Fix failing tests

Author: izuzak

test/scientist/experiment_test.rb

@@ -181,7 +181,7 @@ def @ex.publish(result)
   end
 
   it "compares errors with an error comparator block if provided" do
-    @ex.error_compare { |a, b| a.class == b.class }
+    @ex.compare_errors { |a, b| a.class == b.class }
     @ex.use { raise "foo" }
     @ex.try { raise "bar" }
 

test/scientist/observation_test.rb

@@ -97,14 +97,19 @@
     b = Scientist::Observation.new("test", @experiment) { "1" }
 
     refute a.equivalent_to?(b)
-    assert a.equivalent_to?(b) { |x, y| x.to_s == y.to_s }
+
+    compare_on_string = -> (x, y) { x.to_s == y.to_s }
+
+    assert a.equivalent_to?(b, compare_on_string)
 
     yielded = []
-    a.equivalent_to?(b) do |x, y|
+    compare_appends = -> (x, y) do
       yielded << x
       yielded << y
       true
     end
+    a.equivalent_to?(b, compare_appends)
+
     assert_equal [a.value, b.value], yielded
   end