[Liquid] Add round, ceil and floor standard filters

lib/liquid/standardfilters.rb

@@ -243,6 +243,21 @@ module Liquid
       apply_operation(input, operand, :%)
     end
 
+    def round(input, n = 0)
+      result = to_number(input).round(to_number(n))
+      result = result.to_f if result.is_a?(BigDecimal)
+      result = result.to_i if n == 0
+      result
+    end
+
+    def ceil(input)
+      to_number(input).ceil.to_i
+    end
+
+    def floor(input)
+      to_number(input).floor.to_i
+    end
+
     def default(input, default_value = "".freeze)
       is_blank = input.respond_to?(:empty?) ? input.empty? : !input
       is_blank ? default_value : input

test/integration/standard_filter_test.rb

@@ -273,6 +273,22 @@ class StandardFiltersTest < Test::Unit::TestCase
     assert_template_result "1", "{{ 3 | modulo:2 }}"
   end
 
+  def test_round
+    assert_template_result "5", "{{ input | round }}", 'input' => 4.6
+    assert_template_result "4", "{{ '4.3' | round }}"
+    assert_template_result "4.56", "{{ input | round: 2 }}", 'input' => 4.5612
+  end
+
+  def test_ceil
+    assert_template_result "5", "{{ input | ceil }}", 'input' => 4.6
+    assert_template_result "5", "{{ '4.3' | ceil }}"
+  end
+
+  def test_floor
+    assert_template_result "4", "{{ input | floor }}", 'input' => 4.6
+    assert_template_result "4", "{{ '4.3' | floor }}"
+  end
+
   def test_append
     assigns = {'a' => 'bc', 'b' => 'd' }
     assert_template_result('bcd',"{{ a | append: 'd'}}",assigns)