Test input field with boundary values

Preconditions (3)

Step 1: Enter 0 in the input field and submit

Step 2: Verify the error message 'Input out of range' is displayed

Step 3: Enter 1 in the input field and submit

Step 4: Verify the success message 'Input accepted' is displayed

Step 5: Enter 100 in the input field and submit

Step 6: Verify the success message 'Input accepted' is displayed

Step 7: Enter 101 in the input field and submit

Step 8: Verify the error message 'Input out of range' is displayed

✅ Expected Result: The application correctly accepts inputs 1 and 100 and rejects inputs 0 and 101 with appropriate messages

Automation Requirements - Selenium with Python

Assertions Needed:

Verify error message 'Input out of range' appears for invalid inputs

Verify success message 'Input accepted' appears for valid inputs

Best Practices:

Use explicit waits to wait for messages to appear

Use clear and maintainable locators (e.g., By.ID or By.CSS_SELECTOR)

Separate test data from test logic

Use assertions that clearly check the message text

Automated Solution

Testing Fundamentals

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import unittest

class BoundaryValueTest(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()
        self.driver.get('http://example.com/input-form')  # Replace with actual URL
        self.wait = WebDriverWait(self.driver, 10)

    def enter_value_and_submit(self, value):
        input_field = self.wait.until(EC.presence_of_element_located((By.ID, 'number-input')))
        input_field.clear()
        input_field.send_keys(str(value))
        submit_button = self.driver.find_element(By.ID, 'submit-btn')
        submit_button.click()

    def get_message_text(self):
        message = self.wait.until(EC.visibility_of_element_located((By.ID, 'message')))
        return message.text

    def test_boundary_values(self):
        test_cases = [
            (0, 'Input out of range'),
            (1, 'Input accepted'),
            (100, 'Input accepted'),
            (101, 'Input out of range')
        ]
        for value, expected_message in test_cases:
            with self.subTest(value=value):
                self.enter_value_and_submit(value)
                actual_message = self.get_message_text()
                self.assertEqual(actual_message, expected_message, f'Failed for input {value}')

    def tearDown(self):
        self.driver.quit()

if __name__ == '__main__':
    unittest.main()

This test script uses Selenium with Python's unittest framework to automate boundary value analysis.

setUp: Opens the browser and navigates to the input form page.

enter_value_and_submit: Enters a value into the input field and clicks submit.

get_message_text: Waits for the message element to appear and returns its text.

test_boundary_values: Runs tests for four boundary values (0, 1, 100, 101) checking the displayed message matches expected.

tearDown: Closes the browser after tests.

Explicit waits ensure the test waits for elements and messages properly. Using subTest helps identify which input fails if any.

Common Mistakes - 4 Pitfalls

Using hardcoded sleep instead of explicit waits

Using brittle XPath locators that depend on full element paths

Not clearing the input field before entering new values

Not verifying the exact message text

Bonus Challenge

Now add data-driven testing with 3 different valid inputs and 3 invalid inputs using a test data structure

Show Hint