Allow passing HTTP::FormData object directly

lib/http/client.rb

@@ -175,7 +175,7 @@ def make_request_body(opts, headers)
       when opts.body
         opts.body
       when opts.form
-        form = HTTP::FormData.create opts.form
+        form = form_data(opts.form)
         headers[Headers::CONTENT_TYPE] ||= form.content_type
         form
       when opts.json
@@ -184,5 +184,9 @@ def make_request_body(opts, headers)
         body
       end
     end
+
+    def form_data(form)
+      (form || {}).respond_to?(:to_h) ? HTTP::FormData.create(form) : form
+    end
   end
 end

spec/lib/http/client_spec.rb

@@ -197,6 +197,20 @@ def simple_response(body, status = 200)
 
       client.get("http://example.com/", :form => {:foo => HTTP::FormData::Part.new("content")})
     end
+
+    context "when passing an HTTP::FormData object directly" do
+      it "creates url encoded form data object" do
+        client = HTTP::Client.new
+        allow(client).to receive(:perform)
+
+        expect(HTTP::Request).to receive(:new) do |opts|
+          expect(opts[:body]).to be_a(HTTP::FormData::Urlencoded)
+          expect(opts[:body].to_s).to eq "foo=bar"
+        end
+
+        client.get("http://example.com/", :form => HTTP::FormData.create({ :foo => "bar" }))
+      end
+    end
   end
 
   describe "passing json" do