added a ui test that forces experiment results

app/views/whiplash_sessions/index.html.haml

@@ -15,3 +15,4 @@
         = label_tag k, nil, {:style => "float:left;width:375px"}
         = text_field_tag k, session[k], :style => "float:left"
       = submit_tag "Update"
+    <div style="clear:both">

spec/smoke/signing_experiments.rb

@@ -0,0 +1,26 @@
+require 'smoke_spec_helper.rb'
+
+describe "showing the thermometer" do
+  before(:all) do
+    @petition = create_a_petition
+  end
+  it "should be visible" do
+    force_experiment_result("show thermometer", true)
+    force_experiment_result("signature display threshold", 0)
+    go_to petition_path(@petition)
+    element_exists(class: "progress_bar").should be_true
+  end
+
+  it "should not be visible" do
+    force_experiment_result("show thermometer", false)
+    force_experiment_result("signature display threshold", 0)
+    go_to petition_path(@petition)
+    element_exists(class: "progress_bar").should be_false
+  end
+
+  def force_experiment_result(name, value)
+    go_to "whiplash_sessions"
+    type(value).into(name: name)
+    click name: "commit"
+  end
+end