path: root/tests/test_concurrency.py

# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt

"""Tests for concurrency libraries."""

import os
import random
import sys
import threading
import time

from flaky import flaky

import coverage
from coverage import env
from coverage.backward import import_local_file
from coverage.files import abs_file

from tests.coveragetest import CoverageTest


# These libraries aren't always available, we'll skip tests if they aren't.

try:
    import multiprocessing
except ImportError:         # pragma: only jython
    multiprocessing = None

try:
    import eventlet
except ImportError:
    eventlet = None

try:
    import gevent
except ImportError:
    gevent = None

try:
    import greenlet
except ImportError:         # pragma: only jython
    greenlet = None


def measurable_line(l):
    """Is this a line of code coverage will measure?

    Not blank, not a comment, and not "else"
    """
    l = l.strip()
    if not l:
        return False
    if l.startswith('#'):
        return False
    if l.startswith('else:'):
        return False
    if env.JYTHON and l.startswith(('try:', 'except:', 'except ', 'break', 'with ')):
        # Jython doesn't measure these statements.
        return False                    # pragma: only jython
    return True


def line_count(s):
    """How many measurable lines are in `s`?"""
    return len(list(filter(measurable_line, s.splitlines())))


def print_simple_annotation(code, linenos):
    """Print the lines in `code` with X for each line number in `linenos`."""
    for lineno, line in enumerate(code.splitlines(), start=1):
        print(" {0} {1}".format("X" if lineno in linenos else " ", line))


class LineCountTest(CoverageTest):
    """Test the helpers here."""

    run_in_temp_dir = False

    def test_line_count(self):
        CODE = """
            # Hey there!
            x = 1
            if x:
                print("hello")
            else:
                print("bye")

            print("done")
            """

        self.assertEqual(line_count(CODE), 5)


# The code common to all the concurrency models.
SUM_RANGE_Q = """
    # Above this will be imports defining queue and threading.

    class Producer(threading.Thread):
        def __init__(self, limit, q):
            threading.Thread.__init__(self)
            self.limit = limit
            self.q = q

        def run(self):
            for i in range(self.limit):
                self.q.put(i)
            self.q.put(None)

    class Consumer(threading.Thread):
        def __init__(self, q, qresult):
            threading.Thread.__init__(self)
            self.q = q
            self.qresult = qresult

        def run(self):
            sum = 0
            while True:
                i = self.q.get()
                if i is None:
                    break
                sum += i
            self.qresult.put(sum)

    def sum_range(limit):
        q = queue.Queue()
        qresult = queue.Queue()
        c = Consumer(q, qresult)
        p = Producer(limit, q)
        c.start()
        p.start()

        p.join()
        c.join()
        return qresult.get()

    # Below this will be something using sum_range.
    """

PRINT_SUM_RANGE = """
    print(sum_range({QLIMIT}))
    """

# Import the things to use threads.
if env.PY2:
    THREAD = """
    import threading
    import Queue as queue
    """
else:
    THREAD = """
    import threading
    import queue
    """

# Import the things to use eventlet.
EVENTLET = """
    import eventlet.green.threading as threading
    import eventlet.queue as queue
    """

# Import the things to use gevent.
GEVENT = """
    from gevent import monkey
    monkey.patch_thread()
    import threading
    import gevent.queue as queue
    """

# Uncomplicated code that doesn't use any of the concurrency stuff, to test
# the simple case under each of the regimes.
SIMPLE = """
    total = 0
    for i in range({QLIMIT}):
        total += i
    print(total)
    """


def cant_trace_msg(concurrency, the_module):
    """What might coverage.py say about a concurrency setting and imported module?"""
    # In the concurrency choices, "multiprocessing" doesn't count, so remove it.
    if "multiprocessing" in concurrency:
        parts = concurrency.split(",")
        parts.remove("multiprocessing")
        concurrency = ",".join(parts)

    if the_module is None:
        # We don't even have the underlying module installed, we expect
        # coverage to alert us to this fact.
        expected_out = (
            "Couldn't trace with concurrency=%s, "
            "the module isn't installed.\n" % concurrency
        )
    elif env.C_TRACER or concurrency == "thread" or concurrency == "":
        expected_out = None
    else:
        expected_out = (
            "Can't support concurrency=%s with PyTracer, "
            "only threads are supported\n" % concurrency
        )
    return expected_out


class ConcurrencyTest(CoverageTest):
    """Tests of the concurrency support in coverage.py."""

    QLIMIT = 1000

    def try_some_code(self, code, concurrency, the_module, expected_out=None):
        """Run some concurrency testing code and see that it was all covered.

        `code` is the Python code to execute.  `concurrency` is the name of
        the concurrency regime to test it under.  `the_module` is the imported
        module that must be available for this to work at all. `expected_out`
        is the text we expect the code to produce.

        """

        self.make_file("try_it.py", code)

        cmd = "coverage run --concurrency=%s try_it.py" % concurrency
        out = self.run_command(cmd)

        expected_cant_trace = cant_trace_msg(concurrency, the_module)

        if expected_cant_trace is not None:
            self.assertEqual(out, expected_cant_trace)
        else:
            # We can fully measure the code if we are using the C tracer, which
            # can support all the concurrency, or if we are using threads.
            if expected_out is None:
                expected_out = "%d\n" % (sum(range(self.QLIMIT)))
            print(code)
            self.assertEqual(out, expected_out)

            # Read the coverage file and see that try_it.py has all its lines
            # executed.
            data = coverage.CoverageData()
            data.read_file(".coverage")

            # If the test fails, it's helpful to see this info:
            fname = abs_file("try_it.py")
            linenos = data.lines(fname)
            print("{0}: {1}".format(len(linenos), linenos))
            print_simple_annotation(code, linenos)

            lines = line_count(code)
            self.assertEqual(data.line_counts()['try_it.py'], lines)

    def test_threads(self):
        code = (THREAD + SUM_RANGE_Q + PRINT_SUM_RANGE).format(QLIMIT=self.QLIMIT)
        self.try_some_code(code, "thread", threading)

    def test_threads_simple_code(self):
        code = SIMPLE.format(QLIMIT=self.QLIMIT)
        self.try_some_code(code, "thread", threading)

    def test_eventlet(self):
        code = (EVENTLET + SUM_RANGE_Q + PRINT_SUM_RANGE).format(QLIMIT=self.QLIMIT)
        self.try_some_code(code, "eventlet", eventlet)

    def test_eventlet_simple_code(self):
        code = SIMPLE.format(QLIMIT=self.QLIMIT)
        self.try_some_code(code, "eventlet", eventlet)

    def test_gevent(self):
        code = (GEVENT + SUM_RANGE_Q + PRINT_SUM_RANGE).format(QLIMIT=self.QLIMIT)
        self.try_some_code(code, "gevent", gevent)

    def test_gevent_simple_code(self):
        code = SIMPLE.format(QLIMIT=self.QLIMIT)
        self.try_some_code(code, "gevent", gevent)

    def test_greenlet(self):
        GREENLET = """\
            from greenlet import greenlet

            def test1(x, y):
                z = gr2.switch(x+y)
                print(z)

            def test2(u):
                print(u)
                gr1.switch(42)

            gr1 = greenlet(test1)
            gr2 = greenlet(test2)
            gr1.switch("hello", " world")
            """
        self.try_some_code(GREENLET, "greenlet", greenlet, "hello world\n42\n")

    def test_greenlet_simple_code(self):
        code = SIMPLE.format(QLIMIT=self.QLIMIT)
        self.try_some_code(code, "greenlet", greenlet)

    def test_bug_330(self):
        BUG_330 = """\
            from weakref import WeakKeyDictionary
            import eventlet

            def do():
                eventlet.sleep(.01)

            gts = WeakKeyDictionary()
            for _ in range(100):
                gts[eventlet.spawn(do)] = True
                eventlet.sleep(.005)

            eventlet.sleep(.1)
            print(len(gts))
            """
        self.try_some_code(BUG_330, "eventlet", eventlet, "0\n")


SQUARE_OR_CUBE_WORK = """
    def work(x):
        # Use different lines in different subprocesses.
        if x % 2:
            y = x*x
        else:
            y = x*x*x
        return y
    """

SUM_RANGE_WORK = """
    def work(x):
        return sum_range((x+1)*100)
    """

MULTI_CODE = """
    # Above this will be a definition of work().
    import multiprocessing
    import os
    import time
    import sys

    def process_worker_main(args):
        # Need to pause, or the tasks go too quickly, and some processes
        # in the pool don't get any work, and then don't record data.
        time.sleep(0.02)
        ret = work(*args)
        return os.getpid(), ret

    if __name__ == "__main__":      # pragma: no branch
        # This if is on a single line so we can get 100% coverage
        # even if we have no arguments.
        if len(sys.argv) > 1: multiprocessing.set_start_method(sys.argv[1])
        pool = multiprocessing.Pool({NPROCS})
        inputs = [(x,) for x in range({UPTO})]
        outputs = pool.imap_unordered(process_worker_main, inputs)
        pids = set()
        total = 0
        for pid, sq in outputs:
            pids.add(pid)
            total += sq
        print("%d pids, total = %d" % (len(pids), total))
        pool.close()
        pool.join()
    """


@flaky(max_runs=10)         # Sometimes a test fails due to inherent randomness. Try more times.
class MultiprocessingTest(CoverageTest):
    """Test support of the multiprocessing module."""

    def setUp(self):
        super(MultiprocessingTest, self).setUp()
        if not multiprocessing:
            self.skipTest("No multiprocessing in this Python")      # pragma: only jython

    def try_multiprocessing_code(
        self, code, expected_out, the_module, concurrency="multiprocessing"
    ):
        """Run code using multiprocessing, it should produce `expected_out`."""
        self.make_file("multi.py", code)
        self.make_file(".coveragerc", """\
            [run]
            concurrency = %s
            source = .
            """ % concurrency)

        if env.PYVERSION >= (3, 4):
            start_methods = ['fork', 'spawn']
        else:
            start_methods = ['']

        for start_method in start_methods:
            if start_method and start_method not in multiprocessing.get_all_start_methods():
                continue

            out = self.run_command("coverage run multi.py %s" % (start_method,))
            expected_cant_trace = cant_trace_msg(concurrency, the_module)

            if expected_cant_trace is not None:
                self.assertEqual(out, expected_cant_trace)
            else:
                self.assertEqual(out.rstrip(), expected_out)

                out = self.run_command("coverage combine")
                self.assertEqual(out, "")
                out = self.run_command("coverage report -m")

                last_line = self.squeezed_lines(out)[-1]
                self.assertRegex(last_line, r"multi.py \d+ 0 100%")

    def test_multiprocessing_simple(self):
        nprocs = 3
        upto = 30
        code = (SQUARE_OR_CUBE_WORK + MULTI_CODE).format(NPROCS=nprocs, UPTO=upto)
        total = sum(x*x if x%2 else x*x*x for x in range(upto))
        expected_out = "{nprocs} pids, total = {total}".format(nprocs=nprocs, total=total)
        self.try_multiprocessing_code(code, expected_out, threading)

    def test_multiprocessing_and_gevent(self):
        nprocs = 3
        upto = 30
        code = (
            SUM_RANGE_WORK + EVENTLET + SUM_RANGE_Q + MULTI_CODE
        ).format(NPROCS=nprocs, UPTO=upto)
        total = sum(sum(range((x + 1) * 100)) for x in range(upto))
        expected_out = "{nprocs} pids, total = {total}".format(nprocs=nprocs, total=total)
        self.try_multiprocessing_code(
            code, expected_out, eventlet, concurrency="multiprocessing,eventlet"
        )

    def try_multiprocessing_code_with_branching(self, code, expected_out):
        """Run code using multiprocessing, it should produce `expected_out`."""
        self.make_file("multi.py", code)
        self.make_file("multi.rc", """\
            [run]
            concurrency = multiprocessing
            branch = True
            """)

        if env.PYVERSION >= (3, 4):
            start_methods = ['fork', 'spawn']
        else:
            start_methods = ['']

        for start_method in start_methods:
            if start_method and start_method not in multiprocessing.get_all_start_methods():
                continue

            out = self.run_command("coverage run --rcfile=multi.rc multi.py %s" % (start_method,))
            self.assertEqual(out.rstrip(), expected_out)

            out = self.run_command("coverage combine")
            self.assertEqual(out, "")
            out = self.run_command("coverage report -m")

            last_line = self.squeezed_lines(out)[-1]
            self.assertRegex(last_line, r"multi.py \d+ 0 \d+ 0 100%")

    def test_multiprocessing_with_branching(self):
        nprocs = 3
        upto = 30
        code = (SQUARE_OR_CUBE_WORK + MULTI_CODE).format(NPROCS=nprocs, UPTO=upto)
        total = sum(x*x if x%2 else x*x*x for x in range(upto))
        expected_out = "{nprocs} pids, total = {total}".format(nprocs=nprocs, total=total)
        self.try_multiprocessing_code_with_branching(code, expected_out)


def test_coverage_stop_in_threads():
    has_started_coverage = []
    has_stopped_coverage = []

    def run_thread():
        """Check that coverage is stopping properly in threads."""
        deadline = time.time() + 5
        ident = threading.currentThread().ident
        if sys.gettrace() is not None:
            has_started_coverage.append(ident)
        while sys.gettrace() is not None:
            # Wait for coverage to stop
            time.sleep(0.01)
            if time.time() > deadline:
                return
        has_stopped_coverage.append(ident)

    cov = coverage.coverage()
    cov.start()

    t = threading.Thread(target=run_thread)
    t.start()

    time.sleep(0.1)
    cov.stop()
    time.sleep(0.1)

    assert has_started_coverage == [t.ident]
    assert has_stopped_coverage == [t.ident]
    t.join()


def test_thread_safe_save_data(tmpdir):
    # Non-regression test for:
    # https://bitbucket.org/ned/coveragepy/issues/581

    # Create some Python modules and put them in the path
    modules_dir = tmpdir.mkdir('test_modules')
    module_names = ["m{0:03d}".format(i) for i in range(1000)]
    for module_name in module_names:
        modules_dir.join(module_name + ".py").write("def f(): pass\n")

    # Shared variables for threads
    should_run = [True]
    imported = []

    old_dir = os.getcwd()
    os.chdir(modules_dir.strpath)
    try:
        # Make sure that all dummy modules can be imported.
        for module_name in module_names:
            import_local_file(module_name)

        def random_load():
            """Import modules randomly to stress coverage."""
            while should_run[0]:
                module_name = random.choice(module_names)
                mod = import_local_file(module_name)
                mod.f()
                imported.append(mod)

        # Spawn some threads with coverage enabled and attempt to read the
        # results right after stopping coverage collection with the threads
        #  still running.
        duration = 0.01
        for _ in range(3):
            cov = coverage.coverage()
            cov.start()

            threads = [threading.Thread(target=random_load) for _ in range(10)]
            should_run[0] = True
            for t in threads:
                t.start()

            time.sleep(duration)

            cov.stop()

            # The following call used to crash with running background threads.
            cov.get_data()

            # Stop the threads
            should_run[0] = False
            for t in threads:
                t.join()

            if (not imported) and duration < 10:
                duration *= 2

    finally:
        os.chdir(old_dir)
        should_run[0] = False