Add --bug-report flag to help bug reporters

When invoked it will print out JSON that has all of the debugging
information needed by the maintainers to diagnose or reproduce a bug.

Closes #207

1 files changed, 86 insertions, 0 deletions

diff --git a/tests/unit/test_debug.py b/tests/unit/test_debug.py
new file mode 100644
index 0000000..dbafe2e
--- /dev/null
+++ b/tests/unit/test_debug.py
@@ -0,0 +1,86 @@
+"""Tests for our debugging module."""
+import mock
+import pytest
+import setuptools
+
+from flake8.main import debug
+
+
+def test_dependencies():
+    """Verify that we format our dependencies appropriately."""
+    expected = [{'dependency': 'setuptools',
+                 'version': setuptools.__version__}]
+    assert expected == debug.dependencies()
+
+
+@pytest.mark.parametrize('plugins, expected', [
+    ([], []),
+    ([('pycodestyle', '2.0.0')], [{'plugin': 'pycodestyle',
+                                   'version': '2.0.0'}]),
+    ([('pycodestyle', '2.0.0'), ('mccabe', '0.5.9')],
+        [{'plugin': 'mccabe', 'version': '0.5.9'},
+         {'plugin': 'pycodestyle', 'version': '2.0.0'}]),
+])
+def test_plugins_from(plugins, expected):
+    """Test that we format plugins appropriately."""
+    option_manager = mock.Mock(registered_plugins=set(plugins))
+    assert expected == debug.plugins_from(option_manager)
+
+
+@mock.patch('platform.python_implementation', return_value='CPython')
+@mock.patch('platform.python_version', return_value='3.5.3')
+@mock.patch('platform.system', return_value='Linux')
+def test_information(system, pyversion, pyimpl):
+    """Verify that we return all the information we care about."""
+    expected = {
+        'version': '3.1.0',
+        'plugins': [{'plugin': 'mccabe', 'version': '0.5.9'},
+                    {'plugin': 'pycodestyle', 'version': '2.0.0'}],
+        'dependencies': [{'dependency': 'setuptools',
+                          'version': setuptools.__version__}],
+        'platform': {
+            'python_implementation': 'CPython',
+            'python_version': '3.5.3',
+            'system': 'Linux',
+        },
+    }
+    option_manager = mock.Mock(
+        registered_plugins=set([('pycodestyle', '2.0.0'),
+                                ('mccabe', '0.5.9')]),
+        version='3.1.0',
+    )
+    assert expected == debug.information(option_manager)
+    pyimpl.assert_called_once_with()
+    pyversion.assert_called_once_with()
+    system.assert_called_once_with()
+
+
+@mock.patch('flake8.main.debug.print')
+@mock.patch('flake8.main.debug.information', return_value={})
+@mock.patch('json.dumps', return_value='{}')
+def test_print_information_no_plugins(dumps, information, print_mock):
+    """Verify we print and exit only when we have plugins."""
+    plugins = []
+    option_manager = mock.Mock(registered_plugins=set(plugins))
+    assert debug.print_information(
+        None, None, None, None, option_manager=option_manager,
+    ) is None
+    assert dumps.called is False
+    assert information.called is False
+    assert print_mock.called is False
+
+
+@mock.patch('flake8.main.debug.print')
+@mock.patch('flake8.main.debug.information', return_value={})
+@mock.patch('json.dumps', return_value='{}')
+def test_print_information(dumps, information, print_mock):
+    """Verify we print and exit only when we have plugins."""
+    plugins = [('pycodestyle', '2.0.0'), ('mccabe', '0.5.9')]
+    option_manager = mock.Mock(registered_plugins=set(plugins))
+    with pytest.raises(SystemExit):
+        debug.print_information(
+            None, None, None, None, option_manager=option_manager,
+        )
+    print_mock.assert_called_once_with('{}')
+    dumps.assert_called_once_with({}, indent=2, sort_keys=True)
+    information.assert_called_once_with(option_manager)