Refactor implementation to use accessor for headers, avoiding crash

lib/csv-safe.rb

@@ -49,13 +49,10 @@ def sanitize_field(field)
   end
 
   def sanitize_row(row)
-    case row
-    when self.class::Row
-      then row.fields.map { |field| sanitize_field(field) }
-    when Hash
-      then @headers.map { |header| sanitize_field(row[header]) }
-    else
-      row.map { |field| sanitize_field(field) }
-    end
+    return row.fields.map { |field| sanitize_field(field) } if row.is_a?(self.class::Row)
+
+    return headers.map { |header| sanitize_field(row[header]) } if row.is_a?(Hash) && !headers.nil?
+
+    row.map { |field| sanitize_field(field) }
   end
 end

spec/csv_safe_spec.rb

@@ -122,12 +122,12 @@ def self.to_s
     end
 
     describe '#sanitize_row' do
-      before(:all) do
-        CSV_Instance = CSVSafe.new('')
-      end
-      subject { CSV_Instance.send(:sanitize_row, row) }
-
       context 'when the row is a CSV::Row' do
+        before(:all) do
+          CSV_Instance = CSVSafe.new('')
+        end
+        subject { CSV_Instance.send(:sanitize_row, row) }
+
         context "when the fields don't require sanitization" do
           let(:fields) { %w[Jane 30] }
           let(:row) { CSV::Row.new(%w[Name Age], fields) }
@@ -143,9 +143,11 @@ def self.to_s
       end
 
       context 'when the row is a Hash' do
-        before do
-          CSV_Instance.instance_variable_set(:@headers, %i[Name Age])
+        before(:all) do
+          CSV_Instance = CSVSafe.new('', headers: %i[Name Age])
         end
+        subject { CSV_Instance.send(:sanitize_row, row) }
+
         context "when the fields don't require sanitization" do
           let(:row) { { Name: 'Jane', Age: '30' } }
           let(:expected) { %w[Jane 30] }
@@ -158,9 +160,23 @@ def self.to_s
 
           it { should eq expected }
         end
+
+        it "does not crash" do
+          headers = %i[a b c]
+          payload = { b: :b, a: :a, c: :c }
+
+          output = CSVSafe.generate(headers: true) { |csv| csv << headers; csv << payload }.split "\n"
+
+          expect(output).to eq(["a,b,c", "a,b,c"])
+        end
       end
 
       context 'when the row is an array' do
+        before(:all) do
+          CSV_Instance = CSVSafe.new('')
+        end
+        subject { CSV_Instance.send(:sanitize_row, row) }
+
         context "when the fields don't require sanitization" do
           let(:row) { %w[Jane 30] }
           it { should eq row }