expose wether exception cause is supported

Author: JonRowe

lib/rspec/support/ruby_features.rb

@@ -55,6 +55,16 @@ def caller_locations_supported?
         respond_to?(:caller_locations, true)
       end
 
+      if Exception.method_defined?(:cause)
+        def supports_exception_cause?
+          true
+        end
+      else
+        def supports_exception_cause?
+          false
+        end
+      end
+
       if Ruby.mri?
         def kw_args_supported?
           RUBY_VERSION >= '2.0.0'

spec/rspec/support/ruby_features_spec.rb

@@ -59,6 +59,10 @@ module Support
     end
 
     describe RubyFeatures do
+      specify "#supports_exception_cause? exists" do
+        RubyFeatures.supports_exception_cause?
+      end
+
       specify "#kw_args_supported? exists" do
         RubyFeatures.kw_args_supported?
       end