Remove configuration to control what we do with tests without assertions

This is too much complexity for something low value. Let's just always
warn when a test doesn't have any assertions.

If people want to raise an error or ignore them, they can do so by
overriding `Warning.warn`.

activesupport/CHANGELOG.md

@@ -1,12 +1,8 @@
-*   Allow assertionless tests to be reported.
+*   Warn on tests without assertions.
 
-    `ActiveSupport::TestCase` can be configured to report tests that do not run any assertions.
+    `ActiveSupport::TestCase` now warns when tests do not run any assertions.
     This is helpful in detecting broken tests that do not perform intended assertions.
 
-    ```ruby
-    config.active_support.assertionless_tests_behavior = :raise
-    ```
-
     *fatkodima*
 
 *   Support `hexBinary` type in `ActiveSupport::XmlMini`.

activesupport/lib/active_support/railtie.rb

@@ -124,10 +124,6 @@ class Railtie < Rails::Railtie # :nodoc:
           ActiveSupport.deprecator.warn("config.active_support.remove_deprecated_time_with_zone_name is deprecated and will be removed in Rails 7.2.")
         elsif k == :use_rfc4122_namespaced_uuids
           ActiveSupport.deprecator.warn("config.active_support.use_rfc4122_namespaced_uuids is deprecated and will be removed in Rails 7.2.")
-        elsif k == :assertionless_tests_behavior
-          ActiveSupport.on_load(:active_support_test_case) do
-            ActiveSupport::TestCase.assertionless_tests_behavior = v
-          end
         else
           k = "#{k}="
           ActiveSupport.public_send(k, v) if ActiveSupport.respond_to? k

activesupport/lib/active_support/test_case.rb

@@ -3,7 +3,7 @@
 require "minitest"
 require "active_support/testing/tagged_logging"
 require "active_support/testing/setup_and_teardown"
-require "active_support/testing/assertionless_tests"
+require "active_support/testing/tests_without_assertions"
 require "active_support/testing/assertions"
 require "active_support/testing/error_reporter_assertions"
 require "active_support/testing/deprecation"
@@ -143,7 +143,7 @@ def parallelize_teardown(&block)
 
     include ActiveSupport::Testing::TaggedLogging
     prepend ActiveSupport::Testing::SetupAndTeardown
-    prepend ActiveSupport::Testing::AssertionlessTests
+    prepend ActiveSupport::Testing::TestsWithoutAssertions
     include ActiveSupport::Testing::Assertions
     include ActiveSupport::Testing::ErrorReporterAssertions
     include ActiveSupport::Testing::Deprecation

activesupport/lib/active_support/testing/tests_without_assertions.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module Testing
+    # Warns when a test case does not perform any assertions.
+    #
+    # This is helpful in detecting broken tests that do not perform intended assertions.
+    module TestsWithoutAssertions # :nodoc:
+      def after_teardown
+        super
+
+        return if skipped? || error?
+
+        if assertions == 0
+          file, line = method(name).source_location
+          message = "Test is missing assertions: `#{name}` #{file}:#{line}"
+          warn message
+        end
+      end
+    end
+  end
+end

activesupport/test/testing/test_without_assertions_test.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require_relative "../abstract_unit"
+require "active_support/core_ext/object/with"
+
+module TestsWithoutAssertionsTest
+  module Tests
+    def test_without_assertions
+    end
+  end
+
+  class TestsWithoutAssertionsWarnTest < ActiveSupport::TestCase
+    module AfterTeardown
+      def after_teardown
+        _out, err = capture_io do
+          super
+        end
+
+        assert_match(/Test is missing assertions: `test_without_assertions` .+test_without_assertions_test\.rb:\d+/, err)
+      end
+    end
+
+    include Tests
+    prepend AfterTeardown
+  end
+end

guides/source/configuring.md

@@ -64,7 +64,6 @@ Below are the default values associated with each target version. In cases of co
 - [`config.active_record.automatically_invert_plural_associations`](#config-active-record-automatically-invert-plural-associations): `true`
 - [`config.active_record.validate_migration_timestamps`](#config-active-record-validate-migration-timestamps): `true`
 - [`config.active_storage.web_image_content_types`](#config-active-storage-web-image-content-types): `%w[image/png image/jpeg image/gif image/webp]`
-- [`config.active_support.assertionless_tests_behavior`](#config-active-support-assertionless-tests-behavior): `:log`
 
 #### Default Values for Target Version 7.1
 
@@ -2657,18 +2656,6 @@ The default value depends on the `config.load_defaults` target version:
 | (original)            | `false`              |
 | 7.0                   | `true`               |
 
-#### `config.active_support.assertionless_tests_behavior`
-
-Controls the behavior when a test do not run any assertions. The following options are available:
-
-  * `:ignore` - Assertionless tests will be ignored. This is the default.
-
-  * `:log` - Assertionless tests will be logged via `Rails.logger` at the `:warn` level.
-
-  * `:raise` - Assertionless tests will be considered as failed and raise an error.
-
-  * Custom proc - A custom proc can be provided. It should accept an error message.
-
 #### `ActiveSupport::Logger.silencer`
 
 Is set to `false` to disable the ability to silence logging in a block. The default is `true`.

railties/lib/rails/application/configuration.rb

@@ -334,12 +334,6 @@ def load_defaults(target_version)
             active_record.validate_migration_timestamps = true
             active_record.automatically_invert_plural_associations = true
           end
-
-          if respond_to?(:active_support)
-            if Rails.env.local?
-              active_support.assertionless_tests_behavior = :log
-            end
-          end
         else
           raise "Unknown version #{target_version.to_s.inspect}"
         end

railties/lib/rails/generators/rails/app/templates/config/initializers/new_framework_defaults_7_2.rb.tt

@@ -66,11 +66,3 @@
 # on `Post`. With this option enabled, it will also look for a `:comments` association.
 #++
 # Rails.application.config.active_record.automatically_invert_plural_associations = true
-
-###
-# Controls whether Active Support should log tests without assertions.
-# This is helpful in detecting broken tests that do not perform intended assertions.
-# To disable this behavior, set the value to `:ignore` inside the `config/application.rb` (NOT this file).
-#
-#++
-# Rails.application.config.active_support.assertionless_tests_behavior = :log