Inherit raise_on_mismatches from the superclass

README.md

@@ -405,6 +405,8 @@ end
 MyExperiment.raise_on_mismatches = true
 ```
 
+Subclasses of `MyExperiment` inherit this setting unless they set their own.
+
 Scientist will raise a `Scientist::Experiment::MismatchError` exception if any observations don't match.
 
 #### Custom mismatch errors

lib/scientist/experiment.rb

@@ -72,8 +72,15 @@ def raise_on_mismatches=(bool)
     end
 
     # Whether or not to raise a mismatch error when a mismatch occurs.
+    #
+    # Subclasses inherit the setting from their superclass unless they set
+    # their own.
     def raise_on_mismatches?
-      @raise_on_mismatches
+      if !@raise_on_mismatches.nil?
+        @raise_on_mismatches
+      elsif respond_to?(:superclass) && superclass.respond_to?(:raise_on_mismatches?)
+        superclass.raise_on_mismatches?
+      end
     end
   end
 

test/scientist/experiment_test.rb

@@ -546,6 +546,29 @@ def @ex.raised(op, exception)
 
         assert_raises(Scientist::Experiment::MismatchError) { @ex.run }
       end
+
+      it "inherits the raise_on_mismatches class attribute from a superclass" do
+        subclass = Class.new(Fake)
+        Fake.raise_on_mismatches = true
+
+        ex = subclass.new
+        ex.use { "fine" }
+        ex.try { "not fine" }
+
+        assert_raises(Scientist::Experiment::MismatchError) { ex.run }
+      end
+
+      it "lets a subclass override the raise_on_mismatches class attribute" do
+        subclass = Class.new(Fake)
+        Fake.raise_on_mismatches = true
+        subclass.raise_on_mismatches = false
+
+        ex = subclass.new
+        ex.use { "fine" }
+        ex.try { "not fine" }
+
+        assert_equal "fine", ex.run
+      end
     end
 
     describe "MismatchError" do