📈 Generate parser benchmarks from test data

This was the primary reason for moving the response parser tests into
YAML: so I could easily create a benchmark suite based on them.

Author: nevans

benchmarks/generate_parser_benchmarks

@@ -0,0 +1,51 @@
+#!/usr/bin/env ruby
+
+require "yaml"
+require "pathname"
+require "net/imap"
+
+path = Pathname.new(__dir__) / "../test/net/imap/fixtures/response_parser"
+files = path.glob("*.yml")
+tests = files.flat_map {|file|
+  file.to_s
+    .then { YAML.unsafe_load_file _1 }
+    .fetch(:tests)
+    .select {|test_name, test|
+      :parser_assert_equal == test.fetch(:test_type) {
+        test.key?(:expected) ? :parser_assert_equal : :parser_pending
+      }
+    }
+    .map {|test_name, _|
+      [
+        file.relative_path_from(__dir__).to_s,
+        test_name.to_s,
+      ]
+    }
+}
+
+init = <<RUBY
+  require "yaml"
+  require "net/imap"
+
+  def load_response(file, name)
+    YAML.unsafe_load_file(file).dig(:tests, name, :response) \\
+      or abort "ERRORO: missing %p fixture data in %p" % [name, file]
+  end
+
+  parser   = Net::IMAP::ResponseParser.new
+RUBY
+
+prelude = <<RUBY
+  response = load_response(%p,
+                           %p)
+RUBY
+script = "parser.parse(response)"
+
+benchmarks = tests.map {|file, fixture_name|
+  name = fixture_name.delete_prefix("test_")
+  {name:, prelude: prelude % [file, fixture_name], script:}
+    .transform_keys(&:to_s)
+}
+  .sort_by { _1["name"] }
+
+puts YAML.dump({"prelude" => init, "benchmark" => benchmarks})