Make csv import columns order independant from the column definitions

lib/csvbuilder/importer/concerns/import/attributes.rb

@@ -30,16 +30,17 @@ def attribute_objects
       end
 
       def read_attribute_for_validation(attr)
-        source_row[self.class.column_names.index(attr)]
+        attr_index = source_headers.index(column_header(attr))
+        return source_row[attr_index] unless attr_index.nil?
+
+        nil
       end
 
       protected
 
       def _attribute_objects
-        index = -1
-
-        array_to_block_hash(self.class.column_names) do |column_name|
-          Attribute.new(column_name, source_row[index += 1], errors.to_hash[column_name], self)
+        self.class.column_names.to_h do |column_name|
+          [column_name, Attribute.new(column_name, read_attribute_for_validation(column_name), errors.to_hash[column_name], self)]
         end
       end
 

lib/csvbuilder/importer/concerns/import/base.rb

@@ -25,7 +25,13 @@ def initialize(source_row_or_exception = [], options = {})
 
         @line_number    = options[:line_number]
         @index          = options[:index]
-        @source_headers = options[:source_headers]
+        # options[:source_headers] can be an Exception or nil
+        @source_headers = case options[:source_headers]
+                          in Array
+                            options[:source_headers]
+                          else
+                            []
+                          end
 
         @previous       = options[:previous].try(:dup)
 

spec/csvbuilder/importer/concerns/import/attributes_spec.rb

@@ -7,7 +7,7 @@ module Import
     RSpec.describe Attributes do
       let(:row_model_class) { Class.new BasicImportModel }
       let(:source_row)      { %w[alpha beta] }
-      let(:options)         { { foo: :bar } }
+      let(:options)         { { foo: :bar, source_headers: ["Alpha", "Beta Two"] } }
       let(:instance)        { row_model_class.new(source_row, options) }
 
       describe "instance" do
@@ -21,6 +21,11 @@ module Import
           it "returns a hash of cells mapped to their column_name" do
             expect(attribute_objects.keys).to eql row_model_class.column_names
             expect(attribute_objects.values.map(&:class)).to eql [Csvbuilder::Import::Attribute] * 2
+
+            # ensure that attributes are correctly set
+            {alpha: "alpha", beta: "beta"}.each do |attr, value|
+              expect(attribute_objects[attr].value).to eql value
+            end
           end
 
           context "when invalid" do

spec/csvbuilder/importer/concerns/import/base_spec.rb

@@ -7,7 +7,8 @@ module Import
     RSpec.describe Base do
       describe "instance" do
         let(:source_row)      { %w[alpha beta] }
-        let(:options)         { {} }
+        let(:source_headers)  { { source_headers: ["Alpha", "Beta Two"] } }
+        let(:options)         { source_headers }
         let(:row_model_class) { BasicImportModel }
         let(:instance)        { row_model_class.new(source_row, options) }
 
@@ -40,7 +41,7 @@ module Import
         describe "#free_previous" do
           subject(:free_previous) { instance.free_previous }
 
-          let(:options) { { previous: row_model_class.new([]) } }
+          let(:options) { { previous: row_model_class.new([], source_headers), **source_headers } }
 
           it "makes previous nil" do
             expect { free_previous }.to change(instance, :previous).to(nil)
@@ -56,9 +57,12 @@ def alpha
             end
             let(:source_row) { [] }
             let(:options) do
-              { previous: row_model_class.new([],
+              {
+                previous: row_model_class.new([],
                                               previous: row_model_class.new(["alpha from previous > previous",
-                                                                             "beta"])) }
+                                                                             "beta"], source_headers), **source_headers),
+                **source_headers
+              }
             end
 
             it "grabs alpha from previous.previous" do

spec/csvbuilder/importer/concerns/import/csv_string_model_spec.rb

@@ -5,8 +5,7 @@
 RSpec.describe "Csvbuilder::Import::ParsedModel" do
   describe "instance" do
     let(:source_row) { %w[alpha beta] }
-    let(:options)    { { foo: :bar } }
-    let(:klass)      { BasicImportModel }
+    let(:options)    { { foo: :bar, source_headers: ["Id"] } }
     let(:instance)   { klass.new(source_row, options) }
 
     describe "#valid?" do

spec/csvbuilder/importer/public/import_spec.rb

@@ -15,7 +15,8 @@ module Csvbuilder
       end
 
       it do
-        expect(klass.new(%w[alpha beta]).attributes).to eql(alpha: "alpha", beta: "beta")
+        instance = klass.new(%w[alpha beta], source_headers: ["Alpha", "Beta"])
+        expect(instance.attributes).to eql(alpha: "alpha", beta: "beta")
       end
 
       it "has Csvbuilder::Model included" do

spec/support/shared_examples/methods/column_method.rb

@@ -8,7 +8,7 @@
       row_model_class.send(:include, Csvbuilder::Model)
       row_model_class.send(:column, :alpha)
       row_model_class.send(:include, mod)
-      row_model_class.send(:column, :beta)
+      row_model_class.send(:column, :beta, header: "Beta Two")
     end
 
     it do