Black Box Testing

Prime Numbers Testing Problem

📜 Story

BUGA is working on his stone computer.
His task? To test a function that checks if a number is prime!

But... there's a big problem – BUGA has no idea what a prime number is, let alone how to test one!
😱 Help him through this journey as he learns about equivalence partitioning, boundary value analysis, and unit testing.

Let’s guide BUGA step by step on how to properly test his function! 🔍🔥

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🛠 Step 1: Understanding the Problem

✅ BUGA's Dilemma:

"Me need to test… PRIME? But what PRIME? Me only know fire and rocks!" 🔥🪨

Before BUGA can test anything, he needs to understand:

• What is a prime number?
• What does the function take as input?
• What does it return as output?
• What are the pre and post conditions of the function?

📌 Task: Define the function specification

Help BUGA by filling in this table:

Aspect	Description
Function Name	isPrime
Input	?
Preconditions	?
Output	?
Postconditions	?

✍️ Fill in the missing parts to help BUGA understand the function!

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🛠 Step 2: Splitting Inputs into Equivalence Classes

✅ BUGA's Dilemma:

"Too many numbers!! Some prime, some no-prime. Me brain hurt! How split them?!" 🤯

Instead of testing infinite numbers, let’s group them into categories using Equivalence Partitioning.

📌 Task: Fill in the Equivalence Partitioning Table

Equivalence Class	Example Inputs	Expected Output	Notes
✅ E1: Valid Prime Numbers	2, 3, 5, 7, 11, ...	true
❌ E2: Non-Prime Natural Numbers	...	?
❌ ...	...	...

✍️ Complete the missing parts so BUGA can test smarter, not harder!

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🛠 Step 3: Finding the Tricky Edge Cases

✅ BUGA's Dilemma:

"Bugs… always hide in corners. Like saber-tooth cats in cave! Me must check dangerous edges." 🦷😨

BUGA needs to test Boundary Values—the critical numbers where bugs might appear.

📌 Task: Fill in the Boundary Value Analysis Table

Boundary Condition	Test Input	Expected Output	Reasoning
E1 Lower boundary - 1	1	false	the lower bound of E1 -1
E1 Lower boundary	2	true	the bound of E1
E1 Lower boundary + 1	3	true	the upper bound of E1
...	...	...	...

✍️ Help BUGA complete this table to catch tricky edge cases!

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🛠 Step 4: Writing Unit Tests in JUnit

✅ BUGA's Dilemma:

"Me must write tests in Java?!" 🪨💻

Now that BUGA understands what to test, he needs to write JUnit tests.

📌 Task: Write the JUnit test cases

import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;

@Tag("BBT")
class PrimeTest {
    @Test
    void testPrimeNumbersE1() {
        // TODO: Implement test for equivalence partition 1
        // given
        // when
        // then
    }

    @Test
    void testPrimeNumbersBvaE1() {
        // TODO: Implement test for boundary values of equivalence partition 1
        // given
        // when
        // then
    }
    ...
}

✍️ Help BUGA write the unit tests for all the identified EP and BVAs!

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Congratulations! You have successfully helped BUGA become a Black Box Testing Master! 🎉

🐒 Now go forth and test like a caveman… but smarter! 🦴💻🔥