Liquid::ZeroDivisionError) do
       assert_template_result "4", "{{ 1 | modulo: 0 }}"
     end
+
+    assert_template_result "5", "{{ price | divided_by:2 }}", 'price' => NumberLikeThing.new(10)
   end
 
   def test_modulo

From 929c89789f9cc9eb62513ef571502de2acbcebe5 Mon Sep 17 00:00:00 2001
From: Ismael Celis <ismaelct@gmail.com>
Date: Wed, 30 Mar 2016 13:35:04 -0300
Subject: [PATCH 2/2] Test that all maths filters work with duck-typed
 #to_number

---
 test/integration/standard_filter_test.rb | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/test/integration/standard_filter_test.rb b/test/integration/standard_filter_test.rb
index 38a43b3f..7412f65e 100644
--- a/test/integration/standard_filter_test.rb
+++ b/test/integration/standard_filter_test.rb
@@ -374,11 +374,15 @@ class StandardFiltersTest < Minitest::Test
   def test_plus
     assert_template_result "2", "{{ 1 | plus:1 }}"
     assert_template_result "2.0", "{{ '1' | plus:'1.0' }}"
+
+    assert_template_result "5", "{{ price | plus:'2' }}", 'price' => NumberLikeThing.new(3)
   end
 
   def test_minus
     assert_template_result "4", "{{ input | minus:operand }}", 'input' => 5, 'operand' => 1
     assert_template_result "2.3", "{{ '4.3' | minus:'2' }}"
+
+    assert_template_result "5", "{{ price | minus:'2' }}", 'price' => NumberLikeThing.new(7)
   end
 
   def test_times
@@ -388,6 +392,8 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result "6", "{{ '2.1' | times:3 | replace: '.','-' | plus:0}}"
 
     assert_template_result "7.25", "{{ 0.0725 | times:100 }}"
+
+    assert_template_result "4", "{{ price | times:2 }}", 'price' => NumberLikeThing.new(2)
   end
 
   def test_divided_by
@@ -410,6 +416,8 @@ class StandardFiltersTest < Minitest::Test
     assert_raises(Liquid::ZeroDivisionError) do
       assert_template_result "4", "{{ 1 | modulo: 0 }}"
     end
+
+    assert_template_result "1", "{{ price | modulo:2 }}", 'price' => NumberLikeThing.new(3)
   end
 
   def test_round
@@ -419,6 +427,9 @@ class StandardFiltersTest < Minitest::Test
     assert_raises(Liquid::FloatDomainError) do
       assert_template_result "4", "{{ 1.0 | divided_by: 0.0 | round }}"
     end
+
+    assert_template_result "5", "{{ price | round }}", 'price' => NumberLikeThing.new(4.6)
+    assert_template_result "4", "{{ price | round }}", 'price' => NumberLikeThing.new(4.3)
   end
 
   def test_ceil
@@ -427,6 +438,8 @@ class StandardFiltersTest < Minitest::Test
     assert_raises(Liquid::FloatDomainError) do
       assert_template_result "4", "{{ 1.0 | divided_by: 0.0 | ceil }}"
     end
+
+    assert_template_result "5", "{{ price | ceil }}", 'price' => NumberLikeThing.new(4.6)
   end
 
   def test_floor
@@ -435,6 +448,8 @@ class StandardFiltersTest < Minitest::Test
     assert_raises(Liquid::FloatDomainError) do
       assert_template_result "4", "{{ 1.0 | divided_by: 0.0 | floor }}"
     end
+
+    assert_template_result "5", "{{ price | floor }}", 'price' => NumberLikeThing.new(5.4)
   end
 
   def test_append