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Diffstat (limited to 'spec/arel/unit/relations/join_spec.rb')
| -rw-r--r-- | spec/arel/unit/relations/join_spec.rb | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/spec/arel/unit/relations/join_spec.rb b/spec/arel/unit/relations/join_spec.rb new file mode 100644 index 0000000000..f9d0d9561e --- /dev/null +++ b/spec/arel/unit/relations/join_spec.rb @@ -0,0 +1,169 @@ +require File.join(File.dirname(__FILE__), '..', '..', '..', 'spec_helper') + +module Arel + describe Join do + before do + @relation1 = Table.new(:users) + @relation2 = Table.new(:photos) + @predicate = @relation1[:id].eq(@relation2[:user_id]) + end + + describe '==' do + before do + @another_predicate = @relation1[:id].eq(1) + @another_relation = Table.new(:cameras) + end + + it 'obtains if the two relations and the predicate are identical' do + Join.new("INNER JOIN", @relation1, @relation2, @predicate).should == Join.new("INNER JOIN", @relation1, @relation2, @predicate) + Join.new("INNER JOIN", @relation1, @relation2, @predicate).should_not == Join.new("INNER JOIN", @relation1, @another_relation, @predicate) + Join.new("INNER JOIN", @relation1, @relation2, @predicate).should_not == Join.new("INNER JOIN", @relation1, @relation2, @another_predicate) + end + + it 'is commutative on the relations' do + Join.new("INNER JOIN", @relation1, @relation2, @predicate).should == Join.new("INNER JOIN", @relation2, @relation1, @predicate) + end + end + + describe 'hashing' do + it 'implements hash equality' do + Join.new("INNER JOIN", @relation1, @relation2, @predicate) \ + .should hash_the_same_as(Join.new("INNER JOIN", @relation1, @relation2, @predicate)) + end + end + + describe '#prefix_for' do + describe 'when the joined relations are simple' do + it "returns the name of the relation containing the attribute" do + Join.new("INNER JOIN", @relation1, @relation2, @predicate).prefix_for(@relation1[:id]) \ + .should == @relation1.prefix_for(@relation1[:id]) + Join.new("INNER JOIN", @relation1, @relation2, @predicate).prefix_for(@relation2[:id]) \ + .should == @relation2.prefix_for(@relation2[:id]) + + end + end + + describe 'when one of the joined relations is an alias' do + before do + @aliased_relation = @relation1.as(:alias) + end + + it "returns the alias of the relation containing the attribute" do + Join.new("INNER JOIN", @aliased_relation, @relation2, @predicate).prefix_for(@aliased_relation[:id]) \ + .should == @aliased_relation.alias + Join.new("INNER JOIN", @aliased_relation, @relation2, @predicate).prefix_for(@relation2[:id]) \ + .should == @relation2.prefix_for(@relation2[:id]) + end + end + end + + describe '#engine' do + it "delegates to a relation's engine" do + Join.new("INNER JOIN", @relation1, @relation2, @predicate).engine.should == @relation1.engine + end + end + + describe 'when joining simple relations' do + describe '#attributes' do + it 'combines the attributes of the two relations' do + join = Join.new("INNER JOIN", @relation1, @relation2, @predicate) + join.attributes.should == + (@relation1.attributes + @relation2.attributes).collect { |a| a.bind(join) } + end + end + + describe '#to_sql' do + it 'manufactures sql joining the two tables on the predicate' do + Join.new("INNER JOIN", @relation1, @relation2, @predicate).to_sql.should be_like(" + SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id` + FROM `users` + INNER JOIN `photos` ON `users`.`id` = `photos`.`user_id` + ") + end + + it 'manufactures sql joining the two tables, merging any selects' do + Join.new("INNER JOIN", @relation1.select(@relation1[:id].eq(1)), + @relation2.select(@relation2[:id].eq(2)), @predicate).to_sql.should be_like(" + SELECT `users`.`id`, `users`.`name`, `photos`.`id`, `photos`.`user_id`, `photos`.`camera_id` + FROM `users` + INNER JOIN `photos` ON `users`.`id` = `photos`.`user_id` + WHERE `users`.`id` = 1 + AND `photos`.`id` = 2 + ") + end + end + end + + describe 'when joining aggregated relations' do + before do + @aggregation = @relation2 \ + .group(@relation2[:user_id]) \ + .project(@relation2[:user_id], @relation2[:id].count.as(:cnt)) \ + .as('photo_count') + end + + describe '#attributes' do + it 'it transforms aggregate expressions into attributes' do + join_with_aggregation = Join.new("INNER JOIN", @relation1, @aggregation, @predicate) + join_with_aggregation.attributes.should == + (@relation1.attributes + @aggregation.attributes).collect(&:to_attribute).collect { |a| a.bind(join_with_aggregation) } + end + end + + describe '#to_sql' do + describe 'with the aggregation on the right' do + it 'manufactures sql joining the left table to a derived table' do + Join.new("INNER JOIN", @relation1, @aggregation, @predicate).to_sql.should be_like(" + SELECT `users`.`id`, `users`.`name`, `photo_count`.`user_id`, `photo_count`.`cnt` + FROM `users` + INNER JOIN (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY `photos`.`user_id`) AS `photo_count` + ON `users`.`id` = `photo_count`.`user_id` + ") + end + end + + describe 'with the aggregation on the left' do + it 'manufactures sql joining the right table to a derived table' do + Join.new("INNER JOIN", @aggregation, @relation1, @predicate).to_sql.should be_like(" + SELECT `photo_count`.`user_id`, `photo_count`.`cnt`, `users`.`id`, `users`.`name` + FROM (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` GROUP BY `photos`.`user_id`) AS `photo_count` + INNER JOIN `users` + ON `users`.`id` = `photo_count`.`user_id` + ") + end + end + + it "keeps selects on the aggregation within the derived table" do + Join.new("INNER JOIN", @relation1, @aggregation.select(@aggregation[:user_id].eq(1)), @predicate).to_sql.should be_like(" + SELECT `users`.`id`, `users`.`name`, `photo_count`.`user_id`, `photo_count`.`cnt` + FROM `users` + INNER JOIN (SELECT `photos`.`user_id`, COUNT(`photos`.`id`) AS `cnt` FROM `photos` WHERE `photos`.`user_id` = 1 GROUP BY `photos`.`user_id`) AS `photo_count` + ON `users`.`id` = `photo_count`.`user_id` + ") + end + end + end + + describe 'when joining aliased relations' do + it 'aliases the table and attributes properly' do + aliased_relation = @relation1.as(:alias) + @relation1.join(aliased_relation).on(@relation1[:id].eq(aliased_relation[:id])).to_sql.should be_like(" + SELECT `users`.`id`, `users`.`name`, `alias`.`id`, `alias`.`name` + FROM `users` + INNER JOIN `users` AS `alias` + ON `users`.`id` = `alias`.`id` + ") + end + end + + describe 'when joining with a string' do + it "passes the string through to the where clause" do + Join.new("INNER JOIN asdf ON fdsa", @relation1).to_sql.should be_like(" + SELECT `users`.`id`, `users`.`name` + FROM `users` + INNER JOIN asdf ON fdsa + ") + end + end + end +end
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