Add jsonpath-compliance-test-suite tests

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "test/jsonpath-compliance-test-suite"]
+	path = test/jsonpath-compliance-test-suite
+	url = https://github.com/jsonpath-standard/jsonpath-compliance-test-suite.git

test/test_jsonpath_compliance.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'minitest/autorun'
+require 'jsonpath'
+require 'json'
+
+class TestJsonpathCompliance < MiniTest::Unit::TestCase
+  skipped = [
+    'whitespace, filter, space between parenthesized expression and bracket',
+    'whitespace, filter, return between parenthesized expression and bracket',
+    'filter, group terms, left',
+    'whitespace, filter, tab between parenthesized expression and bracket'
+  ]
+  JSON.parse(File.read('test/jsonpath-compliance-test-suite/cts.json')).fetch('tests').each_with_index do |test, index|
+    name = test['name']
+    method_name = name.gsub(/[^a-z0-9]+/, '_').sub(/_$/, '')
+    define_method("test_jsonpath_compliance_#{method_name}") do
+      skip "#{name} – skipping" if skipped.include?(name)
+      if test.key?('result')
+        result = Timeout.timeout(1) do
+          JsonPath.new(test.fetch('selector')).on(test['document'])
+        end
+        assert_equal(test['result'], result, "Test: #{name.inspect}")
+      elsif test['invalid_selector']
+        skip "skipping #{name} – invalid_selector #{test.fetch('selector').inspect}"
+      else
+        raise "don't know how to test #{name} – #{test.inspect}"
+      end
+    end
+  end
+end