Additional tests: uses default adapter if no adapter is specified on …

…custom block

lib/faraday/rack_builder.rb

@@ -53,6 +53,7 @@ def build(app)
     end
 
     def initialize(handlers = [])
+      @adapter = nil
       @handlers = handlers
       if block_given?
         build(&Proc.new)
@@ -67,6 +68,7 @@ def build(options = {})
       raise_if_locked
       @handlers.clear unless options[:keep]
       yield(self) if block_given?
+      adapter(Faraday.default_adapter) unless @adapter
     end
 
     def [](idx)
@@ -170,7 +172,6 @@ def app
     def to_app(inner_app)
       # last added handler is the deepest and thus closest to the inner app
       # adapter is always the last one
-      adapter(Faraday.default_adapter) unless @adapter
       (@handlers + [@adapter]).reverse.inject(inner_app) { |app, handler| handler.build(app) }
     end
 

test/middleware_stack_test.rb

@@ -21,13 +21,33 @@ def setup
     @builder = @conn.builder
   end
 
-  def test_sets_default_adapter_if_none_set
+  def test_default_stack
     default_middleware = Faraday::Request.lookup_middleware(:url_encoded)
     default_adapter_klass = Faraday::Adapter.lookup_middleware(Faraday.default_adapter)
     assert @builder[0] == default_middleware
     assert @builder.adapter == default_adapter_klass
   end
 
+  def test_sets_default_adapter_if_none_set
+    @conn = Faraday::Connection.new do |_|
+      # custom stack, but missing adapter
+    end
+    @builder = @conn.builder
+    default_adapter_klass = Faraday::Adapter.lookup_middleware(Faraday.default_adapter)
+    assert_nil @builder[0]
+    assert @builder.adapter == default_adapter_klass
+  end
+
+  def test_use_provided_adapter
+    @conn = Faraday::Connection.new do |builder|
+      builder.adapter :test
+    end
+    @builder = @conn.builder
+    test_adapter_klass = Faraday::Adapter.lookup_middleware(:test)
+    assert_nil @builder[0]
+    assert @builder.adapter == test_adapter_klass
+  end
+
   def test_allows_rebuilding
     build_stack Apple
     build_stack Orange