Merge branch 'master' into clearer_unittest_failure_message

4 files changed, 389 insertions, 2 deletions

diff --git a/pylint/lint/__init__.py b/pylint/lint/__init__.py
index 7cd19fd96..b2421cafa 100644
--- a/pylint/lint/__init__.py
+++ b/pylint/lint/__init__.py
@@ -72,7 +72,7 @@
 """
 import sys
 
-from pylint.lint.check_parallel import check_parallel
+from pylint.lint.parallel import check_parallel
 from pylint.lint.pylinter import PyLinter
 from pylint.lint.report_functions import (
     report_messages_by_module_stats,
diff --git a/pylint/lint/check_parallel.py b/pylint/lint/parallel.py
index b9257191c..b9257191c 100644
--- a/pylint/lint/check_parallel.py
+++ b/pylint/lint/parallel.py
diff --git a/pylint/lint/pylinter.py b/pylint/lint/pylinter.py
index 1ce84a523..63ba9b02f 100644
--- a/pylint/lint/pylinter.py
+++ b/pylint/lint/pylinter.py
@@ -18,7 +18,7 @@ from astroid.builder import AstroidBuilder
 
 from pylint import checkers, config, exceptions, interfaces, reporters
 from pylint.constants import MAIN_CHECKER_NAME, MSG_TYPES
-from pylint.lint.check_parallel import check_parallel
+from pylint.lint.parallel import check_parallel
 from pylint.lint.report_functions import (
     report_messages_by_module_stats,
     report_messages_stats,
diff --git a/tests/test_check_parallel.py b/tests/test_check_parallel.py
new file mode 100644
index 000000000..f44ce666d
--- /dev/null
+++ b/tests/test_check_parallel.py
@@ -0,0 +1,387 @@
+"""Puts the check_parallel system under test"""
+# Copyright (c) 2020 Frank Harrison <doublethefish@gmail.com>
+
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
+
+# pylint: disable=protected-access,missing-function-docstring,no-self-use
+
+import collections
+import os
+
+import pytest
+
+import pylint.interfaces
+import pylint.lint.parallel
+from pylint.checkers.base_checker import BaseChecker
+from pylint.lint import PyLinter
+from pylint.lint.parallel import _worker_check_single_file as worker_check_single_file
+from pylint.lint.parallel import _worker_initialize as worker_initialize
+from pylint.lint.parallel import check_parallel
+from pylint.testutils import TestReporter as Reporter
+
+
+def _gen_file_data(idx=0):
+    """Generates a file to use as a stream"""
+    filepath = os.path.abspath(
+        os.path.join(os.path.dirname(__file__), "input", "similar1")
+    )
+    file_data = (
+        "--test-file_data-name-%d--" % idx,
+        filepath,
+        "--test-file_data-modname-%d--" % idx,
+    )
+    return file_data
+
+
+def _gen_file_datas(count=1):
+    return [_gen_file_data(idx) for idx in range(count)]
+
+
+class SequentialTestChecker(BaseChecker):
+    """A checker that does not need to consolidate data across run invocations"""
+
+    __implements__ = (pylint.interfaces.IRawChecker,)
+
+    name = "sequential-checker"
+    test_data = "sequential"
+    msgs = {
+        "R9999": (
+            "Test",
+            "sequential-test-check",
+            "Some helpful text.",
+        )
+    }
+
+    def __init__(self, linter, *args, **kwargs):
+        super().__init__(linter, *args, **kwargs)
+        self.data = []
+        self.linter = linter
+
+    def process_module(self, _astroid):
+        """Called once per stream/file/astroid object"""
+        # record the number of invocations with the data object
+        record = self.test_data + str(len(self.data))
+        self.data.append(record)
+
+
+class ExtraSequentialTestChecker(SequentialTestChecker):
+    """A checker that does not need to consolidate data across run invocations"""
+
+    name = "extra-sequential-checker"
+    test_data = "extra-sequential"
+
+
+class ThirdSequentialTestChecker(SequentialTestChecker):
+    """A checker that does not need to consolidate data across run invocations"""
+
+    name = "third-sequential-checker"
+    test_data = "third-sequential"
+
+
+class TestCheckParallelFramework:
+    """Tests the check_parallel() function's framework"""
+
+    def setup_class(self):
+        self._prev_global_linter = pylint.lint.parallel._worker_linter
+
+    def teardown_class(self):
+        pylint.lint.parallel._worker_linter = self._prev_global_linter
+
+    def test_worker_initialize(self):
+        linter = PyLinter(reporter=Reporter())
+        worker_initialize(linter=linter)
+        assert pylint.lint.parallel._worker_linter == linter
+
+    def test_worker_check_single_file_uninitialised(self):
+        pylint.lint.parallel._worker_linter = None
+        with pytest.raises(  # Objects that do not match the linter interface will fail
+            AttributeError, match="'NoneType' object has no attribute 'open'"
+        ):
+            worker_check_single_file(_gen_file_data())
+
+    def test_worker_check_single_file_no_checkers(self):
+        linter = PyLinter(reporter=Reporter())
+        worker_initialize(linter=linter)
+        (name, _, _, msgs, stats, msg_status) = worker_check_single_file(
+            _gen_file_data()
+        )
+        assert name == "--test-file_data-name-0--"
+        assert [] == msgs
+        no_errors_status = 0
+        assert no_errors_status == msg_status
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                }
+            },
+            "by_msg": {},
+            "convention": 0,
+            "error": 0,
+            "fatal": 0,
+            "info": 0,
+            "refactor": 0,
+            "statement": 18,
+            "warning": 0,
+        } == stats
+
+    def test_worker_check_sequential_checker(self):
+        """Same as test_worker_check_single_file_no_checkers with SequentialTestChecker"""
+        linter = PyLinter(reporter=Reporter())
+        worker_initialize(linter=linter)
+
+        # Add the only checker we care about in this test
+        linter.register_checker(SequentialTestChecker(linter))
+
+        (name, _, _, msgs, stats, msg_status) = worker_check_single_file(
+            _gen_file_data()
+        )
+
+        # Ensure we return the same data as the single_file_no_checkers test
+        assert name == "--test-file_data-name-0--"
+        assert [] == msgs
+        no_errors_status = 0
+        assert no_errors_status == msg_status
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                }
+            },
+            "by_msg": {},
+            "convention": 0,
+            "error": 0,
+            "fatal": 0,
+            "info": 0,
+            "refactor": 0,
+            "statement": 18,
+            "warning": 0,
+        } == stats
+
+
+class TestCheckParallel:
+    """Tests the check_parallel() function"""
+
+    def test_sequential_checkers_work(self):
+        """Tests original basic types of checker works as expected in -jN
+
+        This means that a sequential checker should return the same data for a given
+        file-stream irrespective of whether its run in -j1 or -jN
+        """
+        linter = PyLinter(reporter=Reporter())
+
+        # Add a sequential checker to ensure it records data against some streams
+        linter.register_checker(SequentialTestChecker(linter))
+        linter.enable("R9999")
+
+        # Create a dummy file, the actual contents of which will be ignored by the
+        # register test checkers, but it will trigger at least a single-job to be run.
+        single_file_container = _gen_file_datas(count=1)
+
+        # Invoke the lint process in a multiprocess way, although we only specify one
+        # job.
+        check_parallel(linter, jobs=1, files=single_file_container, arguments=None)
+        assert len(linter.get_checkers()) == 2, (
+            "We should only have the 'master' and 'sequential-checker' "
+            "checkers registered"
+        )
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                }
+            },
+            "by_msg": {},
+            "convention": 0,
+            "error": 0,
+            "fatal": 0,
+            "info": 0,
+            "refactor": 0,
+            "statement": 18,
+            "warning": 0,
+        } == linter.stats
+
+        # now run the regular mode of checking files and check that, in this proc, we
+        # collect the right data
+        filepath = single_file_container[0][1]  # get the filepath element
+        linter.check(filepath)
+        assert {
+            "by_module": {
+                "input.similar1": {  # module is the only change from previous
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                }
+            },
+            "by_msg": {},
+            "convention": 0,
+            "error": 0,
+            "fatal": 0,
+            "info": 0,
+            "refactor": 0,
+            "statement": 18,
+            "warning": 0,
+        } == linter.stats
+
+    def test_invoke_single_job(self):
+        """Tests basic checkers functionality using just a single workderdo
+
+        This is *not* the same -j1 and does not happen under normal operation"""
+        linter = PyLinter(reporter=Reporter())
+
+        linter.register_checker(SequentialTestChecker(linter))
+
+        # Create a dummy file, the actual contents of which will be ignored by the
+        # register test checkers, but it will trigger at least a single-job to be run.
+        single_file_container = _gen_file_datas(count=1)
+
+        # Invoke the lint process in a multiprocess way, although we only specify one
+        # job.
+        check_parallel(linter, jobs=1, files=single_file_container, arguments=None)
+
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                }
+            },
+            "by_msg": collections.Counter(),
+            "convention": 0,
+            "error": 0,
+            "fatal": 0,
+            "info": 0,
+            "refactor": 0,
+            "statement": 18,
+            "warning": 0,
+        } == linter.stats
+        assert linter.msg_status == 0, "We expect a single-file check to exit cleanly"
+
+    @pytest.mark.parametrize(
+        "num_files,num_jobs,num_checkers",
+        [
+            (1, 2, 1),
+            (1, 2, 2),
+            (1, 2, 3),
+            (2, 2, 1),
+            (2, 2, 2),
+            (2, 2, 3),
+            (3, 2, 1),
+            (3, 2, 2),
+            (3, 2, 3),
+            (3, 1, 1),
+            (3, 1, 2),
+            (3, 1, 3),
+            (3, 5, 1),
+            (3, 5, 2),
+            (3, 5, 3),
+            (10, 2, 1),
+            (10, 2, 2),
+            (10, 2, 3),
+            (2, 10, 1),
+            (2, 10, 2),
+            (2, 10, 3),
+        ],
+    )
+    def test_compare_workers_to_single_proc(self, num_files, num_jobs, num_checkers):
+        """Compares the 3 key parameters for check_parallel() produces the same results
+
+        The intent here is to ensure that the check_parallel() operates on each file,
+        without ordering issues, irrespective of the number of workers used and the
+        number of checkers applied.
+
+        This test becomes more important if we want to change how we parametrise the
+        checkers, for example if we aim to batch the files across jobs."""
+
+        # define the stats we expect to get back from the runs, these should only vary
+        # with the number of files.
+        expected_stats = {
+            "by_module": {
+                "--test-file_data-name-%d--"
+                % idx: {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                }
+                for idx in range(num_files)
+            },
+            "by_msg": {},
+            "convention": 0,
+            "error": 0,
+            "fatal": 0,
+            "info": 0,
+            "refactor": 0,
+            "statement": 18 * num_files,
+            "warning": 0,
+        }
+
+        file_infos = _gen_file_datas(num_files)
+
+        # Loop for single-proc and mult-proc so we can ensure the same linter-config
+        for do_single_proc in range(2):
+            linter = PyLinter(reporter=Reporter())
+
+            # Assign between 1 and 3 checkers to the linter, they should not change the
+            # results of the lint
+            linter.register_checker(SequentialTestChecker(linter))
+            if num_checkers > 1:
+                linter.register_checker(ExtraSequentialTestChecker(linter))
+            if num_checkers > 2:
+                linter.register_checker(ThirdSequentialTestChecker(linter))
+
+            if do_single_proc:
+                # establish the baseline
+                assert (
+                    linter.config.jobs == 1
+                ), "jobs>1 are ignored when calling _check_files"
+                linter._check_files(linter.get_ast, file_infos)
+                assert linter.msg_status == 0, "We should not fail the lint"
+                stats_single_proc = linter.stats
+            else:
+                check_parallel(
+                    linter,
+                    jobs=num_jobs,
+                    files=file_infos,
+                    arguments=None,
+                )
+                stats_check_parallel = linter.stats
+                assert linter.msg_status == 0, "We should not fail the lint"
+
+        assert (
+            stats_single_proc == stats_check_parallel
+        ), "Single-proc and check_parallel() should return the same thing"
+        assert (
+            stats_check_parallel == expected_stats
+        ), "The lint is returning unexpected results, has something changed?"