# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
"""Oddball cases for testing coverage.py"""
import sys
from flaky import flaky
import pytest
import coverage
from coverage import env
from coverage.backward import import_local_file
from coverage.files import abs_file
from tests.coveragetest import CoverageTest
from tests import osinfo
class ThreadingTest(CoverageTest):
"""Tests of the threading support."""
def test_threading(self):
self.check_coverage("""\
import threading
def fromMainThread():
return "called from main thread"
def fromOtherThread():
return "called from other thread"
def neverCalled():
return "no one calls me"
other = threading.Thread(target=fromOtherThread)
other.start()
fromMainThread()
other.join()
""",
[1, 3, 4, 6, 7, 9, 10, 12, 13, 14, 15], "10")
def test_thread_run(self):
self.check_coverage("""\
import threading
class TestThread(threading.Thread):
def run(self):
self.a = 5
self.do_work()
self.a = 7
def do_work(self):
self.a = 10
thd = TestThread()
thd.start()
thd.join()
""",
[1, 3, 4, 5, 6, 7, 9, 10, 12, 13, 14], "")
class RecursionTest(CoverageTest):
"""Check what happens when recursive code gets near limits."""
def test_short_recursion(self):
# We can definitely get close to 500 stack frames.
self.check_coverage("""\
def recur(n):
if n == 0:
return 0
else:
return recur(n-1)+1
recur(495) # We can get at least this many stack frames.
i = 8 # and this line will be traced
""",
[1, 2, 3, 5, 7, 8], "")
def test_long_recursion(self):
# We can't finish a very deep recursion, but we don't crash.
with self.assertRaises(RuntimeError):
self.check_coverage("""\
def recur(n):
if n == 0:
return 0
else:
return recur(n-1)+1
recur(100000) # This is definitely too many frames.
""",
[1, 2, 3, 5, 7], ""
)
def test_long_recursion_recovery(self):
# Test the core of bug 93: https://bitbucket.org/ned/coveragepy/issue/93
# When recovering from a stack overflow, the Python trace function is
# disabled, but the C trace function is not. So if we're using a
# Python trace function, we won't trace anything after the stack
# overflow, and there should be a warning about it. If we're using
# the C trace function, only line 3 will be missing, and all else
# will be traced.
self.make_file("recur.py", """\
def recur(n):
if n == 0:
return 0 # never hit
else:
return recur(n-1)+1
try:
recur(100000) # This is definitely too many frames.
except RuntimeError:
i = 10
i = 11
""")
cov = coverage.Coverage()
self.start_import_stop(cov, "recur")
pytrace = (cov._collector.tracer_name() == "PyTracer")
expected_missing = [3]
if pytrace: # pragma: no metacov
expected_missing += [9, 10, 11]
_, statements, missing, _ = cov.analysis("recur.py")
self.assertEqual(statements, [1, 2, 3, 5, 7, 8, 9, 10, 11])
self.assertEqual(missing, expected_missing)
# Get a warning about the stackoverflow effect on the tracing function.
if pytrace: # pragma: no metacov
self.assertEqual(cov._warnings,
["Trace function changed, measurement is likely wrong: None"]
)
else:
self.assertEqual(cov._warnings, [])
class MemoryLeakTest(CoverageTest):
"""Attempt the impossible: test that memory doesn't leak.
Note: this test is truly unusual, and has had a colorful history. See
for example: https://bitbucket.org/ned/coveragepy/issue/186
It may still fail occasionally, especially on PyPy.
"""
@flaky
def test_for_leaks(self):
if env.JYTHON:
self.skipTest("Don't bother on Jython")
# Our original bad memory leak only happened on line numbers > 255, so
# make a code object with more lines than that. Ugly string mumbo
# jumbo to get 300 blank lines at the beginning..
code = """\
# blank line\n""" * 300 + """\
def once(x): # line 301
if x % 100 == 0:
raise Exception("100!")
elif x % 2:
return 10
else: # line 306
return 11
i = 0 # Portable loop without alloc'ing memory.
while i < ITERS:
try:
once(i)
except:
pass
i += 1 # line 315
"""
lines = list(range(301, 315))
lines.remove(306) # Line 306 is the "else".
# This is a non-deterministic test, so try it a few times, and fail it
# only if it predominantly fails.
fails = 0
for _ in range(10):
ram_0 = osinfo.process_ram()
self.check_coverage(code.replace("ITERS", "10"), lines, "")
ram_10 = osinfo.process_ram()
self.check_coverage(code.replace("ITERS", "10000"), lines, "")
ram_10k = osinfo.process_ram()
# Running the code 10k times shouldn't grow the ram much more than
# running it 10 times.
ram_growth = (ram_10k - ram_10) - (ram_10 - ram_0)
if ram_growth > 100000:
fails += 1 # pragma: only failure
if fails > 8:
self.fail("RAM grew by %d" % (ram_growth)) # pragma: only failure
class MemoryFumblingTest(CoverageTest):
"""Test that we properly manage the None refcount."""
def test_dropping_none(self): # pragma: not covered
if not env.C_TRACER:
self.skipTest("Only the C tracer has refcounting issues")
# TODO: Mark this so it will only be run sometimes.
self.skipTest("This is too expensive for now (30s)")
# Start and stop coverage thousands of times to flush out bad
# reference counting, maybe.
self.make_file("the_code.py", """\
import random
def f():
if random.random() > .5:
x = 1
else:
x = 2
""")
self.make_file("main.py", """\
import coverage
import sys
from the_code import f
for i in range(10000):
cov = coverage.Coverage(branch=True)
cov.start()
f()
cov.stop()
cov.erase()
print("Final None refcount: %d" % (sys.getrefcount(None)))
""")
status, out = self.run_command_status("python main.py")
self.assertEqual(status, 0)
self.assertIn("Final None refcount", out)
self.assertNotIn("Fatal", out)
class PyexpatTest(CoverageTest):
"""Pyexpat screws up tracing. Make sure we've counter-defended properly."""
def test_pyexpat(self):
if env.JYTHON:
self.skipTest("Pyexpat isn't a problem on Jython")
# pyexpat calls the trace function explicitly (inexplicably), and does
# it wrong for exceptions. Parsing a DOCTYPE for some reason throws
# an exception internally, and triggers its wrong behavior. This test
# checks that our fake PyTrace_RETURN hack in tracer.c works. It will
# also detect if the pyexpat bug is fixed unbeknownst to us, meaning
# we'd see two RETURNs where there should only be one.
self.make_file("trydom.py", """\
import xml.dom.minidom
XML = '''\\
'''
def foo():
dom = xml.dom.minidom.parseString(XML)
assert len(dom.getElementsByTagName('child')) == 2
a = 11
foo()
""")
self.make_file("outer.py", "\n"*100 + "import trydom\na = 102\n")
cov = coverage.Coverage()
cov.erase()
# Import the Python file, executing it.
self.start_import_stop(cov, "outer")
_, statements, missing, _ = cov.analysis("trydom.py")
self.assertEqual(statements, [1, 3, 8, 9, 10, 11, 13])
self.assertEqual(missing, [])
_, statements, missing, _ = cov.analysis("outer.py")
self.assertEqual(statements, [101, 102])
self.assertEqual(missing, [])
# Make sure pyexpat isn't recorded as a source file.
# https://bitbucket.org/ned/coveragepy/issues/419/nosource-no-source-for-code-path-to-c
files = cov.get_data().measured_files()
self.assertFalse(
any(f.endswith("pyexpat.c") for f in files),
"Pyexpat.c is in the measured files!: %r:" % (files,)
)
class ExceptionTest(CoverageTest):
"""I suspect different versions of Python deal with exceptions differently
in the trace function.
"""
def test_exception(self):
# Python 2.3's trace function doesn't get called with "return" if the
# scope is exiting due to an exception. This confounds our trace
# function which relies on scope announcements to track which files to
# trace.
#
# This test is designed to sniff this out. Each function in the call
# stack is in a different file, to try to trip up the tracer. Each
# file has active lines in a different range so we'll see if the lines
# get attributed to the wrong file.
self.make_file("oops.py", """\
def oops(args):
a = 2
raise Exception("oops")
a = 4
""")
self.make_file("fly.py", "\n"*100 + """\
def fly(calls):
a = 2
calls[0](calls[1:])
a = 4
""")
self.make_file("catch.py", "\n"*200 + """\
def catch(calls):
try:
a = 3
calls[0](calls[1:])
a = 5
except:
a = 7
""")
self.make_file("doit.py", "\n"*300 + """\
def doit(calls):
try:
calls[0](calls[1:])
except:
a = 5
""")
# Import all the modules before starting coverage, so the def lines
# won't be in all the results.
for mod in "oops fly catch doit".split():
import_local_file(mod)
# Each run nests the functions differently to get different
# combinations of catching exceptions and letting them fly.
runs = [
("doit fly oops", {
'doit.py': [302, 303, 304, 305],
'fly.py': [102, 103],
'oops.py': [2, 3],
}),
("doit catch oops", {
'doit.py': [302, 303],
'catch.py': [202, 203, 204, 206, 207],
'oops.py': [2, 3],
}),
("doit fly catch oops", {
'doit.py': [302, 303],
'fly.py': [102, 103, 104],
'catch.py': [202, 203, 204, 206, 207],
'oops.py': [2, 3],
}),
("doit catch fly oops", {
'doit.py': [302, 303],
'catch.py': [202, 203, 204, 206, 207],
'fly.py': [102, 103],
'oops.py': [2, 3],
}),
]
for callnames, lines_expected in runs:
# Make the list of functions we'll call for this test.
callnames = callnames.split()
calls = [getattr(sys.modules[cn], cn) for cn in callnames]
cov = coverage.Coverage()
cov.start()
# Call our list of functions: invoke the first, with the rest as
# an argument.
calls[0](calls[1:]) # pragma: nested
cov.stop() # pragma: nested
# Clean the line data and compare to expected results.
# The file names are absolute, so keep just the base.
clean_lines = {}
data = cov.get_data()
for callname in callnames:
filename = callname + ".py"
lines = data.lines(abs_file(filename))
clean_lines[filename] = sorted(lines)
if env.JYTHON: # pragma: only jython
# Jython doesn't report on try or except lines, so take those
# out of the expected lines.
invisible = [202, 206, 302, 304]
for lines in lines_expected.values():
lines[:] = [l for l in lines if l not in invisible]
self.assertEqual(clean_lines, lines_expected)
class DoctestTest(CoverageTest):
"""Tests invoked with doctest should measure properly."""
def test_doctest(self):
self.check_coverage('''\
def return_arg_or_void(arg):
"""If is None, return "Void"; otherwise return
>>> return_arg_or_void(None)
'Void'
>>> return_arg_or_void("arg")
'arg'
>>> return_arg_or_void("None")
'None'
"""
if arg is None:
return "Void"
else:
return arg
import doctest, sys
doctest.testmod(sys.modules[__name__]) # we're not __main__ :(
''',
[1, 11, 12, 14, 16, 17], "")
class GettraceTest(CoverageTest):
"""Tests that we work properly with `sys.gettrace()`."""
def test_round_trip_in_untraced_function(self):
# https://bitbucket.org/ned/coveragepy/issues/575/running-doctest-prevents-complete-coverage
self.make_file("main.py", """import sample""")
self.make_file("sample.py", """\
from swap import swap_it
def doit():
print(3)
swap_it()
print(5)
def doit_soon():
print(7)
doit()
print(9)
print(10)
doit_soon()
print(12)
""")
self.make_file("swap.py", """\
import sys
def swap_it():
sys.settrace(sys.gettrace())
""")
# Use --source=sample to prevent measurement of swap.py.
cov = coverage.Coverage(source=["sample"])
self.start_import_stop(cov, "main")
self.assertEqual(self.stdout(), "10\n7\n3\n5\n9\n12\n")
_, statements, missing, _ = cov.analysis("sample.py")
self.assertEqual(statements, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12])
self.assertEqual(missing, [])
def test_setting_new_trace_function(self):
# https://bitbucket.org/ned/coveragepy/issues/436/disabled-coverage-ctracer-may-rise-from
self.check_coverage('''\
import sys
def tracer(frame, event, arg):
print("%s: %s @ %d" % (event, frame.f_code.co_filename, frame.f_lineno))
return tracer
def begin():
sys.settrace(tracer)
def collect():
t = sys.gettrace()
assert t is tracer, t
def test_unsets_trace():
begin()
collect()
old = sys.gettrace()
test_unsets_trace()
sys.settrace(old)
a = 21
b = 22
''',
lines=[1, 3, 4, 5, 7, 8, 10, 11, 12, 14, 15, 16, 18, 19, 20, 21, 22],
missing="4-5, 11-12",
)
out = self.stdout().replace(self.last_module_name, "coverage_test")
self.assertEqual(
out,
(
"call: coverage_test.py @ 10\n"
"line: coverage_test.py @ 11\n"
"line: coverage_test.py @ 12\n"
"return: coverage_test.py @ 12\n"
),
)
@pytest.mark.expensive
def test_atexit_gettrace(self): # pragma: no metacov
# This is not a test of coverage at all, but of our understanding
# of this edge-case behavior in various Pythons.
if env.METACOV:
self.skipTest("Can't set trace functions during meta-coverage")
self.make_file("atexit_gettrace.py", """\
import atexit, sys
def trace_function(frame, event, arg):
return trace_function
sys.settrace(trace_function)
def show_trace_function():
tfn = sys.gettrace()
if tfn is not None:
tfn = tfn.__name__
print(tfn)
atexit.register(show_trace_function)
# This will show what the trace function is at the end of the program.
""")
status, out = self.run_command_status("python atexit_gettrace.py")
self.assertEqual(status, 0)
if env.PYPY and env.PYPYVERSION >= (5, 4):
# Newer PyPy clears the trace function before atexit runs.
self.assertEqual(out, "None\n")
else:
# Other Pythons leave the trace function in place.
self.assertEqual(out, "trace_function\n")
class ExecTest(CoverageTest):
"""Tests of exec."""
def test_correct_filename(self):
# https://bitbucket.org/ned/coveragepy/issues/380/code-executed-by-exec-excluded-from
# Bug was that exec'd files would have their lines attributed to the
# calling file. Make two files, both with ~30 lines, but no lines in
# common. Line 30 in to_exec.py was recorded as line 30 in main.py,
# but now it's fixed. :)
self.make_file("to_exec.py", """\
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
print("var is {0}".format(var)) # line 31
""")
self.make_file("main.py", """\
namespace = {'var': 17}
with open("to_exec.py") as to_exec_py:
code = compile(to_exec_py.read(), 'to_exec.py', 'exec')
exec(code, globals(), namespace)
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
print("done") # line 35
""")
cov = coverage.Coverage()
self.start_import_stop(cov, "main")
_, statements, missing, _ = cov.analysis("main.py")
self.assertEqual(statements, [1, 2, 3, 4, 35])
self.assertEqual(missing, [])
_, statements, missing, _ = cov.analysis("to_exec.py")
self.assertEqual(statements, [31])
self.assertEqual(missing, [])
class MockingProtectionTest(CoverageTest):
"""Tests about protecting ourselves from aggressive mocking.
https://bitbucket.org/ned/coveragepy/issues/416/coverage-40-is-causing-existing-unit-tests
"""
def test_os_path_exists(self):
# To see if this test still detects the problem, change isolate_module
# in misc.py to simply return its argument. It should fail with a
# StopIteration error.
self.make_file("bug416.py", """\
import os.path
import mock
@mock.patch('os.path.exists')
def test_path_exists(mock_exists):
mock_exists.side_effect = [17]
print("in test")
import bug416a
print(bug416a.foo)
print(os.path.exists("."))
test_path_exists()
""")
self.make_file("bug416a.py", """\
print("bug416a.py")
foo = 23
""")
import py_compile
py_compile.compile("bug416a.py")
out = self.run_command("coverage run bug416.py")
self.assertEqual(out, "in test\nbug416a.py\n23\n17\n")