fix parsing endless range values (#896)

Author: dhruvCW

CHANGELOG.md

@@ -5,6 +5,7 @@
 * Your contribution here.
 
 #### Fixes
+* [#868](https://github.com/ruby-grape/grape-swagger/pull/896): Fix parsing endless range values - [@dhruvCW](https://github.com/dhruvCW)
 
 * Your contribution here.
 

lib/grape-swagger/doc_methods/parse_params.rb

@@ -171,7 +171,7 @@ def parse_enum_or_range_values(values)
         end
 
         def parse_range_values(values)
-          { minimum: values.first, maximum: values.last }
+          { minimum: values.begin, maximum: values.end }.compact
         end
       end
     end

spec/lib/parse_params_spec.rb

@@ -12,6 +12,20 @@
       parsed_range = subject.send(:parse_range_values, start_value..end_value)
       expect(parsed_range).to eql(minimum: start_value, maximum: end_value)
     end
+
+    describe 'endless range' do
+      specify do
+        parsed_range = subject.send(:parse_range_values, start_value..)
+        expect(parsed_range).to eql(minimum: start_value)
+      end
+    end
+
+    describe 'beginless range' do
+      specify do
+        parsed_range = subject.send(:parse_range_values, ..end_value)
+        expect(parsed_range).to eql(maximum: end_value)
+      end
+    end
   end
 
   describe '#parse_enum_or_range_values' do