Import Array and Hash tests, and make == blank match behaviour with AS

When ActiveSupport isn't loaded, `[] == blank` is false, but when it is
loaded, it (correctly?) matches the behaviour of `[] == empty`.

I think it's fair to say the intended behaviour is for == blank to match
the behaviour of when AS is loaded, so let's just special-case this.

We also import a bunch of Array and Hash tests here.

lib/liquid/condition.rb

@@ -112,6 +112,8 @@ module Liquid
       if left.is_a?(MethodLiteral)
         if right.respond_to?(left.method_name)
           return right.send(left.method_name)
+        elsif (res = fallback_simulation_of_active_support(left.method_name, right))
+          return res
         else
           return nil
         end
@@ -120,6 +122,8 @@ module Liquid
       if right.is_a?(MethodLiteral)
         if left.respond_to?(right.method_name)
           return left.send(right.method_name)
+        elsif (res = fallback_simulation_of_active_support(right.method_name, left))
+          return res
         else
           return nil
         end
@@ -128,6 +132,17 @@ module Liquid
       left == right
     end
 
+    # ActiveSupport creates #blank? as an alias for #empty? on Hash and Array.
+    # Without this simulation, [] == blank behaves differently when AS is loaded vs. not.
+    def fallback_simulation_of_active_support(method_name, obj)
+      return nil unless method_name == :blank?
+
+      case obj
+      when Array, Hash
+        obj.empty?
+      end # else nil
+    end
+
     def interpret_condition(left, right, op, context)
       # If the operator is empty this means that the decision statement is just
       # a single variable. We can just poll this variable from the context and

test/integration/array_test.rb

@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class ArrayTest < Minitest::Test
+  include Liquid
+
+  def test_array_size
+    assert_template_result("0", "{{a.size}}", { 'a' => [] })
+    assert_template_result("2", "{{a.size}}", { 'a' => [1, 2] })
+  end
+
+  def test_array_first
+    assert_template_result("", "{{a.first}}", { 'a' => [] })
+    assert_template_result("1", "{{a.first}}", { 'a' => [1, 2] })
+  end
+
+  def test_array_last
+    assert_template_result("", "{{a.last}}", { 'a' => [] })
+    assert_template_result("2", "{{a.last}}", { 'a' => [1, 2] })
+  end
+
+  def test_array_index
+    assert_template_result("", "{{a[1]}}", { 'a' => [] })
+    assert_template_result("2", "{{a[1]}}", { 'a' => [1, 2] })
+  end
+
+  def test_negative_array_index
+    assert_template_result("3", "{{a[-1]}}", { 'a' => [1, 2, 3] })
+    assert_template_result("1", "{{a[-3]}}", { 'a' => [1, 2, 3] })
+    assert_template_result("", "{{a[-4]}}", { 'a' => [1, 2, 3] })
+  end
+
+  def test_array_to_s
+    arr = ["a", ["b", 1], "c"]
+    assert_template_result("ab1c", "{{a}}", { 'a' => arr })
+  end
+
+  def test_auto_methods
+    a1 = []
+    a2 = [1, 2, 3, "abc"]
+    assert_template_result("0,nonblank", "{{a.size}},{%if a['size'] == blank%}blank{%else%}nonblank{%endif%}", { 'a' => a1 })
+    assert_template_result("4,nonblank", "{{a.size}},{%if a['size'] == blank%}blank{%else%}nonblank{%endif%}", { 'a' => a2 })
+    assert_template_result(",", "{{a.first}},{{a['first']}}", { 'a' => a1 })
+    assert_template_result("1,", "{{a.first}},{{a['first']}}", { 'a' => a2 })
+    assert_template_result(",", "{{a.last}},{{a['last']}}", { 'a' => a1 })
+    assert_template_result("abc,", "{{a.last}},{{a['last']}}", { 'a' => a2 })
+  end
+
+  def test_array_equality
+    a0 = []
+    a1 = [1]
+    a2 = [1, 2]
+    a3 = [1]
+
+    arrays = [a0, a1, a2, a3]
+    arrays.each_with_index do |a, i|
+      arrays.each_with_index do |b, j|
+        prefix = "(#{i},#{j})"
+        assert_template_result(
+          prefix + (a == b ? "y" : "n"),
+          "#{prefix}{% if a == b %}y{%else%}n{%endif%}",
+          { "a" => a, "b" => b },
+        )
+      end
+    end
+  end
+
+  def test_contains
+    a0 = [1, "a", ["b", "c"], true]
+    a1 = ["b", "c"]
+    a2 = ["B", "C"]
+
+    tpl = "{%if a contains b%}y{%else%}n{%endif%}"
+
+    assert_template_result("y", tpl, { "a" => a0, "b" => 1 })
+    assert_template_result("n", tpl, { "a" => a0, "b" => 2 })
+    assert_template_result("y", tpl, { "a" => a0, "b" => a1 })
+    assert_template_result("n", tpl, { "a" => a0, "b" => a2 })
+  end
+
+  def test_empty
+    assert_template_result("y", "{%if a == empty%}y{%else%}n{%endif%}", { 'a' => [] })
+    assert_template_result("n", "{%if a == empty%}y{%else%}n{%endif%}", { 'a' => [1, 2] })
+  end
+
+  def test_blank
+    assert_template_result("y", "{%if a == blank%}y{%else%}n{%endif%}", { 'a' => [] })
+    assert_template_result("n", "{%if a == blank%}y{%else%}n{%endif%}", { 'a' => [1, 2] })
+  end
+
+  def test_iter
+    a0 = [1, "a"]
+    assert_template_result("1a", "{%for i in a%}{{i}}{%endfor%}", { 'a' => a0 })
+  end
+
+  def test_output
+    a0 = []
+    a1 = [1, "a", ["b", "c"], true]
+    assert_template_result("", "{{a}}", { 'a' => a0 })
+    assert_template_result("1abctrue", "{{a}}", { 'a' => a1 })
+  end
+end

test/integration/hash_test.rb

@@ -0,0 +1,223 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "json"
+
+class HashTest < Minitest::Test
+  include Liquid
+
+  class HashSubclass < Hash
+    def []=(key, value)
+      super(fmt_key(key), value)
+    end
+
+    def [](key)
+      super(fmt_key(key))
+    end
+
+    def key?(key)
+      super(fmt_key(key))
+    end
+
+    def include?(key)
+      super(fmt_key(key))
+    end
+
+    def to_s
+      super.upcase
+    end
+
+    private
+
+    def fmt_key(key)
+      return key unless key.is_a?(String)
+
+      key.upcase
+    end
+  end
+
+  def test_size
+    assert_template_result("0", "{{h.size}}", { "h" => {} })
+    assert_template_result("1", "{{h.size}}", { "h" => { "a" => 1 } })
+  end
+
+  def test_first
+    assert_template_result("", "{{h.first}}", { "h" => {} })
+    assert_template_result("a1", "{{h.first}}", { "h" => { "a" => 1 } })
+  end
+
+  def test_last
+    assert_template_result("", "{{h.last}}", { "h" => { "a" => 1 } })
+  end
+
+  def test_index
+    assert_template_result("", "{{h['a']}}", { "h" => {} })
+    assert_template_result("1", "{{h['a']}}", { "h" => { "a" => 1 } })
+  end
+
+  def test_to_s
+    h = { "a" => 1, "b" => [1, { "c" => 2 }] }
+    assert_template_result("{\"a\"=>1, \"b\"=>[1, {\"c\"=>2}]}", "{{h}}", { "h" => h })
+  end
+
+  def test_auto_methods
+    h1 = { "a" => 1 }
+    h2 = { "last" => 10, "first" => 11, "size" => 12 }
+    assert_template_result("1,nonblank", "{{h.size}},{%if h['size'] == blank%}blank{%else%}nonblank{%endif%}", { "h" => h1 })
+    assert_template_result("12,nonblank", "{{h.size}},{%if h['size'] == blank%}blank{%else%}nonblank{%endif%}", { "h" => h2 })
+    assert_template_result("a1,", "{{h.first}},{{h['first']}}", { "h" => h1 })
+    assert_template_result("11,11", "{{h.first}},{{h['first']}}", { "h" => h2 })
+    assert_template_result(",", "{{h.last}},{{h['last']}}", { "h" => h1 })
+    assert_template_result("10,10", "{{h.last}},{{h['last']}}", { "h" => h2 })
+  end
+
+  def test_equality
+    h0 = {}
+    h1 = { "a" => 1 }
+    h2 = { "a" => 1, "b" => 2 }
+    h3 = { "a" => 1 }
+
+    hashes = [h0, h1, h2, h3]
+    hashes.each_with_index do |a, i|
+      hashes.each_with_index do |b, j|
+        prefix = "(#{i},#{j})"
+        assert_template_result(
+          prefix + (a == b ? "y" : "n"),
+          "#{prefix}{% if a == b %}y{%else%}n{%endif%}",
+          { "a" => a, "b" => b },
+        )
+      end
+    end
+  end
+
+  def test_contains
+    h = { "a" => 1, "b" => { "c" => "d" }, "3" => ["f", 2] }
+
+    tpl = "{%if h contains b%}y{%else%}n{%endif%}"
+
+    assert_template_result("y", tpl, { "h" => h, "b" => "a" })
+    # assert_template_result("y", tpl, h, { "h" => { "b" => "a".html_safe } })
+    assert_template_result("y", tpl, { "h" => h, "b" => "a".b })
+    assert_template_result("n", tpl, { "h" => h, "b" => "A" })
+    # assert_template_result("n", tpl, h, { "h" => { "b" => "A".html_safe } })
+    assert_template_result("n", tpl, { "h" => h, "b" => "A".b })
+
+    assert_template_result("n", tpl, { "h" => h, "b" => 1 })
+    assert_template_result("n", tpl, { "h" => h, "b" => "1" })
+
+    assert_template_result("n", tpl, { "h" => h, "b" => 3 })
+    assert_template_result("y", tpl, { "h" => h, "b" => "3" })
+  end
+
+  def test_empty
+    assert_template_result("y", "{%if h == empty%}y{%else%}n{%endif%}", { "h" => {} })
+    assert_template_result("n", "{%if h == empty%}y{%else%}n{%endif%}", { "h" => { "a" => 1 } })
+  end
+
+  def test_blank
+    assert_template_result("y", "{%if h == blank%}y{%else%}n{%endif%}", { "h" => {} })
+    assert_template_result("n", "{%if h == blank%}y{%else%}n{%endif%}", { "h" => { "a" => 1 } })
+  end
+
+  def test_iter
+    h0 = { "a" => 1, "b" => { "c" => "d" }, "3" => ["f", 2] }
+    assert_template_result("a1b{\"c\"=>\"d\"}3f2", "{%for i in h%}{{i}}{%endfor%}", { "h" => h0 })
+  end
+
+  def test_output
+    h0 = {}
+    h1 = { "a" => 1, "b" => { "c" => "d" }, "3" => ["f", 2] }
+    assert_template_result("{}", "{{h}}", { "h" => h0 })
+    assert_template_result("{\"a\"=>1, \"b\"=>{\"c\"=>\"d\"}, \"3\"=>[\"f\", 2]}", "{{h}}", { "h" => h1 })
+  end
+
+  def test_integer_key
+    h = { 2 => "huh" }
+    assert_template_result("huh", "{{h[2]}}", { "h" => h })
+    assert_template_result("huh", "{{h[b]}}", { "h" => h, "b" => 2 })
+    assert_template_result("", "{{h[b]}}", { "h" => h, "b" => "2" })
+  end
+
+  def test_nil_key
+    assert_hash_roundtrip(nil, nil)
+    refute_hash_roundtrip(nil, "nil")
+    refute_hash_roundtrip(nil, "null")
+  end
+
+  def test_bool_key
+    assert_hash_roundtrip(true, true)
+    refute_hash_roundtrip(true, false)
+    refute_hash_roundtrip(true, "true")
+    refute_hash_roundtrip(true, nil)
+  end
+
+  def test_int_key
+    assert_hash_roundtrip(1, 1)
+    refute_hash_roundtrip(1, 2)
+    refute_hash_roundtrip(1, "1")
+    refute_hash_roundtrip(1, 1.0000000000001)
+  end
+
+  def test_string_key
+    assert_hash_roundtrip("word", "word")
+    # assert_hash_roundtrip("word", "word".html_safe)
+    assert_hash_roundtrip("word", "word".b)
+    refute_hash_roundtrip("word", "word ")
+    refute_hash_roundtrip("word", nil)
+    refute_hash_roundtrip("word", true)
+  end
+
+  def test_weird_keys
+    assert_hash_roundtrip([1, 2], [1, 2])
+    refute_hash_roundtrip([1, 2], [1, 3])
+    assert_hash_roundtrip({ "a" => 1 }, { "a" => 1 })
+    refute_hash_roundtrip({ "a" => 1 }, { "a" => 2 })
+    o = Struct.new(:to_liquid).new(Object.new)
+    # failed_hash_roundtrip(o, o)
+    refute_hash_roundtrip(o, 1)
+    refute_hash_roundtrip(o, nil)
+    assert_hash_roundtrip("\xff".b, "\xff".b)
+    assert_hash_roundtrip(1..2, 1..2)
+    refute_hash_roundtrip(1..2, 1...2)
+    assert_hash_roundtrip(
+      111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111,
+      111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111,
+    )
+    # f64 hashing isn't perfect but we can make some basic assertions.
+    assert_hash_roundtrip(1.1234, 1.1234)
+    refute_hash_roundtrip(1.1234, 1.1)
+  end
+
+  def test_hash_html_key
+    # I mean this is probably not ideal but this is the way liquid works.
+    assert_template_result("{\"a<script>b\"=>\"y\"}", "{{h}}", { "h" => { "a<script>b" => "y" } })
+  end
+
+  def test_hash_subclass
+    hs = HashSubclass.new
+    hs["A"] = "b"
+    assert_template_result("b", "{{h['a']}}", { "h" => hs })
+    assert_template_result("b", "{{h['A']}}", { "h" => hs })
+    assert_template_result("", "{{h['b']}}", { "h" => hs })
+    assert_template_result("yes", "{% if h contains 'a' %}yes{%else%}no{%endif%}", { "h" => hs })
+    assert_template_result('{"A"=>"B"}', "{{h}}", { "h" => hs })
+  end
+
+  private
+
+  def failed_hash_roundtrip(key, test)
+    assert_template_result(
+      "Liquid error (templates/index line 1): internal",
+      "{{h[b]}}",
+      { "h" => { key => "y" }, "b" => test },
+    )
+  end
+
+  def assert_hash_roundtrip(key, test)
+    assert_template_result("y", "{{h[b]}}", { "h" => { key => "y" }, "b" => test })
+  end
+
+  def refute_hash_roundtrip(key, test)
+    assert_template_result("", "{{h[b]}}", { "h" => { key => "y" }, "b" => test })
+  end
+end