Describe the boundary value testing technique.

Defining input data: Identify all input fields and parameters in the system.
Identifying data types: Determine the data type for each input field (numeric, string, date, etc.).
Establishing boundaries: For each field with constraints (e.g., minimum/maximum value, length), define boundary values:
- Lower boundary
- Value just above the lower boundary
- Value just below the upper boundary
- Upper boundary
Selecting acceptable and unacceptable values:
- Acceptable: Any value within the established boundaries. Often, the middle value is chosen, but it is also useful to select values close to the middle of the interval.
- Unacceptable: Values outside the established boundaries. For example, values below the lower boundary and above the upper boundary.
Creating test cases: Develop test cases using combinations of acceptable and unacceptable boundary values for all input fields.
Executing tests: Run the developed test cases and verify that the actual results match the expected results.
Analyzing results: Analyze the testing results, identify defects, and document them.