Merge pull request rails#54615 from yahonda/assert_nil_if_expecting_nil_is_deprecated

Enable `Minitest/AssertNil` cop to address `DEPRECATED: Use assert_nil if expecting nil` warning

Author: yahonda

.rubocop.yml

@@ -384,6 +384,9 @@ Performance/RedundantStringChars:
 Performance/StringInclude:
   Enabled: true
 
+Minitest/AssertNil:
+  Enabled: true
+
 Minitest/AssertPredicate:
   Enabled: true
 

actionpack/test/controller/integration_test.rb

@@ -495,7 +495,7 @@ def test_post_then_get_with_parameters_do_not_leak_across_requests
       assert_equal "foo=bar", request.env["QUERY_STRING"]
       assert_equal "foo=bar", request.query_string
       assert_equal "bar", request.parameters["foo"]
-      assert_predicate request.parameters["leaks"], :nil?
+      assert_nil request.parameters["leaks"]
     end
   end
 

actiontext/test/unit/model_test.rb

@@ -18,7 +18,7 @@ class ActionText::ModelTest < ActiveSupport::TestCase
   test "without content" do
     assert_difference("ActionText::RichText.count" => 0) do
       message = Message.create!(subject: "Greetings")
-      assert_predicate message.content, :nil?
+      assert_nil message.content
       assert_predicate message.content, :blank?
       assert_predicate message.content, :empty?
       assert_not message.content?
@@ -146,7 +146,7 @@ class ActionText::ModelTest < ActiveSupport::TestCase
   test "with blank content and store_if_blank: false" do
     assert_difference("ActionText::RichText.count" => 0) do
       message = MessageWithoutBlanks.create!(subject: "Greetings", content: "")
-      assert_predicate message.content, :nil?
+      assert_nil message.content
       assert_predicate message.content, :blank?
       assert_predicate message.content, :empty?
       assert_not message.content?

activemodel/test/cases/type/boolean_test.rb

@@ -7,8 +7,8 @@ module Type
     class BooleanTest < ActiveModel::TestCase
       def test_type_cast_boolean
         type = Type::Boolean.new
-        assert_predicate type.cast(""), :nil?
-        assert_predicate type.cast(nil), :nil?
+        assert_nil type.cast("")
+        assert_nil type.cast(nil)
 
         assert type.cast(true)
         assert type.cast(1)

activemodel/test/cases/validations_test.rb

@@ -252,7 +252,7 @@ def test_validation_with_if_and_on
 
     # If block should not fire
     assert_predicate t, :valid?
-    assert_predicate t.author_name, :nil?
+    assert_nil t.author_name
 
     # If block should fire
     assert t.invalid?(:update)

activerecord/test/cases/associations/has_many_through_associations_test.rb

@@ -1243,7 +1243,7 @@ def test_deleting_from_has_many_through_a_belongs_to_should_not_try_to_update_co
 
     assert_includes post.author_addresses, address
     post.author_addresses.delete(address)
-    assert_predicate post[:author_count], :nil?
+    assert_nil post[:author_count]
   end
 
   def test_primary_key_option_on_source

railties/test/application/configuration_test.rb

@@ -4028,7 +4028,7 @@ class Post < ActiveRecord::Base
 
       app "development"
 
-      assert_equal nil, ActiveStorage.variant_processor
+      assert_nil ActiveStorage.variant_processor
     end
 
     test "ActiveStorage.variant_processor uses vips by default" do