Software Testing Tutorial #34 - Equivalence Partitioning in Testing

Summary

This software testing tutorial introduces equivalence partitioning, a crucial black box test design technique widely used in the industry. The instructor explains the concept with a simple e-commerce discount module example, demonstrating how to divide test cases into valid and invalid partitions to ensure broad coverage with minimal tests. The tutorial also highlights the importance of understanding equivalence partitioning for software testing interviews and hints at the next topic: boundary value analysis, which complements equivalence partitioning for robust test design.

Takeaways

• 😀 Equivalence Partitioning is an important black box test design technique widely used in software testing.
• 📘 It is a common interview question for software testing roles, and understanding it with examples can help during interviews.
• 🔍 The concept involves dividing input data into partitions that are considered equivalent in terms of expected software behavior.
• 🛍️ An example given is testing a discount module on an e-commerce website, where different discount rates apply based on purchase amounts.
• 💰 The discounts are divided into partitions: 5% for $1-$100, 10% for $101-$200, 20% for $201-$500, and 25% for amounts over $500 up to a maximum allowed purchase.
• ❌ Invalid partitions are also considered, such as purchases under $1 or over the maximum allowed amount, which should not be accepted by the application.
• 📝 Equivalence Partitioning helps in creating a minimal number of test cases that provide broad coverage, avoiding the need for exhaustive testing.
• 🔑 It is crucial for understanding when to apply certain values to test and what outcomes to expect, thus streamlining the testing process.
• 🔄 Equivalence Partitioning is often used in conjunction with Boundary Value Analysis (BVA) for stronger test case documentation and better coverage.
• 📚 The tutorial promises to cover BVA in a subsequent session, explaining how it complements Equivalence Partitioning.
• 🤔 The script encourages viewers to think of other examples and to ask questions or request further tutorials on Equivalence Partitioning for deeper understanding.

Q & A

What is equivalence partitioning in the context of software testing?

Equivalence partitioning is a black box test design technique used in software testing to divide the input of a software module into groups of similar data from which test cases can be derived. It helps in minimizing the number of test cases while ensuring broad coverage of the software's functionality.

Why is equivalence partitioning important for software testers?

Equivalence partitioning is important for software testers because it allows them to create a minimal number of test cases that still provide comprehensive test coverage, which is crucial for efficient and effective software testing.

What is the significance of equivalence partitioning in software testing interviews?

Equivalence partitioning is a widely asked question in software testing interviews as it demonstrates a candidate's understanding of fundamental test design techniques, and the ability to apply them with practical examples.

Can you provide an example of how equivalence partitioning is applied in an e-commerce website discount module?

In the script, an e-commerce website discount module is used as an example where purchases are categorized into different discount tiers based on the amount spent. Equivalence partitioning helps in dividing these categories into valid partitions (e.g., 1-100 for a 5% discount, 101-200 for a 10% discount) and invalid partitions (e.g., amounts less than 1 or more than 5000).

What are the different types of partitions mentioned in the script for the e-commerce discount module?

The script mentions valid partitions for different discount rates such as 5% for purchases between $1 and $100, 10% for $101 to $200, 20% for $201 to $500, and 25% for amounts above $500 up to the maximum allowed purchase value. Invalid partitions include purchases less than $1 and amounts exceeding the maximum allowed purchase value.

How does equivalence partitioning help in reducing the number of test cases needed?

Equivalence partitioning helps in reducing the number of test cases by identifying that within each valid partition, any value will produce the same outcome, thus only requiring a few representative test cases from each partition to ensure coverage.

What is the relationship between equivalence partitioning and boundary value analysis?

Equivalence partitioning and boundary value analysis are complementary techniques. While equivalence partitioning divides the input space into logical partitions, boundary value analysis focuses on the edges of these partitions to ensure that boundary conditions are tested.

How does the script suggest selecting test cases from equivalence partitions?

The script suggests selecting a few representative values from each valid partition (e.g., $50, $100 for the 5% discount partition) and testing edge cases in the invalid partitions (e.g., $0.99, $100.01) to ensure comprehensive coverage.

What is the purpose of invalid partitions in equivalence partitioning?

Invalid partitions in equivalence partitioning are used to test the software's behavior with out-of-bound or unexpected inputs, ensuring that the software can handle errors or invalid data gracefully.

Can you explain the example of a web page text box given in the script using equivalence partitioning?

In the script, a web page text box that accepts whole numbers between 1 and 200 is used as an example. Equivalence partitioning would consider the range of 1 to 200 as a valid partition, while values less than 1 or greater than 200 would be considered invalid partitions.

How does the script suggest combining equivalence partitioning with other testing techniques?

The script suggests that equivalence partitioning, when used in conjunction with boundary value analysis, provides a robust approach to test case design, ensuring comprehensive test coverage with a minimal number of test cases.