Software Testing Tutorial #35 - Boundary Value Analysis in Testing

Summary

This tutorial delves into Boundary Value Analysis (BVA), a critical software testing technique that complements Equivalence Partitioning (EP). The instructor uses a relatable house-building analogy to explain BVA, emphasizing the importance of testing at boundary values where software often fails. The tutorial demonstrates how to apply both techniques together to create effective test cases for maximum component coverage, highlighting their necessity for manual testers and those aspiring to excel in software testing.

Takeaways

• 😀 Boundary Value Analysis (BVA) is a software testing technique that focuses on the boundaries of input ranges and values.
• 🔍 BVA is often used in conjunction with Equivalence Partitioning (EP) to create comprehensive test cases.
• 🏠 The script uses the analogy of building a house to explain BVA, emphasizing the importance of defining boundaries before constructing the 'house' or test cases.
• 📊 Equivalence Partitioning divides the input range into valid and invalid partitions to simplify testing by reducing the number of test cases needed.
• 📈 The tutorial provides a discount example to illustrate how to apply both EP and BVA to identify test cases with maximum coverage.
• 🛑 BVA is crucial for identifying potential failures at the boundaries of input ranges, where software components are more likely to fail due to calculation and logic errors.
• 📝 The script explains how to determine the lower and upper boundary values for each partition and the importance of testing these values.
• 📉 Invalid partitions, such as purchases below $1 or above $5001, are also considered in BVA to ensure the software handles these cases correctly.
• 🔑 The tutorial emphasizes the importance of testing both within and at the boundaries of valid partitions to achieve full test coverage.
• 📚 Understanding BVA and EP is essential for manual testers and those looking to enter the field of software testing.
• 💼 The concepts of BVA and EP are valuable for explaining test design techniques during interviews for software testing roles.

Q & A

What is Boundary Value Analysis (BVA)?

Boundary Value Analysis is a black box software testing technique that focuses on testing inputs at the boundaries of an input domain. It is often used in conjunction with Equivalence Partitioning (EP) to ensure maximum test coverage.

How does Boundary Value Analysis complement Equivalence Partitioning?

Equivalence Partitioning divides the input data into groups that are expected to behave similarly, while Boundary Value Analysis focuses on the edge values of these partitions. By combining both techniques, testers can ensure that both the normal and edge cases are thoroughly tested.

Can you provide an example of how to apply Boundary Value Analysis in a real-world scenario?

The script uses the example of building a house on a plot of land. Just as you define the boundaries of your land before construction, in BVA, you define the boundaries of input values and then test within those boundaries to ensure the software behaves as expected.

What is the significance of testing at boundary values in software testing?

Software components often fail at boundary values due to calculation and logic errors. Testing at these points helps identify potential issues that might not be caught with random testing within the range of valid inputs.

How does the script illustrate the concept of valid and invalid partitions in the context of a discount example?

The script uses a discount example where different discount rates apply based on the amount spent. Valid partitions are the ranges of spending that qualify for specific discounts, while invalid partitions are values outside these ranges, such as amounts less than $1 or more than $5001, which are not allowed to purchase.

What are the boundary values for the 5% discount partition in the given example?

For the 5% discount partition, the lower boundary value is $1.00, and the upper boundary value is $100.99, assuming the software does not round up to the next dollar.

How many boundary values are identified in the script for the discount example?

The script identifies 10 boundary values across different discount partitions, including both valid and invalid boundaries.

Why is it important to test values between the boundary values in addition to the boundaries themselves?

Testing values between boundary values ensures that the software behaves correctly within the entire range of valid inputs, not just at the edges. This helps achieve comprehensive test coverage and identify any potential issues that could arise within the input range.

What is the purpose of combining Equivalence Partitioning and Boundary Value Analysis in software testing?

Combining these two techniques helps create a structured approach to testing that covers both typical and edge case scenarios. This method reduces the chance of missing critical test cases and provides clarity in test case design.

How does understanding BVA and EP help someone get into a software testing job?

Understanding BVA and EP demonstrates knowledge of fundamental black box testing techniques, which are essential for manual testers and those looking to enter the field of software testing. Being able to explain and apply these concepts can make a candidate more attractive to potential employers.