diff --git a/tests/test_check_parallel.py b/tests/test_check_parallel.py
new file mode 100644
index 00000000000..bcadfa3a703
--- /dev/null
+++ b/tests/test_check_parallel.py
@@ -0,0 +1,548 @@
+""" 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
+
+from pylint.checkers.base_checker import BaseChecker
+import pylint.interfaces
+from pylint.lint import (
+    check_parallel,
+    PyLinter,
+    _worker_initialize as worker_initialize,
+    _worker_check_single_file as worker_check_single_file,
+)
+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--",
+    )
+    return file_data
+
+
+def _gen_file_datas(count=1):
+    file_infos = [_gen_file_data(idx) for idx in range(count)]
+    return file_infos
+
+
+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 TestCheckParallelFramework:
+    """ Tests the check_parallel() function's framework """
+
+    def setUp(self):
+        self._prev_global_linter = pylint.lint._worker_linter
+
+    def tearDown(self):
+        pylint.lint._worker_linter = self._prev_global_linter
+
+    def test_worker_initialize(self):
+        linter = PyLinter(reporter=Reporter())
+        worker_initialize(linter=linter)
+        assert pylint.lint._worker_linter == linter
+
+    def test_worker_check_single_file_uninitialised(self):
+        pylint.lint._worker_linter = None
+        with pytest.raises(AttributeError):
+            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"
+
+    def test_multiple_jobs_single_file(self):
+        """Tests that multiple jobs return a single result for a single file """
+        linter = PyLinter(reporter=Reporter())
+
+        # Add a sequential checker to ensure something runs
+        linter.register_checker(SequentialTestChecker(linter))
+
+        # Create a dummy files that we will "test"
+        files = _gen_file_datas(count=1)
+
+        # Invoke the lint checks via check_parallel
+        check_parallel(linter, jobs=2, files=files, 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": {},
+            "convention": 0,
+            "error": 0,
+            "fatal": 0,
+            "info": 0,
+            "refactor": 0,
+            "statement": 18,
+            "warning": 0,
+        } == linter.stats
+        assert linter.msg_status == 0
+
+    def test_multiple_files_single_job(self):
+        """Tests that multiple files return multiple results """
+        linter = PyLinter(reporter=Reporter())
+        linter.register_checker(SequentialTestChecker(linter))
+
+        # Create some dummy files that we will "test"
+        num_files = 10
+        files = _gen_file_datas(count=num_files)
+
+        # Invoke the lint checks via check_parallel
+        check_parallel(linter, jobs=1, files=files, arguments=None)
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-1--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-2--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-3--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-4--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-5--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-6--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-7--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-8--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-9--": {
+                    "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": 180,
+            "warning": 0,
+        } == linter.stats
+        assert linter.msg_status == 0
+
+    def test_2_files_2_jobs(self):
+        """Tests that multiple files return multiple results """
+        linter = PyLinter(reporter=Reporter())
+        linter.register_checker(SequentialTestChecker(linter))
+
+        # Create some dummy files that we will "test"
+        files = _gen_file_datas(count=2)
+
+        # Invoke the lint checks via check_parallel
+        check_parallel(linter, jobs=2, files=files, arguments=None)
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-1--": {
+                    "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": 36,
+            "warning": 0,
+        } == linter.stats
+        assert linter.msg_status == 0
+
+    def test_3_files_2_jobs(self):
+        """Tests that multiple files return multiple results """
+        linter = PyLinter(reporter=Reporter())
+        linter.register_checker(SequentialTestChecker(linter))
+
+        # Create some dummy files that we will "test"
+        files = _gen_file_datas(count=3)
+
+        # Invoke the lint checks via check_parallel
+        check_parallel(linter, jobs=2, files=files, arguments=None)
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-1--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-2--": {
+                    "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": 54,
+            "warning": 0,
+        } == linter.stats
+        assert linter.msg_status == 0, "Did not exit cleanly!"
+
+    def test_2_files_3_jobs(self):
+        """Tests that multiple files return multiple results """
+        linter = PyLinter(reporter=Reporter())
+        linter.register_checker(SequentialTestChecker(linter))
+
+        # Create some dummy files that we will "test"
+        files = _gen_file_datas(count=2)
+
+        # Invoke the lint checks via check_parallel
+        check_parallel(linter, jobs=3, files=files, arguments=None)
+        assert {
+            "by_module": {
+                "--test-file_data-name-0--": {
+                    "convention": 0,
+                    "error": 0,
+                    "fatal": 0,
+                    "info": 0,
+                    "refactor": 0,
+                    "statement": 18,
+                    "warning": 0,
+                },
+                "--test-file_data-name-1--": {
+                    "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": 36,
+            "warning": 0,
+        } == linter.stats
+        assert linter.msg_status == 0