Improve readability

services/importer/lib/importer/loader.rb

@@ -292,12 +292,12 @@ module CartoDB
       # Sometimes we could try to recover from a known failure
       def try_fallback(append_mode)
         if ogr2ogr.invalid_dates?
-          job.log "Fallback: Disabling autoguessing because there are wrong dates in the source file"
+          job.log "Fallback: Autoguessing problem, trying to disable the problematic column"
           @job.fallback_executed = "date"
           ogr2ogr.overwrite = true
           ogr2ogr.csv_guessing = true
           ogr2ogr.quoted_fields_guessing = false
-          try_fix_invalid_field(ogr2ogr.filepath, ogr2ogr.command_output)
+          disable_autoguessing_on_wrong_column(ogr2ogr.filepath, ogr2ogr.command_output)
           ogr2ogr.run(append_mode)
         elsif ogr2ogr.encoding_error?
           job.log "Fallback: There is an encoding problem, trying with ISO-8859-1"
@@ -388,9 +388,9 @@ module CartoDB
         error =~ /canceling statement due to statement timeout/i
       end
 
-      def try_fix_invalid_field(filepath, command_output)
-        line = command_output.split('line')[1].split(':')[0].split(',')[0].delete(' ').to_i - 1
-        column = command_output.split('column')[1].split(':')[0].split(',')[0].delete(' ')
+      def disable_autoguessing_on_wrong_column(filepath, command_output)
+        line = /(?<=, line )\d+(?=,)/.match(command_output).to_s.to_i - 1
+        column = /(?<=, column )[a-zA-Z]+(?=:)/.match(command_output).to_s.strip()
         csv_content = CSV.read(filepath, headers: true)
         csv_content[line][column] = "\"#{csv_content[line][column]}\""
         File.open(filepath, 'w') { |file| file.puts csv_content.to_s }

services/importer/spec/acceptance/csv_spec.rb

@@ -377,7 +377,7 @@ describe 'csv regression tests' do
     runner.results.first.success?.should eq true
   end
 
-  it 'auto guessing should work in csv columns if one field is causing troubles' do
+  it 'should autoguess columns type correctly when the CSV contains invalid field values' do
     runner = runner_with_fixture('wrong_date_auto_guessing.csv', nil, true)
     runner.run
 
@@ -387,7 +387,7 @@ describe 'csv regression tests' do
       from #{result.schema}.#{result.table_name}
       }].first.fetch(:age)
 
-    age.class.should eq Integer
+    expect(age).to be_an(Integer)
   end
 
   def sample_for(job)

services/importer/spec/fixtures/wrong_date_auto_guessing.csv

@@ -1,12 +1,3 @@
 age,date,name
 20,2000-01-01,name_1
-21,2000-01-01,name_2
 22,2000-1-NA,name_3
-23,2000-01-01,name_4
-24,2000-1-NA,name_5
-25,2000-01-01,name_6
-26,2000-1-NA,name_7
-27,2000-01-01,name_8
-28,2000-01-01,name_9
-29,2000-1-NA,name_10
-30,2000-01-01,name_11