Expose `assert_queries` and `assert_no_queries` assertions

To assert the expected number of queries are made, Rails internally uses
`assert_queries` and `assert_no_queries`. These assertions can be
useful in applications as well.

By extracting these assertions to a module, the assertions can be
included where required.
These assertions are added to `ActiveSupport::TestCase` when
ActiveRecord is defined.

ActiveStorage, ActionView and ActionText are using this module now as
well, instead of duplicating the implementation.
The internal ActiveRecord::TestCase, used for testing ActiveRecord,
implements these assertions as well. However, these are slighlty more
advanced/complex and use the SQLCounter class. To keep things simple,
for now this implementation isn't used.

actiontext/test/test_helper.rb

@@ -6,6 +6,7 @@ require "active_support/testing/strict_warnings"
 ENV["RAILS_ENV"] = "test"
 
 require_relative "../test/dummy/config/environment"
+require "active_record/testing/query_assertions"
 ActiveRecord::Migrator.migrations_paths = [File.expand_path("../test/dummy/db/migrate", __dir__)]
 require "rails/test_help"
 
@@ -26,23 +27,7 @@ end
 class ActiveSupport::TestCase
   module QueryHelpers
     include ActiveJob::TestHelper
-
-    def assert_queries(expected_count, &block)
-      ActiveRecord::Base.connection.materialize_transactions
-
-      queries = []
-      ActiveSupport::Notifications.subscribe("sql.active_record") do |*, payload|
-        queries << payload[:sql] unless %w[ SCHEMA TRANSACTION ].include?(payload[:name])
-      end
-
-      result = _assert_nothing_raised_or_warn("assert_queries", &block)
-      assert_equal expected_count, queries.size, "#{queries.size} instead of #{expected_count} queries were executed. #{queries.inspect}"
-      result
-    end
-
-    def assert_no_queries(&block)
-      assert_queries(0, &block)
-    end
+    include ActiveRecord::Assertions::QueryAssertions
   end
 
   private

actionview/test/activerecord/relation_cache_test.rb

@@ -1,9 +1,11 @@
 # frozen_string_literal: true
 
 require "active_record_unit"
+require "active_record/testing/query_assertions"
 
 class RelationCacheTest < ActionView::TestCase
   tests ActionView::Helpers::CacheHelper
+  include ActiveRecord::Assertions::QueryAssertions
 
   def setup
     super
@@ -24,17 +26,4 @@ class RelationCacheTest < ActionView::TestCase
   end
 
   def view_cache_dependencies; []; end
-
-  def assert_queries(num, &block)
-    ActiveRecord::Base.connection.materialize_transactions
-    count = 0
-
-    ActiveSupport::Notifications.subscribe("sql.active_record") do |_name, _start, _finish, _id, payload|
-      count += 1 unless ["SCHEMA", "TRANSACTION"].include? payload[:name]
-    end
-
-    result = _assert_nothing_raised_or_warn("assert_queries", &block)
-    assert_equal num, count, "#{count} instead of #{num} queries were executed."
-    result
-  end
 end

activerecord/CHANGELOG.md

@@ -1,3 +1,19 @@
+*   Make `assert_queries` and `assert_no_queries` assertions public.
+
+    To assert the expected number of queries are made, Rails internally uses
+    `assert_queries` and `assert_no_queries`. These assertions can be now
+    be used in applications as well.
+
+    ```ruby
+    class ArticleTest < ActiveSupport::TestCase
+      test "queries are made" do
+         assert_queries(1) { Article.first }
+      end
+    end
+    ```
+
+    *Petrik de Heus*
+
 *   Fix `has_secure_token` calls the setter method on initialize.
 
     *Abeid Ahmed*

activerecord/lib/active_record/testing/query_assertions.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Assertions
+    module QueryAssertions
+      def assert_queries(expected_count, matcher: nil, &block)
+        ActiveRecord::Base.connection.materialize_transactions
+
+        queries = []
+        ActiveSupport::Notifications.subscribe("sql.active_record") do |*, payload|
+          queries << payload[:sql] if %w[ SCHEMA TRANSACTION ].exclude?(payload[:name]) && (matcher.nil? || payload[:sql].match(matcher))
+        end
+
+        result = _assert_nothing_raised_or_warn("assert_queries", &block)
+        assert_equal expected_count, queries.size, "#{queries.size} instead of #{expected_count} queries were executed. Queries: #{queries.join("\n\n")}"
+        result
+      end
+
+      def assert_no_queries(&block)
+        assert_queries(0, &block)
+      end
+    end
+  end
+end

activerecord/test/cases/assertions/query_assertions_test.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/post"
+require "active_record/testing/query_assertions"
+
+module ActiveRecord
+  module Assertions
+    class QueryAssertionsTest < ActiveSupport::TestCase
+      include QueryAssertions
+
+      def test_assert_queries
+        assert_queries(1) { Post.first }
+
+        error = assert_raises(Minitest::Assertion) {
+          assert_queries(2) { Post.first }
+        }
+        assert_match(/1 instead of 2 queries/, error.message)
+
+        error = assert_raises(Minitest::Assertion) {
+          assert_queries(0) { Post.first }
+        }
+        assert_match(/1 instead of 0 queries/, error.message)
+      end
+    end
+
+    def test_assert_no_queries
+      assert_no_queries { Post.none }
+
+      error = assert_raises(Minitest::Assertion) {
+        assert_no_queries { Post.first }
+      }
+      assert_match(/1 .* instead of 2/, error.message)
+    end
+  end
+end

activestorage/test/test_helper.rb

@@ -12,6 +12,8 @@ require "active_support/core_ext/object/try"
 require "active_support/testing/autorun"
 require "image_processing/mini_magick"
 
+require "active_record/testing/query_assertions"
+
 require "active_job"
 ActiveJob::Base.queue_adapter = :test
 ActiveJob::Base.logger = ActiveSupport::Logger.new(nil)
@@ -24,6 +26,7 @@ class ActiveSupport::TestCase
   self.file_fixture_path = ActiveStorage::FixtureSet.file_fixture_path
 
   include ActiveRecord::TestFixtures
+  include ActiveRecord::Assertions::QueryAssertions
 
   self.fixture_paths = [File.expand_path("fixtures", __dir__)]
 
@@ -35,23 +38,6 @@ class ActiveSupport::TestCase
     ActiveStorage::Current.reset
   end
 
-  def assert_queries(expected_count, matcher: nil, &block)
-    ActiveRecord::Base.connection.materialize_transactions
-
-    queries = []
-    ActiveSupport::Notifications.subscribe("sql.active_record") do |*, payload|
-      queries << payload[:sql] if %w[ SCHEMA TRANSACTION ].exclude?(payload[:name]) && (matcher.nil? || payload[:sql].match(matcher))
-    end
-
-    result = _assert_nothing_raised_or_warn("assert_queries", &block)
-    assert_equal expected_count, queries.size, "#{queries.size} instead of #{expected_count} queries were executed. Queries: #{queries.join("\n\n")}"
-    result
-  end
-
-  def assert_no_queries(&block)
-    assert_queries(0, &block)
-  end
-
   private
     def create_blob(key: nil, data: "Hello world!", filename: "hello.txt", content_type: "text/plain", identify: true, service_name: nil, record: nil)
       ActiveStorage::Blob.create_and_upload! key: key, io: StringIO.new(data), filename: filename, content_type: content_type, identify: identify, service_name: service_name, record: record

railties/lib/rails/test_help.rb

@@ -11,15 +11,16 @@ require "action_controller"
 require "action_controller/test_case"
 require "action_dispatch/testing/integration"
 require "rails/generators/test_case"
-
 require "active_support/testing/autorun"
 
 require "rails/testing/maintain_test_schema"
 
 if defined?(ActiveRecord::Base)
+  require "active_record/testing/query_assertions"
   ActiveSupport.on_load(:active_support_test_case) do
     include ActiveRecord::TestDatabases
     include ActiveRecord::TestFixtures
+    include ActiveRecord::Assertions::QueryAssertions
 
     self.fixture_paths << "#{Rails.root}/test/fixtures/"
     self.file_fixture_path = "#{Rails.root}/test/fixtures/files"