added rematch test to ease maintenance of tests

test/rematch.rb

@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require 'yaml/store'
+
+# Super simple and effective snapshot-like testing
+#
+# Instead of copying and pasting large helper outputs or big ruby
+# structures into the test files and updating them manually every time,
+# this class uses a YAML::Store file per each test file
+#
+# The first time a new `must_rematch` is run (i.e. it is not yet in the store file)
+# it records its returned value, so the next times the same test is run,
+# it will rematch its fresh returned value against the stored value.
+# Obviously, the test will fail if the values don't match.
+#
+# You can update the values (or purge the unused values) in a few ways:
+#  * delete the specific store file that you want to update
+#    (e.g. frontend_test.rb.yml) and rerun the test
+#  * set the env variable PAGY_REMATCH = 'true' and rerun all tests
+#  * manually edit the store file (useful only to try to fail a test)
+
+class Pagy
+  class Rematch
+    def initialize(path:, base:)
+      file = Pathname.new("#{path}.yml")
+      file.delete if !ENV['PAGY_REMATCH'].nil? && file.file?   # regenerate all the rematch files
+      @store = YAML::Store.new(file.to_s, true)
+      @base  = base
+      @count = 0
+    end
+
+    def rematch(value)
+      key = "#{@base} #{@count += 1}"
+      @store.transaction { |s| s.root?(key) ? s[key] : s[key] = value }
+    end
+
+    module Minitest
+      def before_setup
+        @rematch = Rematch.new(path: method(name).source_location.first, base: location)
+        super
+      end
+      def assert_rematch(_expected, actual)
+        assert_equal(@rematch.rematch(actual), actual)
+      end
+      infect_an_assertion :assert_rematch, :must_rematch if respond_to? :infect_an_assertion
+    end
+  end
+end

test/test_helper.rb

@@ -18,3 +18,5 @@
 require_relative 'mock_helpers/view'
 require_relative 'mock_helpers/controller'
 require 'minitest/autorun'
+require_relative 'rematch'
+Minitest::Spec.include Pagy::Rematch::Minitest