Some notes: How we can test without formalized requirements

Understand the goal of the application: its purpose, its value to the customer
Learn the subject area and cultural characteristics
1. contact with testers/representatives of the country for which the app was developed
2. Google it!
  1. Find similar applications
3. Try to translate all that possible (menu, buttons, fields, comments...)
4. Find out: 1) main features 2) patterns 3) standards 4) prohibitions
Looking for requirements
1. Company
  1. Development team
  2. Product owner
    1. Information about risks
  3. Analysts
  4. Other testers
2. Other applications
  1. Similar in functionality
  2. Competitor Products
3. Experience
  1. Personal experience
  2. Common sense
  3. Use your experience! Remember about biases!
4. Google it!
  1. Checklists
  2. Typical requirements for similar applications
  3. Legislation or other regulations
Product customers
1. HelpDesk
2. Loyal customers
3. Focus groups
4. Feedback on the application
Documentation?
1. User Instructions
2. Wiki
3. Correspondence in messengers, social networks and etc.
4. Task Trackers (USs, bugs)
5. Code
  1. Structure
  2. Environment settings
  3. Functional
  4. Input/Output
  5. Unit tests
  6. Comments
6. Code storage
  1. Performers
  2. History
  3. Comments
Ad hoc testing
1. Check the known components
  1. Cheatlists
2. Typical checks
3. Find unhandled exceptions, errors
Exploratory Testing
1. Fix test sessions
  1. A bug?
  2. Feature?
  3. Any Doubts
2. Heuristics & Mnemonics
3. Test tours
4. Learn more about the application using DevTools (if possible)