How is internationalization testing conducted?

Internationalization (i18n) and localization (l10n) testing verify the correctness of the application's display and functionality across different languages, cultures, and regions.

Main stages:

1. Internationalization (i18n Testing): Focuses on the architecture and design of the application to ensure it can handle various languages and cultural formats without code changes.

   • Pseudo-localization testing: Replacing all text strings with special characters or elongated versions to check if the application correctly handles different string lengths and characters, and to identify hard-coded strings.
   • Culture-specific data handling testing: Ensures correct display and processing of:
     • Numeric formats and decimal separators.
     • Date and time formats.
     • Currency symbols and formats.
     • Units of measurement.
     • Sorting order.
   • Text scalability testing: Ensures the user interface displays correctly when text length increases significantly.
   • Encoding support testing: Checks proper handling of various character encodings (e.g., UTF-8).

2. Localization (l10n Testing): Focuses on verifying localized versions of the application for specific languages and regions.

   • Translated text testing: Checks the correctness and adequacy of translations, absence of grammatical errors and typos.
   • Localized content display testing: Ensures all UI elements (text, images, icons) are correctly displayed considering local features.
   • Functionality testing in localized environment: Verifies that all application functionalities work correctly with localized data.
   • Locale-specific formatting testing: Confirms correct display of date/time, numbers, currency, and other data formats according to local standards.
   • Cultural appropriateness testing: Assesses how well the content and UI match cultural norms and audience expectations.

Automation tools and methods can be used for:

• Checking the presence of all necessary localization keys.
• Detecting hard-coded strings.
• Verifying basic formatting of culture-bound data.
• Automating UI tests in localized environments using frameworks like Selenium or Appium.

# Example of checking localization keys in a file
import json

def check_localization_keys(default_lang_file, lang_file):
    with open(default_lang_file, 'r', encoding='utf-8') as f_default:
        default_keys = set(json.load(f_default).keys())

    with open(lang_file, 'r', encoding='utf-8') as f_lang:
        lang_keys = set(json.load(f_lang).keys())

    missing_keys = default_keys - lang_keys
    if missing_keys:
        print(f"Missing keys in {lang_file}: {missing_keys}")
    
    extra_keys = lang_keys - default_keys
    if extra_keys:
        print(f"Extra keys in {lang_file}: {extra_keys}")

# Call the function to compare keys of the default and another language
# check_localization_keys('en.json', 'ru.json')