How to make a test raise a 404 error instead of an ActiveRecord::RecordNotFound exception?

I'm trying to write a test to confirm that my application sends a 404 Not Found in response to a request for an invalid record (say a record with id=0).

My test code looks like this:

get '/pluralized_name_for_my_resource/0', as: :json
assert_response :not_found, "Doesn't return 404 Not Found for invalid id"

If I plug the corresponding URL into a browser, e.g. http://localhost:3000/pluralized_name_for_my_resource/0.json, the app raises the activerecord exception internally (and prints a message to the logs about it) but correctly responds with a 404 Not Found.

When I run the test, however, the exception isn't handled the same way. The test aborts and returns in the first get '/pluralized_... line and is reported as an error rather than a passing test.

How can I make my test environment handle the exception in the same way as my development environment, so that my test passes?

Solution

I did a bit of experimenting and given rails g scaffold foo and this test:

require "test_helper"

class FoosControllerTest < ActionDispatch::IntegrationTest
  setup do
    @foo = foos(:one)
  end

  test "should respond with not found" do
    get foo_url('xxxxxx'), as: :json
    assert_response :not_found
    assert_equal({ "status" => 404, "error"=>"Not Found"}, response.parsed_body)
  end
end

With the default settings the ActiveRecord::RecordNotFound exception is indeed not caught by the exception handler and bubbles up to the test.

Error:
FoosControllerTest#test_should_respond_with_not_found:
ActiveRecord::RecordNotFound: Couldn't find Foo with 'id'=xxxxxx
    app/controllers/foos_controller.rb:63:in `set_foo'
    test/controllers/foos_controller_test.rb:9:in `block in <class:FoosControllerTest>'

What seems to work is changing config.consider_all_requests_local and config.action_dispatch.show_exceptions in config/environments/test.rb:

# Show full error reports and disable caching.
config.consider_all_requests_local       = false # was true
config.action_controller.perform_caching = false
config.cache_store = :null_store

# Raise exceptions instead of rendering exception templates.
config.action_dispatch.show_exceptions = true # was false

With those two changes the test passes:

Running 1 tests in a single process (parallelization threshold is 50)
Run options: --seed 27622

# Running:

.

Finished in 0.270401s, 3.6982 runs/s, 7.3964 assertions/s.
1 runs, 2 assertions, 0 failures, 0 errors, 0 skips

However doing so might not be the best idea since its often useful that an exception in the application causes your tests to bail early. A hacky workaround is to use assert_raise to catch the exception when it bubbles up to the test:

require "test_helper"

class FoosControllerTest < ActionDispatch::IntegrationTest
  setup do
    @foo = foos(:one)
  end

  test "should respond with not found" do
    assert_raise(ActiveRecord::RecordNotFound) do
      get foo_url('xxxxxx'), as: :json
      assert_response :not_found
      assert_equal({ "status" => 404, "error"=>"Not Found"}, response.parsed_body)
    end
  end
end