diff --git a/lib/datagrid/drivers/abstract_driver.rb b/lib/datagrid/drivers/abstract_driver.rb
index 6125e532..8cf5e6bc 100644
--- a/lib/datagrid/drivers/abstract_driver.rb
+++ b/lib/datagrid/drivers/abstract_driver.rb
@@ -63,7 +63,7 @@ def reverse_order(scope)
         raise NotImplementedError
       end
 
-      def is_timestamp?(scope, field)
+      def timestamp_column?(scope, field)
         normalized_column_type(scope, field) == :timestamp
       end
 
diff --git a/lib/datagrid/drivers/mongo_mapper.rb b/lib/datagrid/drivers/mongo_mapper.rb
index 48871ac8..b0a7738a 100644
--- a/lib/datagrid/drivers/mongo_mapper.rb
+++ b/lib/datagrid/drivers/mongo_mapper.rb
@@ -46,7 +46,7 @@ def scope_has_column?(scope, column_name)
         scope.key?(column_name)
       end
 
-      def is_timestamp?(_scope, _column_name)
+      def timestamp_column?(_scope, _column_name)
         # TODO: implement the support
         false
       end
diff --git a/lib/datagrid/filters/date_filter.rb b/lib/datagrid/filters/date_filter.rb
index 2a7d29d8..12057178 100644
--- a/lib/datagrid/filters/date_filter.rb
+++ b/lib/datagrid/filters/date_filter.rb
@@ -25,7 +25,7 @@ def format(value)
       end
 
       def default_filter_where(scope, value)
-        value = Datagrid::Utils.format_date_as_timestamp(value) if driver.is_timestamp?(scope, name)
+        value = Datagrid::Utils.format_date_as_timestamp(value) if driver.timestamp_column?(scope, name)
         super
       end
 
diff --git a/lib/datagrid/filters/dynamic_filter.rb b/lib/datagrid/filters/dynamic_filter.rb
index 77e922b5..7487ab8a 100644
--- a/lib/datagrid/filters/dynamic_filter.rb
+++ b/lib/datagrid/filters/dynamic_filter.rb
@@ -41,7 +41,7 @@ def unapplicable_value?(filter)
 
       def default_filter_where(scope, filter)
         field, operation, value = filter
-        date_conversion = value.is_a?(Date) && driver.is_timestamp?(scope, field)
+        date_conversion = value.is_a?(Date) && driver.timestamp_column?(scope, field)
 
         return scope if field.blank? || operation.blank?
 
diff --git a/lib/datagrid/utils.rb b/lib/datagrid/utils.rb
index 3a2a18dd..e1142ae4 100644
--- a/lib/datagrid/utils.rb
+++ b/lib/datagrid/utils.rb
@@ -79,6 +79,7 @@ def parse_date(value)
           Array(Datagrid.configuration.date_formats).each do |format|
             return Date.strptime(value, format)
           rescue ::ArgumentError
+            nil
           end
         end
         return Date.parse(value) if value.is_a?(String)
@@ -97,6 +98,7 @@ def parse_datetime(value)
           Array(Datagrid.configuration.datetime_formats).each do |format|
             return Time.strptime(value, format)
           rescue ::ArgumentError
+            nil
           end
         end
         return Time.parse(value) if value.is_a?(String)
diff --git a/spec/datagrid/filters/boolean_filter_spec.rb b/spec/datagrid/filters/boolean_filter_spec.rb
index 96ed6cdf..4b10491c 100644
--- a/spec/datagrid/filters/boolean_filter_spec.rb
+++ b/spec/datagrid/filters/boolean_filter_spec.rb
@@ -1,4 +1,6 @@
-require 'spec_helper'
+# frozen_string_literal: true
+
+require "spec_helper"
 
 describe Datagrid::Filters::BooleanFilter do
   it "applies default filtering" do
diff --git a/spec/datagrid/filters_spec.rb b/spec/datagrid/filters_spec.rb
index 203ba29f..1d390f73 100644
--- a/spec/datagrid/filters_spec.rb
+++ b/spec/datagrid/filters_spec.rb
@@ -304,16 +304,16 @@ class TestGrid8728
     end
 
     context "with delegation to attribute" do
-      let(:role) { OpenStruct.new("admin?" => admin) }
+      let(:role) { Struct.new(:admin).new(admin) }
       let(:klass) do
         test_report_class do
           attr_accessor :role
 
-          delegate :admin?, to: :role
+          delegate :admin, to: :role
 
           scope { Entry }
 
-          filter(:id, :integer, if: :admin?)
+          filter(:id, :integer, if: :admin)
         end
       end
 
diff --git a/spec/datagrid/helper_spec.rb b/spec/datagrid/helper_spec.rb
index a4660b53..1685d525 100644
--- a/spec/datagrid/helper_spec.rb
+++ b/spec/datagrid/helper_spec.rb
@@ -483,15 +483,15 @@ class FormForGrid
       end
       object = FormForGrid.new(category: "hello")
       expect(subject.datagrid_form_for(object, url: "/grid")).to equal_to_dom(<<~HTML)
- <form class="datagrid-form form_for_grid" id="new_form_for_grid" action="/grid" accept-charset="UTF-8" method="get">    <div class="datagrid-filter filter">
-      <label for="form_for_grid_category">Category</label>
-      <input value="hello" class="category default_filter" type="text" name="form_for_grid[category]" id="form_for_grid_category" />
-    </div>
-  <div class="datagrid-actions">
-    <input type="submit" name="commit" value="Search" class="datagrid-submit" data-disable-with="Search" />
-    <a class="datagrid-reset" href="/location">Reset</a>
-  </div>
-</form>
+         <form class="datagrid-form form_for_grid" id="new_form_for_grid" action="/grid" accept-charset="UTF-8" method="get">    <div class="datagrid-filter filter">
+              <label for="form_for_grid_category">Category</label>
+              <input value="hello" class="category default_filter" type="text" name="form_for_grid[category]" id="form_for_grid_category" />
+            </div>
+          <div class="datagrid-actions">
+            <input type="submit" name="commit" value="Search" class="datagrid-submit" data-disable-with="Search" />
+            <a class="datagrid-reset" href="/location">Reset</a>
+          </div>
+        </form>
       HTML
     end
     it "should support html classes for grid class with namespace" do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index fed002fd..4c60b72d 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -21,13 +21,10 @@
 begin
   require "mongo_mapper"
 rescue LoadError
+  nil
 end
 
 require "datagrid"
-begin
-  require "ruby-debug"
-rescue LoadError
-end
 require "rspec"
 require "logger"