Allow being explicit about alwaysMatch/firstMatch capabilities

It's now possible to explicitly specify if your desired capabilities
should be sent as alwaysMatch/firstMatch capabilities [1]. The older
implementation defaulted to always use firstMatch which is enough for
most cases. Some examples of usage can be found in the capabilities
specs.

Fixes #9344

[1]: https://www.w3.org/TR/webdriver/#new-session

Author: p0deje

rb/lib/selenium/webdriver/remote/bridge.rb

@@ -49,7 +49,7 @@ def initialize(url:, http_client: nil)
         #
 
         def create_session(capabilities)
-          response = execute(:new_session, {}, {capabilities: {firstMatch: [capabilities]}})
+          response = execute(:new_session, {}, prepare_capabilities_payload(capabilities))
 
           @session_id = response['sessionId']
           capabilities = response['capabilities']
@@ -594,6 +594,11 @@ def element_id_from(id)
           id['ELEMENT'] || id['element-6066-11e4-a52e-4f735466cecf']
         end
 
+        def prepare_capabilities_payload(capabilities)
+          capabilities = {firstMatch: [capabilities]} if !capabilities['alwaysMatch'] && !capabilities['firstMatch']
+          {capabilities: capabilities}
+        end
+
         def convert_locator(how, what)
           how = SearchContext::FINDERS[how.to_sym] || how
 

rb/lib/selenium/webdriver/remote/capabilities.rb

@@ -121,6 +121,14 @@ def internet_explorer(opts = {})
           end
           alias_method :ie, :internet_explorer
 
+          def always_match(capabilities)
+            new(always_match: capabilities)
+          end
+
+          def first_match(*capabilities)
+            new(first_match: capabilities)
+          end
+
           #
           # @api private
           #
@@ -179,8 +187,9 @@ def process_timeouts(caps, timeouts)
         #
 
         def initialize(opts = {})
-          @capabilities = opts
-          self.proxy = opts.delete(:proxy)
+          @capabilities = {}
+          self.proxy = opts.delete(:proxy) if opts[:proxy]
+          @capabilities.merge!(opts)
         end
 
         #
@@ -221,28 +230,9 @@ def proxy=(proxy)
         #
 
         def as_json(*)
-          hash = {}
-
-          @capabilities.each do |key, value|
-            case key
-            when :platform
-              hash['platform'] = value.to_s.upcase
-            when :proxy
-              next unless value
-
-              process_proxy(hash, value)
-            when :unhandled_prompt_behavior
-              hash['unhandledPromptBehavior'] = value.is_a?(Symbol) ? value.to_s.tr('_', ' ') : value
-            when String
-              hash[key.to_s] = value
-            when Symbol
-              hash[self.class.camel_case(key)] = value
-            else
-              raise TypeError, "expected String or Symbol, got #{key.inspect}:#{key.class} / #{value.inspect}"
-            end
+          @capabilities.each_with_object({}) do |(key, value), hash|
+            hash[convert_key(key)] = process_capabilities(key, value, hash)
           end
-
-          hash
         end
 
         def to_json(*)
@@ -263,13 +253,53 @@ def ==(other)
 
         private
 
-        def process_proxy(hash, value)
-          hash['proxy'] = value.as_json
-          hash['proxy']['proxyType'] &&= hash['proxy']['proxyType'].downcase
+        def process_capabilities(key, value, hash)
+          case value
+          when Array
+            value.map { |v| process_capabilities(key, v, hash) }
+          when Hash
+            value.each_with_object({}) do |(k, v), h|
+              h[convert_key(k)] = process_capabilities(k, v, h)
+            end
+          when Capabilities, Options
+            value.as_json
+          else
+            convert_value(key, value)
+          end
+        end
+
+        def convert_key(key)
+          case key
+          when String
+            key.to_s
+          when Symbol
+            self.class.camel_case(key)
+          else
+            raise TypeError, "expected String or Symbol, got #{key.inspect}:#{key.class}"
+          end
+        end
 
-          return unless hash['proxy']['noProxy'].is_a?(String)
+        def convert_value(key, value)
+          case key
+          when :platform
+            value.to_s.upcase
+          when :proxy
+            convert_proxy(value)
+          when :unhandled_prompt_behavior
+            value.is_a?(Symbol) ? value.to_s.tr('_', ' ') : value
+          else
+            value
+          end
+        end
+
+        def convert_proxy(value)
+          return unless value
 
-          hash['proxy']['noProxy'] = hash['proxy']['noProxy'].split(', ')
+          hash = value.as_json
+          hash['proxyType'] &&= hash['proxyType'].downcase
+          hash['noProxy'] = hash['noProxy'].split(', ') if hash['noProxy'].is_a?(String)
+
+          hash
         end
       end # Capabilities
     end # Remote

rb/spec/unit/selenium/webdriver/remote/bridge_spec.rb

@@ -71,6 +71,41 @@ module Remote
             expect(http).to have_received(:request).with(any_args, payload)
           end
 
+          it 'uses alwaysMatch when passed' do
+            payload = JSON.generate(
+              capabilities: {
+                alwaysMatch: {
+                  browserName: 'chrome'
+                }
+              }
+            )
+
+            allow(http).to receive(:request)
+              .with(any_args, payload)
+              .and_return('status' => 200, 'value' => {'sessionId' => 'foo', 'capabilities' => {}})
+
+            bridge.create_session(Capabilities.always_match(Capabilities.chrome).as_json)
+            expect(http).to have_received(:request).with(any_args, payload)
+          end
+
+          it 'uses firstMatch when passed' do
+            payload = JSON.generate(
+              capabilities: {
+                firstMatch: [
+                  {browserName: 'chrome'},
+                  {browserName: 'firefox'}
+                ]
+              }
+            )
+
+            allow(http).to receive(:request)
+              .with(any_args, payload)
+              .and_return('status' => 200, 'value' => {'sessionId' => 'foo', 'capabilities' => {}})
+
+            bridge.create_session(Capabilities.first_match(Capabilities.chrome, Capabilities.firefox).as_json)
+            expect(http).to have_received(:request).with(any_args, payload)
+          end
+
           it 'supports responses with "value" -> "capabilities" capabilities' do
             allow(http).to receive(:request)
               .and_return('value' => {'sessionId' => '', 'capabilities' => {'browserName' => 'firefox'}})

rb/spec/unit/selenium/webdriver/remote/capabilities_spec.rb

@@ -61,7 +61,7 @@ module Remote
         end
 
         it 'should default to no proxy' do
-          expect(Capabilities.new.proxy).to be_nil
+          expect { Capabilities.new.proxy }.to raise_error(KeyError)
         end
 
         it 'can set and get standard capabilities' do
@@ -110,6 +110,21 @@ module Remote
           caps = Capabilities.new(browser_name: 'firefox', 'extension:customCapability': true)
           expect(caps).to eq(Capabilities.json_create(caps.as_json))
         end
+
+        it 'allows to set alwaysMatch' do
+          expected = {'alwaysMatch' => {'browserName' => 'chrome'}}
+          expect(Capabilities.always_match(browser_name: 'chrome').as_json).to eq(expected)
+          expect(Capabilities.always_match('browserName' => 'chrome').as_json).to eq(expected)
+          expect(Capabilities.always_match(Capabilities.chrome).as_json).to eq(expected)
+        end
+
+        it 'allows to set firstMatch' do
+          expected = {'firstMatch' => [{'browserName' => 'chrome'}, {'browserName' => 'firefox'}]}
+          expect(Capabilities.first_match({browser_name: 'chrome'}, {browser_name: 'firefox'}).as_json).to eq(expected)
+          expect(Capabilities.first_match({'browserName' => 'chrome'},
+                                          {'browserName' => 'firefox'}).as_json).to eq(expected)
+          expect(Capabilities.first_match(Capabilities.chrome, Capabilities.firefox).as_json).to eq(expected)
+        end
       end
     end # Remote
   end # WebDriver