Fix map_headers when headers have the same prefix (#1598)

* Add test case for headers with same prefix when using map_headers

* Fix map_headers when multiple headers with same prefix

* Update changelog

* Use match? instead of match.nil?

Co-authored-by: Aurélien Reeves <aurelien.reeves@smartbear.com>

CHANGELOG.md

@@ -32,6 +32,10 @@ Please visit [cucumber/CONTRIBUTING.md](https://github.com/cucumber/cucumber/blo
   ([PR#1589](https://github.com/cucumber/cucumber-ruby/pull/1589)
    [Issue#1583](https://github.com/cucumber/cucumber-ruby/issues/1583))
 
+- Fixed `DataTable#map_headers` when headers have the same prefix.
+  ([PR#1598](https://github.com/cucumber/cucumber-ruby/pull/1598)
+   [Issue#1450](https://github.com/cucumber/cucumber-ruby/issues/1450))
+
 ### Changed
 
 - In `DataTable#map_column`, Changed the `strict` argument into a keyword argument.

lib/cucumber/multiline_argument/data_table.rb

@@ -492,7 +492,7 @@ def convert_headers! # :nodoc:
         end
 
         @header_mappings.each_pair do |pre, post|
-          mapped_cells = header_cells.reject { |cell| cell.value.match(pre).nil? }
+          mapped_cells = header_cells.select { |cell| pre.is_a?(Regexp) ? cell.value.match?(pre) : cell.value == pre }
           raise "No headers matched #{pre.inspect}" if mapped_cells.empty?
           raise "#{mapped_cells.length} headers matched #{pre.inspect}: #{mapped_cells.map(&:value).inspect}" if mapped_cells.length > 1
 

spec/cucumber/multiline_argument/data_table_spec.rb

@@ -169,7 +169,7 @@ module MultilineArgument
       describe '#map_headers' do
         let(:table) do
           DataTable.from([
-                           %w[HELLO WORLD],
+                           %w[ANT ANTEATER],
                            %w[4444 55555]
                          ])
         end
@@ -193,13 +193,13 @@ module MultilineArgument
         it 'takes a block and operates on all the headers with it' do
           table2 = table.map_headers(&:downcase)
 
-          expect(table2.hashes.first.keys).to match %w[hello world]
+          expect(table2.hashes.first.keys).to match %w[ant anteater]
         end
 
         it 'treats the mappings in the provided hash as overrides when used with a block' do
-          table2 = table.map_headers('WORLD' => 'foo', &:downcase)
+          table2 = table.map_headers('ANT' => 'foo', &:downcase)
 
-          expect(table2.hashes.first.keys).to match %w[hello foo]
+          expect(table2.hashes.first.keys).to match %w[foo anteater]
         end
       end