Add mobile support to Page

Note that when mobile is true, *both* mobile emulation and touch
support are enabled.

The spec checks whether mobile support has been enabled by checking
for touch support with JavaScript.

Author: duncan-bayne

lib/ferrum/page.rb

@@ -157,9 +157,22 @@ def set_viewport(width:, height:, scale_factor: 0, mobile: false)
         deviceScaleFactor: scale_factor,
         mobile: mobile
       )
+
+      options = if mobile
+                  {
+                    enabled: true,
+                    maxTouchPoints: 1
+                  }
+                else
+                  {
+                    enabled: false
+                  }
+                end
+
+      command("Emulation.setTouchEmulationEnabled", **options)
     end
 
-    def resize(width: nil, height: nil, fullscreen: false)
+    def resize(width: nil, height: nil, fullscreen: false, mobile: false)
       if fullscreen
         width, height = document_size
         self.window_bounds = { window_state: "fullscreen" }
@@ -168,7 +181,7 @@ def resize(width: nil, height: nil, fullscreen: false)
         self.window_bounds = { width: width, height: height }
       end
 
-      set_viewport(width: width, height: height)
+      set_viewport(width: width, height: height, mobile: mobile)
     end
 
     #

spec/page_spec.rb

@@ -235,4 +235,48 @@
       wait_for { message_b }.to eq("goodbye")
     end
   end
+
+  describe "#resize" do
+    def body_size
+      {
+        height: page.evaluate("document.body.clientHeight"),
+        width: page.evaluate("document.body.clientWidth")
+      }
+    end
+
+    def is_mobile?
+      page.evaluate("'ontouchstart' in window || navigator.maxTouchPoints > 0")
+    end
+
+    before do
+      page.go_to("/")
+    end
+
+    context "given a different size" do
+      it "resizes the page" do
+        expect { page.resize(width: 2000, height: 1000) }.to change { body_size }.to(width: 2000, height: 1000)
+      end
+    end
+
+    context "given a zero height" do
+      it "does not change the height" do
+        expect { page.resize(width: 2000, height: 0) }.not_to change { body_size[:height] }
+      end
+    end
+
+    context "given a zero width" do
+      it "does not change the width" do
+        expect { page.resize(width: 0, height: 1000) }.not_to change { body_size[:width] }
+      end
+    end
+
+    context "when mobile is true" do
+      it "enables mobile emulation in the browser" do
+        expect do
+          page.resize(width: 0, height: 0, mobile: true)
+          page.reload
+        end.to change { is_mobile? }.to(true)
+      end
+    end
+  end
 end