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Testing String Pattern Matching Utilities in Fluentd

This test suite validates the string utility functionality in Fluentd, focusing on pattern matching and null value handling. It ensures the StringUtil module correctly processes various string inputs and edge cases for the logging framework.

Test Coverage Overview

The test suite provides comprehensive coverage of string pattern matching functionality, particularly for null value detection.

Tests null string variations (-,null,NULL)
Validates normal string handling
Covers invalid string scenarios
Ensures proper regex pattern matching

Implementation Analysis

The testing approach utilizes Test::Unit’s sub_test_case structure to organize related test scenarios logically. The implementation leverages Ruby’s built-in regex capabilities and assertion methods to verify string matching behavior.

Uses setup method for pattern initialization
Implements discrete test cases for different string types
Employs assertion-based validation

Technical Details

Test Framework: Test::Unit
Primary Class: StringUtilTest
Key Dependencies: Fluent::StringUtil
Pattern Matching: Regular Expression
Test Organization: Hierarchical structure using sub_test_case

Best Practices Demonstrated

The test suite exemplifies strong testing practices through clear organization and thorough coverage.

Proper test isolation and setup
Logical grouping of related test cases
Clear test naming conventions
Coverage of both valid and invalid scenarios
Efficient use of setup method for shared resources

fluent/fluentd

test/plugin/test_string_util.rb

            
require_relative '../helper'
require 'fluent/plugin/string_util'

class StringUtilTest < Test::Unit::TestCase
  def setup
    @null_value_pattern = Regexp.new("^(-|null|NULL)$")
  end

  sub_test_case 'valid string' do
    test 'null string' do
      assert_equal Fluent::StringUtil.match_regexp(@null_value_pattern, "null").to_s, "null"
      assert_equal Fluent::StringUtil.match_regexp(@null_value_pattern, "NULL").to_s, "NULL"
      assert_equal Fluent::StringUtil.match_regexp(@null_value_pattern, "-").to_s, "-"
    end

    test 'normal string' do
      assert_equal Fluent::StringUtil.match_regexp(@null_value_pattern, "fluentd"), nil
    end
  end

  sub_test_case 'invalid string' do
    test 'normal string' do
      assert_equal Fluent::StringUtil.match_regexp(@null_value_pattern, "\xff"), nil
    end
  end
end