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Testing Predicate Query Generation in Ransack

This test suite comprehensively validates the predicate functionality in the Ransack search library, focusing on SQL query generation for various comparison operators and search conditions. The tests ensure proper handling of boolean values, null checks, string matching, and custom predicate definitions.
Test Coverage Overview

The test suite provides extensive coverage of Ransack’s predicate system, including:
Equality and comparison operators (eq, lt, gt, lteq, gteq)
String matching predicates (cont, start, end)
Boolean value handling (true, false)
NULL checking predicates (null, not_null)
Presence validation (blank, present)
Custom predicate definitions
Implementation Analysis

The testing approach uses RSpec’s shared examples and context-specific test cases to verify SQL query generation. The implementation focuses on validating the correct SQL syntax across different database adapters (PostgreSQL, MySQL) and handles special cases like wildcard escaping and large integer values.
Technical Details

Key technical components include:
RSpec as the testing framework
ActiveRecord integration for SQL generation
Database adapter-specific SQL syntax handling
Custom predicate configuration
Shared example patterns for reusable test cases
Best Practices Demonstrated

The test suite exemplifies several testing best practices:
Comprehensive edge case coverage
Database adapter-agnostic testing
Proper test isolation and setup
Shared example usage for DRY testing
Clear test organization and naming
activerecord-hackery/ransack

spec/ransack/predicate_spec.rb
            
require 'spec_helper'

module Ransack
  TRUE_VALUES  = [true,  1, '1', 't', 'T', 'true',  'TRUE'].to_set
  FALSE_VALUES = [false, 0, '0', 'f', 'F', 'false', 'FALSE'].to_set

  describe Predicate do

    before do
      @s = Search.new(Person)
    end

    shared_examples 'wildcard escaping' do |method, regexp|
      it 'automatically converts integers to strings' do
        subject.parent_id_cont = 1
        expect { subject.result }.to_not raise_error
      end

      it "escapes '%', '.', '_' and '\\\\' in value" do
        subject.send(:"#{method}=", '%._\\')
        expect(subject.result.to_sql).to match(regexp)
      end
    end

    describe 'eq' do
      it 'generates an equality condition for boolean true values' do
        test_boolean_equality_for(true)
      end

      it 'generates an equality condition for boolean false values' do
        test_boolean_equality_for(false)
      end

      it 'does not generate a condition for nil' do
        @s.awesome_eq = nil
        expect(@s.result.to_sql).not_to match /WHERE/
      end

      it 'generates a = condition with a huge integer value' do
        val = 123456789012345678901
        @s.salary_eq = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} = #{val}/
      end
    end

    describe 'lteq' do
      it 'generates a <= condition with an integer column' do
        val = 1000
        @s.salary_lteq = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} <= #{val}/
      end

      it 'generates a <= condition with a string column' do
        val = '[email protected]'
        @s.email_lteq = val
        field = "#{quote_table_name("people")}.#{quote_column_name("email")}"
        expect(@s.result.to_sql).to match /#{field} <= '#{val}'/
      end

      it 'does not generate a condition for nil' do
        @s.salary_lteq = nil
        expect(@s.result.to_sql).not_to match /WHERE/
      end

      it 'generates a <= condition with a huge integer value' do
        val = 123456789012345678901
        @s.salary_lteq = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} <= #{val}/
      end
    end

    describe 'lt' do
      it 'generates a < condition with an integer column' do
        val = 2000
        @s.salary_lt = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} < #{val}/
      end

      it 'generates a < condition with a string column' do
        val = '[email protected]'
        @s.email_lt = val
        field = "#{quote_table_name("people")}.#{quote_column_name("email")}"
        expect(@s.result.to_sql).to match /#{field} < '#{val}'/
      end

      it 'does not generate a condition for nil' do
        @s.salary_lt = nil
        expect(@s.result.to_sql).not_to match /WHERE/
      end

      it 'generates a = condition with a huge integer value' do
        val = 123456789012345678901
        @s.salary_lt = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} < #{val}/
      end
    end

    describe 'gteq' do
      it 'generates a >= condition with an integer column' do
        val = 300
        @s.salary_gteq = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} >= #{val}/
      end

      it 'generates a >= condition with a string column' do
        val = '[email protected]'
        @s.email_gteq = val
        field = "#{quote_table_name("people")}.#{quote_column_name("email")}"
        expect(@s.result.to_sql).to match /#{field} >= '#{val}'/
      end

      it 'does not generate a condition for nil' do
        @s.salary_gteq = nil
        expect(@s.result.to_sql).not_to match /WHERE/
      end

      it 'generates a >= condition with a huge integer value' do
        val = 123456789012345678901
        @s.salary_gteq = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} >= #{val}/
      end
    end

    describe 'gt' do
      it 'generates a > condition with an integer column' do
        val = 400
        @s.salary_gt = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} > #{val}/
      end

      it 'generates a > condition with a string column' do
        val = '[email protected]'
        @s.email_gt = val
        field = "#{quote_table_name("people")}.#{quote_column_name("email")}"
        expect(@s.result.to_sql).to match /#{field} > '#{val}'/
      end

      it 'does not generate a condition for nil' do
        @s.salary_gt = nil
        expect(@s.result.to_sql).not_to match /WHERE/
      end

      it 'generates a > condition with a huge integer value' do
        val = 123456789012345678901
        @s.salary_gt = val
        field = "#{quote_table_name("people")}.#{quote_column_name("salary")}"
        expect(@s.result.to_sql).to match /#{field} > #{val}/
      end
    end

    describe 'cont' do
      it_has_behavior 'wildcard escaping', :name_cont,
        (if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
          /"people"."name" ILIKE '%\\%\\.\\_\\\\%'/
        elsif ActiveRecord::Base.connection.adapter_name == "Mysql2"
          /`people`.`name` LIKE '%\\\\%.\\\\_\\\\\\\\%'/
        else
         /"people"."name" LIKE '%%._\\%'/
        end) do
        subject { @s }
      end

      it 'generates a LIKE query with value surrounded by %' do
        @s.name_cont = 'ric'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} I?LIKE '%ric%'/
      end
    end

    describe 'not_cont' do
      it_has_behavior 'wildcard escaping', :name_not_cont,
        (if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
          /"people"."name" NOT ILIKE '%\\%\\.\\_\\\\%'/
        elsif ActiveRecord::Base.connection.adapter_name == "Mysql2"
          /`people`.`name` NOT LIKE '%\\\\%.\\\\_\\\\\\\\%'/
        else
         /"people"."name" NOT LIKE '%%._\\%'/
        end) do
        subject { @s }
      end

      it 'generates a NOT LIKE query with value surrounded by %' do
        @s.name_not_cont = 'ric'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} NOT I?LIKE '%ric%'/
      end
    end

    describe 'i_cont' do
      it_has_behavior 'wildcard escaping', :name_i_cont,
        (if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
          /"people"."name" ILIKE '%\\%\\.\\_\\\\%'/
        elsif ActiveRecord::Base.connection.adapter_name == "Mysql2"
          /LOWER\(`people`.`name`\) LIKE '%\\\\%.\\\\_\\\\\\\\%'/
        else
         /LOWER\("people"."name"\) LIKE '%%._\\%'/
        end) do
        subject { @s }
      end

      it 'generates a LIKE query with LOWER(column) and value surrounded by %' do
        @s.name_i_cont = 'Ric'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /[LOWER\(]?#{field}\)? I?LIKE '%ric%'/
      end
    end

    describe 'not_i_cont' do
      it_has_behavior 'wildcard escaping', :name_not_i_cont,
        (if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
          /"people"."name" NOT ILIKE '%\\%\\.\\_\\\\%'/
        elsif ActiveRecord::Base.connection.adapter_name == "Mysql2"
          /LOWER\(`people`.`name`\) NOT LIKE '%\\\\%.\\\\_\\\\\\\\%'/
        else
         /LOWER\("people"."name"\) NOT LIKE '%%._\\%'/
        end) do
        subject { @s }
      end

      it 'generates a NOT LIKE query with LOWER(column) and value surrounded by %' do
        @s.name_not_i_cont = 'Ric'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /[LOWER\(]?#{field}\)? NOT I?LIKE '%ric%'/
      end
    end

    describe 'start' do
      it 'generates a LIKE query with value followed by %' do
        @s.name_start = 'Er'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} I?LIKE 'Er%'/
      end

      it "works with attribute names ending with '_start'" do
        @s.new_start_start = 'hEy'
        field = "#{quote_table_name("people")}.#{quote_column_name("new_start")}"
        expect(@s.result.to_sql).to match /#{field} I?LIKE 'hEy%'/
      end

      it "works with attribute names ending with '_end'" do
        @s.stop_end_start = 'begin'
        field = "#{quote_table_name("people")}.#{quote_column_name("stop_end")}"
        expect(@s.result.to_sql).to match /#{field} I?LIKE 'begin%'/
      end
    end

    describe 'not_start' do
      it 'generates a NOT LIKE query with value followed by %' do
        @s.name_not_start = 'Eri'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} NOT I?LIKE 'Eri%'/
      end

      it "works with attribute names ending with '_start'" do
        @s.new_start_not_start = 'hEy'
        field = "#{quote_table_name("people")}.#{quote_column_name("new_start")}"
        expect(@s.result.to_sql).to match /#{field} NOT I?LIKE 'hEy%'/
      end

      it "works with attribute names ending with '_end'" do
        @s.stop_end_not_start = 'begin'
        field = "#{quote_table_name("people")}.#{quote_column_name("stop_end")}"
        expect(@s.result.to_sql).to match /#{field} NOT I?LIKE 'begin%'/
      end
    end

    describe 'end' do
      it 'generates a LIKE query with value preceded by %' do
        @s.name_end = 'Miller'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} I?LIKE '%Miller'/
      end

      it "works with attribute names ending with '_start'" do
        @s.new_start_end = 'finish'
        field = "#{quote_table_name("people")}.#{quote_column_name("new_start")}"
        expect(@s.result.to_sql).to match /#{field} I?LIKE '%finish'/
      end

      it "works with attribute names ending with '_end'" do
        @s.stop_end_end = 'Ending'
        field = "#{quote_table_name("people")}.#{quote_column_name("stop_end")}"
        expect(@s.result.to_sql).to match /#{field} I?LIKE '%Ending'/
      end
    end

    describe 'not_end' do
      it 'generates a NOT LIKE query with value preceded by %' do
        @s.name_not_end = 'Miller'
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} NOT I?LIKE '%Miller'/
      end

      it "works with attribute names ending with '_start'" do
        @s.new_start_not_end = 'finish'
        field = "#{quote_table_name("people")}.#{quote_column_name("new_start")}"
        expect(@s.result.to_sql).to match /#{field} NOT I?LIKE '%finish'/
      end

      it "works with attribute names ending with '_end'" do
        @s.stop_end_not_end = 'Ending'
        field = "#{quote_table_name("people")}.#{quote_column_name("stop_end")}"
        expect(@s.result.to_sql).to match /#{field} NOT I?LIKE '%Ending'/
      end
    end

    describe 'true' do
      it 'generates an equality condition for boolean true' do
        @s.awesome_true = true
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} = #{
          ActiveRecord::Base.connection.quoted_true}/
      end

      it 'generates an inequality condition for boolean true' do
        @s.awesome_true = false
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} != #{
          ActiveRecord::Base.connection.quoted_true}/
      end
    end

    describe 'not_true' do
      it 'generates an inequality condition for boolean true' do
        @s.awesome_not_true = true
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} != #{
          ActiveRecord::Base.connection.quoted_true}/
      end

      it 'generates an equality condition for boolean true' do
        @s.awesome_not_true = false
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} = #{
          ActiveRecord::Base.connection.quoted_true}/
      end
    end

    describe 'false' do
      it 'generates an equality condition for boolean false' do
        @s.awesome_false = true
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} = #{
          ActiveRecord::Base.connection.quoted_false}/
      end

      it 'generates an inequality condition for boolean false' do
        @s.awesome_false = false
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} != #{
          ActiveRecord::Base.connection.quoted_false}/
      end
    end

    describe 'not_false' do
      it 'generates an inequality condition for boolean false' do
        @s.awesome_not_false = true
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} != #{
          ActiveRecord::Base.connection.quoted_false}/
      end

      it 'generates an equality condition for boolean false' do
        @s.awesome_not_false = false
        field = "#{quote_table_name("people")}.#{quote_column_name("awesome")}"
        expect(@s.result.to_sql).to match /#{field} = #{
          ActiveRecord::Base.connection.quoted_false}/
      end
    end

    describe 'null' do
      it 'generates a value IS NULL query' do
        @s.name_null = true
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NULL/
      end

      it 'generates a value IS NOT NULL query when assigned false' do
        @s.name_null = false
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NOT NULL/
      end
    end

    describe 'not_null' do
      it 'generates a value IS NOT NULL query' do
        @s.name_not_null = true
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NOT NULL/
      end

      it 'generates a value IS NULL query when assigned false' do
        @s.name_not_null = false
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NULL/
      end

      describe 'with association query' do
        it 'generates a value IS NOT NULL query' do
          @s.comments_id_not_null = true
          sql = @s.result.to_sql
          parent_field = "#{quote_table_name("people")}.#{quote_column_name("id")}"
          expect(sql).to match /#{parent_field} IN/
          field = "#{quote_table_name("comments")}.#{quote_column_name("id")}"
          expect(sql).to match /#{field} IS NOT NULL/
          expect(sql).not_to match /AND NOT/
        end

        it 'generates a value IS NULL query when assigned false' do
          @s.comments_id_not_null = false
          sql = @s.result.to_sql
          parent_field = "#{quote_table_name("people")}.#{quote_column_name("id")}"
          expect(sql).to match /#{parent_field} NOT IN/
          field = "#{quote_table_name("comments")}.#{quote_column_name("id")}"
          expect(sql).to match /#{field} IS NULL/
          expect(sql).to match /AND NOT/
        end
      end
    end

    describe 'present' do
      it %q[generates a value IS NOT NULL AND value != '' query] do
        @s.name_present = true
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NOT NULL AND #{field} != ''/
      end

      it %q[generates a value IS NULL OR value = '' query when assigned false] do
        @s.name_present = false
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NULL OR #{field} = ''/
      end
    end

    describe 'blank' do
      it %q[generates a value IS NULL OR value = '' query] do
        @s.name_blank = true
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NULL OR #{field} = ''/
      end

      it %q[generates a value IS NOT NULL AND value != '' query when assigned false] do
        @s.name_blank = false
        field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
        expect(@s.result.to_sql).to match /#{field} IS NOT NULL AND #{field} != ''/
      end
    end

    context "defining custom predicates" do
      describe "with 'not_in' arel predicate" do
        before do
          Ransack.configure { |c| c.add_predicate "not_in_csv", arel_predicate: "not_in", formatter: proc { |v| v.split(",") } }
        end

        it 'generates a value IS NOT NULL query' do
          @s.name_not_in_csv = ["a", "b"]
          field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
          expect(@s.result.to_sql).to match /#{field} NOT IN \('a', 'b'\)/
        end
      end
    end

    private

      def test_boolean_equality_for(boolean_value)
        query = expected_query(boolean_value)
        test_values_for(boolean_value).each do |value|
          s = Search.new(Person, awesome_eq: value)
          expect(s.result.to_sql).to match query
        end
      end

      def test_values_for(boolean_value)
        case boolean_value
        when true
          TRUE_VALUES
        when false
          FALSE_VALUES
        end
      end

      def expected_query(value, attribute = 'awesome', operator = '=')
        field = "#{quote_table_name("people")}.#{quote_column_name(attribute)}"
        quoted_value = ActiveRecord::Base.connection.quote(value)
        /#{field} #{operator} #{quoted_value}/
      end
    end

end