Extract SelectInput and CheckboxInput

Both are subclasses of `ArrayInput`. Now, `ArrayInput#fill` chains together
successive calls to `SelectInput#fill` and `CheckboxInput#fill`, finally failing
with an informative exception if neither inputs exist on the page.

Author: seanpdoyle

README.md

@@ -150,7 +150,7 @@ around `I18n.t`.
   | `Date`, `ActiveSupport::TimeWithZone` | `select` year, month, and day    |
   | `TrueClass`                           | `check`                          |
   | `FalseClass`                          | `uncheck`                        |
-  | `Array`                               | `check` or `select` each array member, which should all be strings |
+  | `Array`                               | `check` or `select` each array member, which should all be strings. If not all items can be selected or checked, an error will be thrown.|
   | `File`                                | `attach_file` with `File#path`   |
 
 * Formulaic is currently tied to `simple_form` translations and field structure.

lib/formulaic/inputs/array_input.rb

@@ -7,49 +7,34 @@ def initialize(label, value)
       end
 
       def fill
-        if has_select?
-          select_options
-        elsif has_check_boxes?
-          check_boxes
-        else
-          raise InputNotFound.new(%[Unable to find checkboxes or select[multiple] "#{label}" containing all options #{value.inspect}.])
-        end
+        attempt_to_fill_selects ||
+          attempt_to_fill_checkboxes ||
+          raise_input_error
       end
 
       private
 
-      def has_select?
-        has_field?(label, type: "select") &&
-          begin
-            select = find_field(label, type: "select")
-            select[:multiple].present? &&
-              contains_all_options?(select.all("option"))
-          end
+      def attempt_to_fill_selects
+        SelectInput.new(label, value).fill
       end
 
-      def has_check_boxes?
-        checkbox_name_selector =
-          "input[type='checkbox']" \
-          "[name='#{label.model_name}[#{label.attribute}][]']"
-        check_box_labels =
-          all(
-            "#{checkbox_name_selector} ~ label," \
-            "label:has(#{checkbox_name_selector})"
-          ).to_a.flatten
-        contains_all_options?(check_box_labels)
-      end
-
-      def select_options
-        value.each { |option| select option, from: label.to_str }
-      end
-
-      def check_boxes
-        value.each { |checkbox| check checkbox }
+      def attempt_to_fill_checkboxes
+        CheckboxInput.new(label, value).fill
       end
 
       def contains_all_options?(nodes)
         nodes.map(&:text).to_set.superset?(value.to_set)
       end
+
+      def raise_input_error
+        raise(
+          InputNotFound,
+          %[Unable to find checkboxes or select[multiple] "#{label}" containing all options #{value.inspect}.]
+        )
+      end
     end
   end
 end
+
+require 'formulaic/inputs/checkbox_input'
+require 'formulaic/inputs/select_input'

lib/formulaic/inputs/checkbox_input.rb

@@ -0,0 +1,36 @@
+module Formulaic
+  module Inputs
+    class CheckboxInput < ArrayInput
+      def fill
+        if has_check_boxes?
+          check_boxes
+          true
+        else
+          false
+        end
+      end
+
+      private
+
+      def has_check_boxes?
+        contains_all_options?(checkbox_labels)
+      end
+
+      def check_boxes
+        value.each { |checkbox| check checkbox }
+      end
+
+      def checkbox_labels
+        all(
+          "#{checkbox_name_selector} ~ label," \
+          "label:has(#{checkbox_name_selector})"
+        )
+      end
+
+      def checkbox_name_selector
+        "input[type='checkbox']" \
+          "[name='#{label.model_name}[#{label.attribute}][]']"
+      end
+    end
+  end
+end

lib/formulaic/inputs/select_input.rb

@@ -0,0 +1,37 @@
+module Formulaic
+  module Inputs
+    class SelectInput < ArrayInput
+      def fill
+        if has_multiple_select?
+          select_options
+          true
+        else
+          false
+        end
+      end
+
+      private
+
+      def select_options
+        value.each { |option| select option, from: label.to_str }
+      end
+
+      def has_multiple_select?
+        has_select? && select_is_multiple?
+      end
+
+      def has_select?
+        has_field?(label, type: "select")
+      end
+
+      def select_is_multiple?
+        select_element[:multiple].present? &&
+          contains_all_options?(select_element.all("option"))
+      end
+
+      def select_element
+        @select_element ||= find_field(label, type: "select")
+      end
+    end
+  end
+end