add model validation error reporting

lib/excelsior/error.rb

+module Excelsior
+  Error = Struct.new(:row, :errors)
+end

lib/excelsior/import.rb

@@ -3,6 +3,7 @@ require 'rails'
 require 'active_record'
 require 'excelsior/source'
 require 'excelsior/mapping'
+require 'excelsior/error'
 
 module Excelsior
   class Import
@@ -26,12 +27,13 @@ module Excelsior
     end
 
     def run # takes an optional block
-      @rows.map do |row|
+      @rows.map.with_index do |row, i|
         attributes = map_row_values(row, @columns)
         if block_given?
           yield attributes
         else
-          model_class.create!(attributes)
+          record = model_class.create(attributes)
+          add_model_errors(record, i)
         end
       end
     end
@@ -52,5 +54,13 @@ module Excelsior
     def model_class
       self.class.name.gsub("Import", "").constantize
     end
+
+    def add_model_errors(record, index)
+      return if record.errors.empty?
+
+      @errors[:model] ||= []
+
+      @errors[:model] << Error.new(index + 1, record.errors.full_messages)
+    end
   end
 end

test/excelsior_test.rb

@@ -15,6 +15,7 @@ end
 
 class ExcelsiorTest < Minitest::Test
   def setup
+    User.delete_all
     @import = UserImport.new
   end
 
@@ -74,4 +75,10 @@ class ExcelsiorTest < Minitest::Test
     import = UserImport.new("test/files/missing-column.xlsx")
     assert import.errors[:missing_column].any?
   end
+
+  def test_model_validations
+    import = UserImport.new("test/files/missing-first-name.xlsx").tap(&:run)
+    assert import.errors[:model].any?
+    assert_equal import.errors[:model], [Excelsior::Error.new(3, ["First name can't be blank"])]
+  end
 end