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Testing Liquid Template If/Else Tag Conditions in Shopify/liquid

This integration test suite validates the functionality of Liquid’s if/else tag implementation, covering conditional logic, comparison operators, and nested conditions in template rendering.

Test Coverage Overview

Comprehensive test coverage for Liquid’s conditional logic system.

Key areas tested include:

Basic if/else conditions
Boolean operations (AND/OR)
Variable comparisons
Nested conditionals
Null value handling
Multiple condition chaining

Implementation Analysis

The test suite employs Minitest framework with systematic verification of template rendering outcomes. It uses assert_template_result for comparing expected vs actual output, with thorough coverage of edge cases and operator combinations.

Testing patterns include:

Template string evaluation
Variable assignment testing
Complex boolean logic verification
Custom operator handling

Technical Details

Testing infrastructure includes:

Minitest as the testing framework
Custom assertion helpers
Liquid template engine integration
SyntaxError validation
Condition operator customization capabilities

Best Practices Demonstrated

The test suite exemplifies robust testing practices through comprehensive coverage of conditional logic scenarios. It demonstrates proper error handling, edge case testing, and maintainable test organization.

Notable practices include:

Isolated test cases
Clear test naming conventions
Thorough edge case coverage
Error condition validation

shopify/liquid

test/integration/tags/if_else_tag_test.rb

            
# frozen_string_literal: true

require 'test_helper'

class IfElseTagTest < Minitest::Test
  include Liquid

  def test_if
    assert_template_result('  ', ' {% if false %} this text should not go into the output {% endif %} ')
    assert_template_result(
      '  this text should go into the output  ',
      ' {% if true %} this text should go into the output {% endif %} ',
    )
    assert_template_result('  you rock ?', '{% if false %} you suck {% endif %} {% if true %} you rock {% endif %}?')
  end

  def test_literal_comparisons
    assert_template_result(' NO ', '{% assign v = false %}{% if v %} YES {% else %} NO {% endif %}')
    assert_template_result(' YES ', '{% assign v = nil %}{% if v == nil %} YES {% else %} NO {% endif %}')
  end

  def test_if_else
    assert_template_result(' YES ', '{% if false %} NO {% else %} YES {% endif %}')
    assert_template_result(' YES ', '{% if true %} YES {% else %} NO {% endif %}')
    assert_template_result(' YES ', '{% if "foo" %} YES {% else %} NO {% endif %}')
  end

  def test_if_boolean
    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => true })
  end

  def test_if_or
    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', { 'a' => true, 'b' => true })
    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', { 'a' => true, 'b' => false })
    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', { 'a' => false, 'b' => true })
    assert_template_result('',      '{% if a or b %} YES {% endif %}', { 'a' => false, 'b' => false })

    assert_template_result(' YES ', '{% if a or b or c %} YES {% endif %}', { 'a' => false, 'b' => false, 'c' => true })
    assert_template_result('',      '{% if a or b or c %} YES {% endif %}', { 'a' => false, 'b' => false, 'c' => false })
  end

  def test_if_or_with_operators
    assert_template_result(' YES ', '{% if a == true or b == true %} YES {% endif %}', { 'a' => true, 'b' => true })
    assert_template_result(' YES ', '{% if a == true or b == false %} YES {% endif %}', { 'a' => true, 'b' => true })
    assert_template_result('', '{% if a == false or b == false %} YES {% endif %}', { 'a' => true, 'b' => true })
  end

  def test_comparison_of_strings_containing_and_or_or
    awful_markup = "a == 'and' and b == 'or' and c == 'foo and bar' and d == 'bar or baz' and e == 'foo' and foo and bar"
    assigns      = { 'a' => 'and', 'b' => 'or', 'c' => 'foo and bar', 'd' => 'bar or baz', 'e' => 'foo', 'foo' => true, 'bar' => true }
    assert_template_result(' YES ', "{% if #{awful_markup} %} YES {% endif %}", assigns)
  end

  def test_comparison_of_expressions_starting_with_and_or_or
    assigns = { 'order' => { 'items_count' => 0 }, 'android' => { 'name' => 'Roy' } }
    assert_template_result(
      "YES",
      "{% if android.name == 'Roy' %}YES{% endif %}",
      assigns,
    )
    assert_template_result(
      "YES",
      "{% if order.items_count == 0 %}YES{% endif %}",
      assigns,
    )
  end

  def test_if_and
    assert_template_result(' YES ', '{% if true and true %} YES {% endif %}')
    assert_template_result('', '{% if false and true %} YES {% endif %}')
    assert_template_result('', '{% if true and false %} YES {% endif %}')
  end

  def test_hash_miss_generates_false
    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => {} })
  end

  def test_if_from_variable
    assert_template_result('', '{% if var %} NO {% endif %}', { 'var' => false })
    assert_template_result('', '{% if var %} NO {% endif %}', { 'var' => nil })
    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => { 'bar' => false } })
    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => {} })
    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => nil })
    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => true })

    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => "text" })
    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => true })
    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => 1 })
    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => {} })
    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => [] })
    assert_template_result(' YES ', '{% if "foo" %} YES {% endif %}')
    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => true } })
    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => "text" } })
    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => 1 } })
    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => {} } })
    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => [] } })

    assert_template_result(' YES ', '{% if var %} NO {% else %} YES {% endif %}', { 'var' => false })
    assert_template_result(' YES ', '{% if var %} NO {% else %} YES {% endif %}', { 'var' => nil })
    assert_template_result(' YES ', '{% if var %} YES {% else %} NO {% endif %}', { 'var' => true })
    assert_template_result(' YES ', '{% if "foo" %} YES {% else %} NO {% endif %}', { 'var' => "text" })

    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'foo' => { 'bar' => false } })
    assert_template_result(' YES ', '{% if foo.bar %} YES {% else %} NO {% endif %}', { 'foo' => { 'bar' => true } })
    assert_template_result(' YES ', '{% if foo.bar %} YES {% else %} NO {% endif %}', { 'foo' => { 'bar' => "text" } })
    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'foo' => { 'notbar' => true } })
    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'foo' => {} })
    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'notfoo' => { 'bar' => true } })
  end

  def test_nested_if
    assert_template_result('', '{% if false %}{% if false %} NO {% endif %}{% endif %}')
    assert_template_result('', '{% if false %}{% if true %} NO {% endif %}{% endif %}')
    assert_template_result('', '{% if true %}{% if false %} NO {% endif %}{% endif %}')
    assert_template_result(' YES ', '{% if true %}{% if true %} YES {% endif %}{% endif %}')

    assert_template_result(' YES ', '{% if true %}{% if true %} YES {% else %} NO {% endif %}{% else %} NO {% endif %}')
    assert_template_result(' YES ', '{% if true %}{% if false %} NO {% else %} YES {% endif %}{% else %} NO {% endif %}')
    assert_template_result(' YES ', '{% if false %}{% if true %} NO {% else %} NONO {% endif %}{% else %} YES {% endif %}')
  end

  def test_comparisons_on_null
    assert_template_result('', '{% if null < 10 %} NO {% endif %}')
    assert_template_result('', '{% if null <= 10 %} NO {% endif %}')
    assert_template_result('', '{% if null >= 10 %} NO {% endif %}')
    assert_template_result('', '{% if null > 10 %} NO {% endif %}')

    assert_template_result('', '{% if 10 < null %} NO {% endif %}')
    assert_template_result('', '{% if 10 <= null %} NO {% endif %}')
    assert_template_result('', '{% if 10 >= null %} NO {% endif %}')
    assert_template_result('', '{% if 10 > null %} NO {% endif %}')
  end

  def test_else_if
    assert_template_result('0', '{% if 0 == 0 %}0{% elsif 1 == 1%}1{% else %}2{% endif %}')
    assert_template_result('1', '{% if 0 != 0 %}0{% elsif 1 == 1%}1{% else %}2{% endif %}')
    assert_template_result('2', '{% if 0 != 0 %}0{% elsif 1 != 1%}1{% else %}2{% endif %}')

    assert_template_result('elsif', '{% if false %}if{% elsif true %}elsif{% endif %}')
  end

  def test_syntax_error_no_variable
    assert_raises(SyntaxError) { assert_template_result('', '{% if jerry == 1 %}') }
  end

  def test_syntax_error_no_expression
    assert_raises(SyntaxError) { assert_template_result('', '{% if %}') }
  end

  def test_if_with_custom_condition
    original_op = Condition.operators['contains']
    Condition.operators['contains'] = :[]

    assert_template_result('yes', %({% if 'bob' contains 'o' %}yes{% endif %}))
    assert_template_result('no', %({% if 'bob' contains 'f' %}yes{% else %}no{% endif %}))
  ensure
    Condition.operators['contains'] = original_op
  end

  def test_operators_are_ignored_unless_isolated
    original_op = Condition.operators['contains']
    Condition.operators['contains'] = :[]

    assert_template_result(
      'yes',
      %({% if 'gnomeslab-and-or-liquid' contains 'gnomeslab-and-or-liquid' %}yes{% endif %}),
    )
  ensure
    Condition.operators['contains'] = original_op
  end

  def test_operators_are_whitelisted
    assert_raises(SyntaxError) do
      assert_template_result('', %({% if 1 or throw or or 1 %}yes{% endif %}))
    end
  end

  def test_multiple_conditions
    tpl = "{% if a or b and c %}true{% else %}false{% endif %}"

    tests = {
      [true, true, true] => true,
      [true, true, false] => true,
      [true, false, true] => true,
      [true, false, false] => true,
      [false, true, true] => true,
      [false, true, false] => false,
      [false, false, true] => false,
      [false, false, false] => false,
    }

    tests.each do |vals, expected|
      a, b, c = vals
      assigns = { 'a' => a, 'b' => b, 'c' => c }
      assert_template_result(expected.to_s, tpl, assigns, message: assigns.to_s)
    end
  end
end