Rule 1: Input Range or Interval (Numeric, Dates, Lengths)
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Understanding Input Ranges in Testing
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Today, we're going to dive into the first rule of Equivalence Class Testing, specifically focusing on input ranges or intervals. Can anyone tell me what an equivalence class is?
Is it a way to group inputs that can be expected to behave the same in our testing?
Exactly! Equivalence classes allow us to reduce the number of test cases we write by ensuring that if one input from a class works as expected, others will too. Now, what about identifying valid and invalid classes? Can anyone provide an example?
For instance, if we have a rule that says 'Age must be between 18 and 65', we could have a valid class for ages within that range, and invalid classes for anyone younger than 18 or older than 65.
Good job! This draws a important conclusion: classes help us focus on critical risks in the inputs. Let's remember the acronym 'VIV' β Valid and Invalid Classes β to keep these classifications in mind.
Creating Equivalence Classes for Different Input Types
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Now that we have a grasp on identifying equivalence classes, letβs talk about how to apply this to different inputs. Who can tell me how we might handle a set of discrete values?
If we had options like colorsβsay Red, Green, and Blueβwe'd identify one valid class for each color and an invalid class for any other color.
Exactly right! When it comes to discrete values, we treat each valid choice as its class. This is very different from handling ranges. Can someone tell me how to manage boolean values?
For boolean values, we'd typically just create two classes: one for True and one for False.
Spot on! And let's not forget that this approach helps in defining our tests earlier and more effectively. So, remember: when defining classes, VIV is key, but also think 'DB' for Discrete and Boolean!
Real-World Application of Equivalence Classes
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Letβs put this into a practical testing scenario. Suppose we are tasked with defining equivalence classes for a password policy. If passwords must be alphanumeric and at least 8 characters long, what could our classes look like?
We would have a valid class like 'Password123' comfortably over the length requirement, and then invalid classes for missing alphanumeric characters or being too short, like 'pass' or '12345678'.
Perfect! Those invalid classes are exactly what we want to target. Remember, specifying 'Must Be' characteristics is key in our tests. How about we quickly recap what we learned today about equivalence classes?
We learned to define valid and invalid classes based on input ranges or types, discrete values, and boolean states.
Excellent summary! Remember the rule of three: define at least one valid and two invalid classes every time!
Introduction & Overview
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Quick Overview
Standard
The section focuses on Rule 1 of Equivalence Class Testing (ECT), emphasizing the importance of accurately identifying valid and invalid equivalence classes for input ranges, numeric values, dates, and lengths. It outlines the process of defining these classes, setting the stage for structured test case generation.
Detailed
Rule 1: Input Range or Interval (Numeric, Dates, Lengths)
In software testing, particularly within the framework of Equivalence Class Testing (ECT), accurately identifying input ranges or intervals is crucial for generating effective test cases. Rule 1 focuses on specifying valid and invalid equivalence classes for numeric values, dates, and lengths. These ranges represent critical conditions that software must handle gracefully.
Key Points Covered:
- Defining Valid and Invalid Classes:
- For a given range, there will be at least one valid class containing values within the specified boundaries, alongside two invalid classes: one representing values lower than the desired range and another for values exceeding the upper limit.
- Example: For an input of 'Quantity must be between 1 and 100', valid equivalence class is [1, 100], invalids are [<1] (e.g., 0) and [>100] (e.g., 101).
- Specific Set of Values:
- When dealing with enumerated types or discrete values, each valid choice forms its own equivalence class, with invalid options categorized separately.
- Example: Payment methods (Valid: Credit Card, PayPal; Invalid: Cash).
- Boolean and Binary Conditions:
- Boolean inputs typically yield two equivalence classes corresponding to True and False.
- Example: For a condition 'Is User Active?' (True/False): valid ECs are both states.
- Presence of Must Be Characteristics:
- Inputs that are mandated to meet specific criteria (e.g., format, type) must be analyzed carefully to define what constitutes valid and invalid entries.
- Example: Passwords that must contain alphanumeric characters.
By implementing this rule of identifying equivalence classes when testing various input conditions, testers can ensure comprehensive coverage, enhance defect detection, and minimize redundancy in test cases.
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Identifying Equivalence Classes for Input Ranges
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Chapter Content
If an input condition specifies a valid range or interval of values (e.g., "Quantity must be between 1 and 100", "Age is 18-65 years", "File size 1KB to 10MB"), you should identify:
- At least one valid equivalence class: consisting of values within the specified valid range (e.g., any number between 1 and 100, such as 50).
- At least two invalid equivalence classes: one for values below the specified range (e.g., numbers less than 1, like 0 or -5) and one for values above the specified range (e.g., numbers greater than 100, like 101 or 200).
Detailed Explanation
When you're testing software that requires specific numeric inputs, it's important to understand the concept of equivalence classes. Equivalence classes help simplify test cases by categorizing inputs into valid and invalid ranges. For any given input condition that specifies a range, you can define at least one valid equivalence class that consists of values within that range and at least two invalid classes β one for values just below the minimum and one for values just above the maximum. This helps ensure comprehensive testing across the expected input spectrum.
Examples & Analogies
Imagine youβre a teacher responsible for grading tests, and you have a grading scale. If the acceptable score range is 1 to 100, you need to be clear that scores of 1 to 100 are valid (like an equivalence class), while scores of 0 or less are invalid, as are scores above 100. Identifying these clear classes helps you efficiently handle what you deem passing or failing grades.
Examples of Identifying Equivalence Classes
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Example: Integer Input for a Rating from 1 to 5.
- Valid EC: [1, 5] (e.g., 3)
- Invalid EC 1 (Below): [<1] (e.g., 0, -2)
- Invalid EC 2 (Above): [>5] (e.g., 6, 10)
Detailed Explanation
This example illustrates how to apply the rule of defining equivalence classes. For an input that allows ratings between 1 and 5, any rating that falls within this range (1, 2, 3, 4, or 5) is part of the valid equivalence class. However, if a user tries to input a score of 0 or -2, those inputs fall into an invalid class, representing values lower than the specified 1. Similarly, any number like 6 or 10 that exceeds the upper limit of 5 also forms another invalid equivalence class. By identifying these ranges, you can effectively prepare for testing and ensure your software behaves as expected regardless of the input.
Examples & Analogies
Think about when you go to a movie theater that only accepts ratings from 1 to 5 stars. If someone tries to give a rating of 0 or negative (like -1), or more than 5 stars, the system needs to reject those inputs. Your testing would ensure that the rating function behaves correctly regardless of whether someone inputs an acceptable number (like 4) or an unacceptable one (like 7).
Key Concepts
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Identification of Valid and Invalid Classes: Recognize the importance of defining both classes to enhance testing efficacy.
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Discrete Value Handling: Understand how to approach testing scenarios involving specific, distinct options.
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Boolean Values Simplification: Use binary classes to simplify the testing of boolean conditions.
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Must Be Characteristics: Identify critical attributes that input data must conform to.
Examples & Applications
An input field for age requiring values between 18 and 65 would have a valid equivalence class for any integer within that range and invalid classes for integers lower than 18 and greater than 65.
For a set of colors like Red, Green, and Blue, each color would form its own valid class, with an invalid class for any color outside of these choices.
Memory Aids
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Rhymes
When testing your inputs, do not fuss, Valid and invalid, it's a must!
Stories
Once upon a time in code-land, a brave tester had to categorize inputs. They knew to create groups: valid for acceptance, invalid for rejection. Thus they ventured forth, confident in their equivalence classes.
Memory Tools
VIV: Validate Input Values to remember Valid and Invalid classes.
Acronyms
DB
Discrete & Boolean - to remember handling rules for specific input types.
Flash Cards
Glossary
- Equivalence Class Testing (ECT)
A software testing approach that divides input data into equivalent groups for efficient test case generation.
- Valid Equivalence Class
A subset of input values that fall within the acceptable range or category for a specific test case.
- Invalid Equivalence Class
Input values that fall outside the acceptable range or category for a specific test case.
- Discrete Values
Specific, distinct values that a test case can take, such as options in a menu.
- Boolean Value
A binary condition representing true/false states.
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