Question

Expression unit test

Answer 1

[AI-generated answer — Bot GPT 3.5]

Unit test for an expression can be performed by creating test cases for various scenarios of input expressions and comparing the actual output of the expression with the expected output. Here is an example unit test for a simple arithmetic expression evaluator:

```python
import unittest

def evaluate_expression(expression):
return eval(expression)

class TestExpressionEvaluation(unittest.TestCase):

def test_simple_addition(self):
result = evaluate_expression("2+3")
self.assertEqual(result, 5)

def test_simple_subtraction(self):
result = evaluate_expression("5-2")
self.assertEqual(result, 3)

def test_complex_expression(self):
result = evaluate_expression("(3+2)*4")
self.assertEqual(result, 20)

def test_invalid_expression(self):
with self.assertRaises(Exception):
evaluate_expression("2+")

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

In this unit test, we have defined test cases for various scenarios such as simple addition and subtraction, a complex expression involving parentheses, and an invalid expression. We use the `unittest` module to define test cases and assertions to check the output of the expression evaluation function. The `unittest.main()` function runs all the test cases and reports any failures or errors.