Update more rspec old style .should calls

spec/alternative_spec.rb

@@ -206,11 +206,11 @@
     end
 
     it "should have a probability of being the winning alternative (p_winner)" do
-      alternative.p_winner.should_not be_nil
+      expect(alternative.p_winner).not_to be_nil
     end
 
     it "should have a probability of being the winner for each goal" do
-      alternative.p_winner(goal1).should_not be_nil
+      expect(alternative.p_winner(goal1)).not_to be_nil
     end
 
     it "should be possible to set the p_winner" do

spec/encapsulated_helper_spec.rb

@@ -18,7 +18,7 @@ def params
 
   describe "ab_test" do
     it "should not raise an error when params raises an error" do
-      lambda { ab_test('link_color', 'blue', 'red') }.should_not raise_error
+      expect(lambda { ab_test('link_color', 'blue', 'red') }).not_to raise_error
     end
   end
 end

spec/experiment_spec.rb

@@ -381,13 +381,13 @@ def same_but_different_goals
     it "should return a hash with the probability of each alternative being the best" do
       experiment = Split::Experiment.find_or_create('mathematicians', 'bernoulli', 'poisson', 'lagrange')
       experiment.calc_winning_alternatives
-      experiment.alternative_probabilities.should_not be_nil
+      expect(experiment.alternative_probabilities).not_to be_nil
     end
 
     it "should return between 46% and 54% probability for an experiment with 2 alternatives and no data" do
       experiment = Split::Experiment.find_or_create('scientists', 'einstein', 'bohr')
       experiment.calc_winning_alternatives
-      experiment.alternatives[0].p_winner.should be_within(0.04).of(0.50)
+      expect(experiment.alternatives[0].p_winner).to be_within(0.04).of(0.50)
     end
 
     it "should calculate the probability of being the winning alternative separately for each goal" do
@@ -403,8 +403,8 @@ def same_but_different_goals
       alt = experiment.alternatives[0]
       p_goal1 = alt.p_winner(goal1)
       p_goal2 = alt.p_winner(goal2)
-      p_goal1.should_not be_within(0.04).of(p_goal2)
+      expect(p_goal1).not_to be_within(0.04).of(p_goal2)
     end
-  end 
+  end
 
 end