Exam 1

• February 23th
• In-class Canvas exam
• May use a single-page, hand-written note sheet

How do we know if software works?

Software testing is the act of checking whether software satisfies expectations.

Testing

• Determines correctness in some scenarios
• Will not find all bugs

def square(n):
    return n*n

How do we know if this code works?

Test Cases

• We can confirm known outputs
• assert is a simple tool for this
• assert will raise an exception if its input expression if false

assert

assert(1==1) # Confirms that 1 is 1
assert(1==2) # Raises AssertionError

Square with Tests

def square(n):
    return n*n

assert(square(0) == 0)
assert(square(1) == 1)
assert(square(2) == 4)
assert(square(25) == 625)

Types of Tests

• Unit - Tests individual parts of the system
• Integration - Tests components integrated from smaller components
• End-to-end - Tests an entire system