Merge pull request #400 from felixbuenemann/case-node

Implement CASE Conditional Expression

2 files changed, 72 insertions, 0 deletions

diff --git a/test/visitors/test_depth_first.rb b/test/visitors/test_depth_first.rb
index 3356759b7d..1a72789f83 100644
--- a/test/visitors/test_depth_first.rb
+++ b/test/visitors/test_depth_first.rb
@@ -34,6 +34,7 @@ module Arel
         Arel::Nodes::UnqualifiedColumn,
         Arel::Nodes::Top,
         Arel::Nodes::Limit,
+        Arel::Nodes::Else,
       ].each do |klass|
         define_method("test_#{klass.name.gsub('::', '_')}") do
           op = klass.new(:a)
@@ -118,6 +119,7 @@ module Arel
         Arel::Nodes::As,
         Arel::Nodes::DeleteStatement,
         Arel::Nodes::JoinSource,
+        Arel::Nodes::When,
       ].each do |klass|
         define_method("test_#{klass.name.gsub('::', '_')}") do
           binary = klass.new(:a, :b)
@@ -247,6 +249,16 @@ module Arel
         assert_equal [:a, :b, stmt.columns, :c, stmt], @collector.calls
       end
 
+      def test_case
+        node = Arel::Nodes::Case.new
+        node.case = :a
+        node.conditions << :b
+        node.default = :c
+
+        @visitor.accept node
+        assert_equal [:a, :b, node.conditions, :c, node], @collector.calls
+      end
+
       def test_node
         node = Nodes::Node.new
         @visitor.accept node
diff --git a/test/visitors/test_to_sql.rb b/test/visitors/test_to_sql.rb
index 7ae5d5b3af..ea58039529 100644
--- a/test/visitors/test_to_sql.rb
+++ b/test/visitors/test_to_sql.rb
@@ -607,6 +607,66 @@ module Arel
           end
         end
       end
+
+      describe 'Nodes::Case' do
+        it 'supports simple case expressions' do
+          node = Arel::Nodes::Case.new(@table[:name])
+            .when('foo').then(1)
+            .else(0)
+
+          compile(node).must_be_like %{
+            CASE "users"."name" WHEN 'foo' THEN 1 ELSE 0 END
+          }
+        end
+
+        it 'supports extended case expressions' do
+          node = Arel::Nodes::Case.new
+            .when(@table[:name].in(%w(foo bar))).then(1)
+            .else(0)
+
+          compile(node).must_be_like %{
+            CASE WHEN "users"."name" IN ('foo', 'bar') THEN 1 ELSE 0 END
+          }
+        end
+
+        it 'works without default branch' do
+          node = Arel::Nodes::Case.new(@table[:name])
+            .when('foo').then(1)
+
+          compile(node).must_be_like %{
+            CASE "users"."name" WHEN 'foo' THEN 1 END
+          }
+        end
+
+        it 'allows chaining multiple conditions' do
+          node = Arel::Nodes::Case.new(@table[:name])
+            .when('foo').then(1)
+            .when('bar').then(2)
+            .else(0)
+
+          compile(node).must_be_like %{
+            CASE "users"."name" WHEN 'foo' THEN 1 WHEN 'bar' THEN 2 ELSE 0 END
+          }
+        end
+
+        it 'supports #when with two arguments and no #then' do
+          node = Arel::Nodes::Case.new @table[:name]
+
+          { foo: 1, bar: 0 }.reduce(node) { |node, pair| node.when *pair }
+
+          compile(node).must_be_like %{
+            CASE "users"."name" WHEN 'foo' THEN 1 WHEN 'bar' THEN 0 END
+          }
+        end
+
+        it 'can be chained as a predicate' do
+          node = @table[:name].when('foo').then('bar').else('baz')
+
+          compile(node).must_be_like %{
+            CASE "users"."name" WHEN 'foo' THEN 'bar' ELSE 'baz' END
+          }
+        end
+      end
     end
   end
 end