Prop Testing
What is a function? Are they easy to test?
| x | f(x) |
|---|---|
| - | + |
| 0 | 0 |
| + | + |
Simple Tests
Square of a Number
Gradient of a function
- Positive slope (multiple tests)
- Negative slope
- Zero slope:
- Undefined slope (vertical line):
- Large coordinate values:
- Identical points:
Simple Tests
Tax Calculator
Hash Function
Random Numbers
Best Effort: Without getting all equivalent classes
Has to be a better way
Properties for Integers
from hypothesis import given, strategies as st
@given(st.integers(), st.integers())
def test_ints_are_commutative(x, y):
assert x + y == y + x
@given(x=st.integers(), y=st.integers())
def test_ints_cancel(x, y):
assert (x + y) - y == x
@given(st.lists(st.integers()))
def test_reversing_twice_gives_same_list(xs):
# This will generate lists of arbitrary length (usually between 0 and
# 100 elements) whose elements are integers.
ys = list(xs)
ys.reverse()
ys.reverse()
assert xs == ys
@given(st.tuples(st.booleans(), st.text()))
def test_look_tuples_work_too(t):
# A tuple is generated as the one you provided, with the corresponding
# types in those positions.
assert len(t) == 2
assert isinstance(t[0], bool)
assert isinstance(t[1], str)
Properties for Random Numbers?
RANDOM Numbers
74 8 38 100 75 63 37 53 95 51 56 62 31 54 28 96 72 31 23 17 58 100 15 7 48 9 20 26 62 69 31 31 81 88 77 78 80 9 91 98 93 93 90 33 40 60 80 66 26 97 69 90 24 3 85 100 4 72 8 24 28 16 40 80 56 7 94 20 42 42 13 44 73 24 29 69 78 83 17 24
random data from weather noise
rand() on windows
Demo Time
Counter + Floor Random
https://chatgpt.com/c/67ad6a59-22f0-800c-a5af-db768fb299b2
RANDU
PRNG
MERSANNE TWISTER
Stateful Stateless / Hypothesis Demo
SchemaThesis
Prop Testing
By Iqbal Talaat Bhatti
