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.

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