lib/matchete.rb in matchete-0.4.0 vs lib/matchete.rb in matchete-0.5.0

@@ -31,20 +31,28 @@
       @default_methods[method_name] = instance_method(method_name)
       convert_to_matcher method_name
     end
 
     # Matches something like sum types:
-    # either(Integer, Array) 
+    # either(Integer, Array)
     # matches both [2] and 2
     def either(*guards)
       -> arg { guards.any? { |g| match_guard(g, arg) } }
     end
 
     # Matches an exact value
     # useful if you want to match a string starting with '#' or the value of a class
     # exact(Integer) matches Integer, not 2
     def exact(value)
       -> arg { arg == value }
+    end
+
+    # Matches property results
+    # e.g. having('#to_s': '[]') will match []
+    def having(**properties)
+      -> arg do
+        properties.all? { |prop, result| arg.respond_to?(prop[1..-1]) && arg.send(prop[1..-1]) == result }
+      end
     end
 
     # Matches each guard
     # full_match(Integer, '#value')
     # matches only instances of Integer which respond to '#value'