[patch:lib] Handle nil query results (#45)

* Handle nil query results

* Add coverage directory to .gitignore

* Remove coverage files

.gitignore

@@ -3,6 +3,7 @@
 /pkg/
 /spec/tmp/
 /tmp/
+/coverage/
 
 ## Used by dotenv library to load environment variables
 .env

lib/arx.rb

@@ -65,6 +65,12 @@ def search(*ids, query: nil, sort_by: :relevance, sort_order: :descending)
         raise Error::MissingPaper.new(ids.first) if results.title.empty?
       elsif results.is_a? Array
         results.reject! {|paper| paper.title.empty?}
+      elsif results.nil?
+        if ids.size == 1
+          raise Error::MissingPaper.new(ids.first)
+        else
+          results = []
+        end
       end
 
       results

spec/arx/arx_spec.rb

@@ -31,6 +31,9 @@
         it { is_expected.to be_a Paper }
         it { is_expected.to get_paper papers.first }
       end
+      context '(valid restricted)' do
+        it { expect { Arx.search('1809.09415') {|q| q.title 'bob'} }.to raise_error Error::MissingPaper }
+      end
       context '(valid URL)' do
         subject { Arx.search 'https://arxiv.org/abs/1105.5379' }
 
@@ -39,6 +42,8 @@
       end
       context '(invalid)' do
         it { expect { Arx.search '1234.1234' }.to raise_error Error::MissingPaper }
+        it { expect { Arx.search '1809.0000' }.to raise_error Error::MissingPaper }
+        it { expect { Arx.search '1809.00000' }.to raise_error Error::MissingPaper }
       end
       context '(invalid format)' do
         it { expect { Arx.search 'abc' }.to raise_error ArgumentError }
@@ -52,6 +57,9 @@
         it { is_expected.to all be_a Paper }
         it { is_expected.to get_papers papers }
       end
+      context '(valid restricted)' do
+        it { expect(Arx.search('1809.09415', 'cond-mat/9609089') {|q| q.title 'bob'}).to eq [] }
+      end
       context '(invalid)' do
         it { expect { Arx.search '1234.1234', 'invalid-category/1234567' }.to raise_error ArgumentError }
       end