assert has strange behavior with numpy arrays

[pytestbot]

Originally reported by: Anonymous

---

import numpy as np

def test_array():
assert not(any(np.array([0, -1]) < 0))

I have this file as test3.py
If I run this with
py.test test3.py

I get the following output
$ py.test test3.py
============================= test session starts ==============================
platform linux2 -- Python 2.6.6 -- pytest-2.0.0
collected 1 items

test3.py F

=================================== FAILURES ===================================
__________________________________ test_array __________________________________

self = AssertionError()

def __init__(self, *args):
    BuiltinAssertionError.__init__(self, *args)
    if args:
        try:
            self.msg = str(args[0])
        except py.builtin._sysex:
            raise
        except:
            self.msg = "<[broken __repr__] %s at %0xd>" %(
                args[0].__class__, id(args[0]))
    else:
        f = py.code.Frame(sys._getframe(1))
        try:
            source = f.code.fullsource
            if source is not None:
                try:
                    source = source.getstatement(f.lineno, assertion=True)
                except IndexError:
                    source = None
                else:
                    source = str(source.deindent()).strip()
        except py.error.ENOENT:
            source = None
            # this can also occur during reinterpretation, when the
            # co_filename is set to "<run>".
        if source:

          self.msg = reinterpret(source, f, should_fail=True)

/usr/local/lib/python2.6/dist-packages/py/_code/assertion.py:79:

---

source = 'assert not(any(np.array([0, -1]) < 0))'
frame = <py._code.code.Frame object at 0x96208cc>, should_fail = True

def interpret(source, frame, should_fail=False):
    mod = ast.parse(source)
    visitor = DebugInterpreter(frame)
    try:

      visitor.visit(mod)

/usr/local/lib/python2.6/dist-packages/py/_code/_assertionnew.py:48:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
node = <_ast.Module object at 0x96788ac>

def visit(self, node):
    """Visit a node."""
    method = 'visit_' + node.__class__.__name__
    visitor = getattr(self, method, self.generic_visit)

  return visitor(node)

/usr/lib/python2.6/ast.py:231:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
mod = <_ast.Module object at 0x96788ac>

def visit_Module(self, mod):
    for stmt in mod.body:

      self.visit(stmt)

/usr/local/lib/python2.6/dist-packages/py/_code/_assertionnew.py:146:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
node = <_ast.Assert object at 0x967872c>

def visit(self, node):
    """Visit a node."""
    method = 'visit_' + node.__class__.__name__
    visitor = getattr(self, method, self.generic_visit)

  return visitor(node)

/usr/lib/python2.6/ast.py:231:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
assrt = <_ast.Assert object at 0x967872c>

def visit_Assert(self, assrt):

  test_explanation, test_result = self.visit(assrt.test)

/usr/local/lib/python2.6/dist-packages/py/_code/_assertionnew.py:319:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
node = <_ast.UnaryOp object at 0x96785ac>

def visit(self, node):
    """Visit a node."""
    method = 'visit_' + node.__class__.__name__
    visitor = getattr(self, method, self.generic_visit)

  return visitor(node)

/usr/lib/python2.6/ast.py:231:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
unary = <_ast.UnaryOp object at 0x96785ac>

def visit_UnaryOp(self, unary):
    pattern = unary_map[unary.op.__class__]

  operand_explanation, operand_result = self.visit(unary.operand)

/usr/local/lib/python2.6/dist-packages/py/_code/_assertionnew.py:202:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
node = <_ast.Call object at 0x96789cc>

def visit(self, node):
    """Visit a node."""
    method = 'visit_' + node.__class__.__name__
    visitor = getattr(self, method, self.generic_visit)

  return visitor(node)

/usr/lib/python2.6/ast.py:231:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
call = <_ast.Call object at 0x96789cc>

def visit_Call(self, call):
    func_explanation, func = self.visit(call.func)
    arg_explanations = []
    ns = {"__exprinfo_func" : func}
    arguments = []
    for arg in call.args:

      arg_explanation, arg_result = self.visit(arg)

/usr/local/lib/python2.6/dist-packages/py/_code/_assertionnew.py:232:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
node = <_ast.Compare object at 0x9678a0c>

def visit(self, node):
    """Visit a node."""
    method = 'visit_' + node.__class__.__name__
    visitor = getattr(self, method, self.generic_visit)

  return visitor(node)

/usr/lib/python2.6/ast.py:231:

---

self = <py._code._assertionnew.DebugInterpreter object at 0x9678a4c>
comp = <_ast.Compare object at 0x9678a0c>

def visit_Compare(self, comp):
    left = comp.left
    left_explanation, left_result = self.visit(left)
    for op, next_op in zip(comp.ops, comp.comparators):
        next_explanation, next_result = self.visit(next_op)
        op_symbol = operator_map[op.__class__]
        explanation = "%s %s %s" % (left_explanation, op_symbol,
                                    next_explanation)
        source = "__exprinfo_left %s __exprinfo_right" % (op_symbol,)
        co = self._compile(source)
        try:
            result = self.frame.eval(co, __exprinfo_left=left_result,
                                     __exprinfo_right=next_result)
        except Exception:
            raise Failure(explanation)

      if not result:

E ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

/usr/local/lib/python2.6/dist-packages/py/_code/_assertionnew.py:177: ValueError
=========================== 1 failed in 0.23 seconds ===========================
$

---

• Bitbucket: https://bitbucket.org/pytest-dev/pytest/issue/10

[pytestbot]

Original comment by holger krekel (BitBucket: hpk42, GitHub: hpk42):

---

fix issue10 - numpy arrays should now work better in assertion expressions
(or any other objects which have an exception-raising nonzero method ...)