Make expect_value actually check value

It is a matter of operator precedence. `do end` has lesser precedence
and thus the code

    expect(page).to have_selector("input") do
      ...
    end

is actually evaluated like

    expect(page).to(have_selector("input")) do
      ...
    end

Meaning the block is an argument to the `to` method. Looking into rspec
source code, the block is later discarded. So the value was never
actually checked.

The :css selector has been modified to allow usage of `value` in the
`have_selector` helper, which fixes the issue.

spec/support/capybara.rb

@@ -40,6 +40,16 @@ RSpec.configure do |config|
 
   # Set the default options
   config.include_context 'with default_url_options set', type: :feature
+
+  # Make it possible to match on value attribute.
+  #
+  # For instance:
+  #
+  #     expect(page).to have_selector(".date input", value: "2022-11-17")
+  #
+  Capybara.modify_selector(:css) do
+    filter(:value) { |node, v| node.value == v }
+  end
 end
 
 ##

spec/support/edit_fields/date_edit_field.rb

@@ -146,9 +146,7 @@ class DateEditField < EditField
   end
 
   def expect_value(value)
-    expect(page).to have_selector (".#{property_name} input") do |input|
-      input.value == value
-    end
+    expect(page).to have_selector(".#{property_name} input", value:)
   end
 
   def set_active_date(value)