Boundary Value Analysis Tutorial

What is Boundary Value Analysis?

Boundary Value Analysis (BVA) is a software testing technique used to identify errors at the boundaries rather than within the ranges of input values. The premise of BVA is that the most errors occur at the edges of input ranges. It is particularly useful for testing conditions that involve numeric or ordinal values.

Why Use Boundary Value Analysis?

The rationale behind BVA is based on the observation that developers often make mistakes when dealing with boundary values. By focusing on these critical points, testers can enhance the likelihood of discovering defects. BVA complements Equivalence Partitioning, another testing technique, by identifying specific values that are at the edges of defined ranges.

How to Perform Boundary Value Analysis

To effectively implement BVA, follow these steps:

1. Identify the input variables and their valid ranges.
2. Determine the boundary values for each input variable.
3. Create test cases using these boundary values and their immediate neighbors.
4. Execute the test cases and evaluate the results.

Example of Boundary Value Analysis

Let's consider a simple example where a software application accepts an age input that must be between 18 and 65 years inclusive.

In this case, the test cases would be:

• Test case 1: Input = 17 (below lower boundary)
• Test case 2: Input = 18 (lower boundary)
• Test case 3: Input = 19 (just above lower boundary)
• Test case 4: Input = 64 (just below upper boundary)
• Test case 5: Input = 65 (upper boundary)
• Test case 6: Input = 66 (above upper boundary)

By testing these boundary values, we can ensure the application handles age inputs correctly at the edges of the defined range.

Testing Scenarios

For the age input example, the expected results for each input can be summarized as follows:

Conclusion

Boundary Value Analysis is a crucial technique in software testing that focuses on identifying potential defects at the edges of input ranges. By applying this method, testers can ensure that the software behaves as expected in critical scenarios, thus improving software quality and reliability.