Problem understanding some unit tests in Python distribution

[André]

Hi everyone,

In the hope of perhaps contributing some additional unit tests for
Python (thus contributing back to the community), I dove in the code
and found something that should be simple but that I can not wrap my
head around.

In list_tests.py, one finds
===
from test import test_support, seq_tests

class CommonTest(seq_tests.CommonTest):

def test_init(self):
# Iterable arg is optional
self.assertEqual(self.type2test([]), self.type2test())
# etc.
===

Wanting to figure out what the type2test() method does, I looked in
seq_tests.py and found the following:

===
class CommonTest(unittest.TestCase):
# The type to be tested
type2test = None

def test_constructors(self):
l0 = []
l1 = [0]
l2 = [0, 1]

u = self.type2test()
u0 = self.type2test(l0)
u1 = self.type2test(l1)
u2 = self.type2test(l2)

# etc.
===
No where do I find a definition for the type2test() method - other
than seeing it as a class variable defined to be None by default. I
looked in unittest.TestCase and did not see it anywhere.

Am I missing something obvious? I would appreciate if someone could
point me in the right direction.

Cheers,

André

 

[Peter Otten]

Hi everyone,

In the hope of perhaps contributing some additional unit tests for
Python (thus contributing back to the community), I dove in the code
and found something that should be simple but that I can not wrap my
head around.

In list_tests.py, one finds
===
from test import test_support, seq_tests

class CommonTest(seq_tests.CommonTest):

def test_init(self):
# Iterable arg is optional
self.assertEqual(self.type2test([]), self.type2test())
# etc.
===

Wanting to figure out what the type2test() method does, I looked in
seq_tests.py and found the following:

===
class CommonTest(unittest.TestCase):
# The type to be tested
type2test = None

def test_constructors(self):
l0 = []
l1 = [0]
l2 = [0, 1]

u = self.type2test()
u0 = self.type2test(l0)
u1 = self.type2test(l1)
u2 = self.type2test(l2)

# etc.
===
No where do I find a definition for the type2test() method - other
than seeing it as a class variable defined to be None by default. I
looked in unittest.TestCase and did not see it anywhere.

Am I missing something obvious? I would appreciate if someone could
point me in the right direction.

Use grep

CommonTest is not run standalone, it is used as a(n abstract) base class for
several other tests that override type2test.

E. g. in Lib/test/list_tests.py:

from test import test_support, seq_tests

class CommonTest(seq_tests.CommonTest):
....

And then in Lib/test/test_list.py:

from test import test_support, list_tests

class ListTest(list_tests.CommonTest):
type2test = list
....

Peter

 

[André]

Hi everyone,

In the hope of perhaps contributing some additional unit tests for
Python (thus contributing back to the community), I dove in the code
and found something that should be simple but that I can not wrap my
head around.

In list_tests.py, one finds
===
from test import test_support, seq_tests

class CommonTest(seq_tests.CommonTest):

    def test_init(self):
        # Iterable arg is optional
        self.assertEqual(self.type2test([]), self.type2test())
# etc.
===

Wanting to figure out what the type2test() method does, I looked in
seq_tests.py and found the following:

===
class CommonTest(unittest.TestCase):
    # The type to be tested
    type2test = None

    def test_constructors(self):
        l0 = []
        l1 = [0]
        l2 = [0, 1]

        u = self.type2test()
        u0 = self.type2test(l0)
        u1 = self.type2test(l1)
        u2 = self.type2test(l2)

# etc.
===
No where do I find a definition for the type2test() method - other
than seeing it as a class variable defined to be None by default.  I
looked in unittest.TestCase and did not see it anywhere.

Am I missing something obvious?  I would appreciate if someone could
point me in the right direction.

Use grep

I sort of did (use a "find all" from within my editor...)

CommonTest is not run standalone, it is used as a(n abstract) base class for
several other tests that override type2test.

E. g. in Lib/test/list_tests.py:

from test import test_support, seq_tests

class CommonTest(seq_tests.CommonTest):
...

And then in Lib/test/test_list.py:

from test import test_support, list_tests

class ListTest(list_tests.CommonTest):
    type2test = list

I can't believe I missed that one.

Thank you very much!

André