Merge pull request rails#51176 from stevepolitodesign/assert-initializer

Introduce `Rails::Generators::Testing::Assertions#assert_initializer`

Author: rafaelfranca

railties/CHANGELOG.md

@@ -1,3 +1,13 @@
+*   Introduce `Rails::Generators::Testing::Assertions#assert_initializer`
+
+    Compliments the existing `initializer` generator action.
+
+    ```rb
+    assert_initializer "mail_interceptors.rb"
+    ```
+
+    *Steve Polito*
+
 *   Generate a .devcontainer folder and its contents when creating a new app.
 
     The .devcontainer folder includes everything needed to boot the app and do development in a remote container.

railties/lib/rails/generators/testing/assertions.rb

@@ -121,6 +121,26 @@ def assert_field_default_value(attribute_type, value)
             assert_equal(value, create_generated_attribute(attribute_type).default)
           end
         end
+
+        # Asserts a given initializer exists. You need to supply a path relative
+        # to the `config/initializers/` directory.
+        #
+        #   assert_initializer "mail_interceptors.rb"
+        #
+        # You can also give extra arguments. If the argument is a regexp, it will check if the
+        # regular expression matches the given file content. If it's a string, it compares the
+        # file with the given string:
+        #
+        #   assert_initializer "mail_interceptors.rb", /SandboxEmailInterceptor/
+        #
+        # Finally, when a block is given, it yields the file content:
+        #
+        #   assert_initializer "mail_interceptors.rb" do |initializer|
+        #     assert_match(/SandboxEmailInterceptor/, initializer)
+        #   end
+        def assert_initializer(name, *contents)
+          assert_file("config/initializers/#{name}", *contents)
+        end
       end
     end
   end

railties/test/generators/actions_test.rb

@@ -401,7 +401,7 @@ def test_rakefile_should_write_date_to_file_with_block_in_lib_tasks
 
   def test_initializer_should_write_date_to_file_in_config_initializers
     action :initializer, "constants.rb", "MY_CONSTANT = 42"
-    assert_file "config/initializers/constants.rb", "MY_CONSTANT = 42\n"
+    assert_initializer "constants.rb", "MY_CONSTANT = 42\n"
   end
 
   def test_initializer_should_write_date_to_file_with_block_in_config_initializers
@@ -411,7 +411,7 @@ def test_initializer_should_write_date_to_file_with_block_in_config_initializers
       end
     RUBY
     action(:initializer, "constants.rb") { code }
-    assert_file "config/initializers/constants.rb", code.strip_heredoc
+    assert_initializer "constants.rb", code.strip_heredoc
   end
 
   test "generate" do