Allow noqa to apply to lines due to continuation

tests/integration/test_checker.py

@@ -15,7 +15,7 @@ EXPECTED_RESULT_PHYSICAL_LINE = (
     0,
     1,
     'Expected Message',
-    PHYSICAL_LINE,
+    None,
 )
 
 
@@ -153,11 +153,10 @@ def test_line_check_results(plugin_target, len_results):
     """Test the FileChecker class handling results from line checks."""
     file_checker = mock_file_checker_with_plugin(plugin_target)
 
-    # Results will be store in an internal array
+    # Results will be stored in an internal array
     file_checker.run_physical_checks(PHYSICAL_LINE)
-    assert file_checker.results == [
-        EXPECTED_RESULT_PHYSICAL_LINE
-    ] * len_results
+    expected = [EXPECTED_RESULT_PHYSICAL_LINE] * len_results
+    assert file_checker.results == expected
 
 
 PLACEHOLDER_CODE = 'some_line = "of" * code'

tests/integration/test_main.py

@@ -182,6 +182,25 @@ t.py:1:15: E711 comparison to None should be 'if cond is None:'
 '''
 
 
+def test_specific_noqa_on_line_with_continuation(tmpdir, capsys):
+    """See https://gitlab.com/pycqa/flake8/issues/375."""
+    t_py_src = '''\
+from os \\
+    import path  # noqa: F401
+
+x = """
+    trailing whitespace: \n
+"""  # noqa: W291
+'''
+
+    with tmpdir.as_cwd():
+        tmpdir.join('t.py').write(t_py_src)
+        _call_main(['t.py'], retv=0)
+
+    out, err = capsys.readouterr()
+    assert out == err == ''
+
+
 def test_obtaining_args_from_sys_argv_when_not_explicity_provided(capsys):
     """Test that arguments are obtained from 'sys.argv'."""
     with mock.patch('sys.argv', ['flake8', '--help']):

tests/unit/test_file_processor.py

@@ -122,16 +122,56 @@ def test_read_lines_ignores_empty_display_name(
     assert file_processor.filename == 'stdin'
 
 
-def test_line_for(default_options):
+def test_noqa_line_for(default_options):
     """Verify we grab the correct line from the cached lines."""
     file_processor = processor.FileProcessor('-', default_options, lines=[
-        'Line 1',
-        'Line 2',
-        'Line 3',
+        'Line 1\n',
+        'Line 2\n',
+        'Line 3\n',
     ])
 
     for i in range(1, 4):
-        assert file_processor.line_for(i) == 'Line {0}'.format(i)
+        assert file_processor.noqa_line_for(i) == 'Line {0}\n'.format(i)
+
+
+def test_noqa_line_for_continuation(default_options):
+    """Verify that the correct "line" is retrieved for continuation."""
+    src = '''\
+from foo \\
+    import bar  # 2
+
+x = """
+hello
+world
+"""  # 7
+'''
+    lines = src.splitlines(True)
+    file_processor = processor.FileProcessor('-', default_options, lines=lines)
+
+    assert file_processor.noqa_line_for(0) is None
+
+    l_1_2 = 'from foo \\\n    import bar  # 2\n'
+    assert file_processor.noqa_line_for(1) == l_1_2
+    assert file_processor.noqa_line_for(2) == l_1_2
+
+    assert file_processor.noqa_line_for(3) == '\n'
+
+    l_4_7 = 'x = """\nhello\nworld\n"""  # 7\n'
+    for i in (4, 5, 6, 7):
+        assert file_processor.noqa_line_for(i) == l_4_7
+
+    assert file_processor.noqa_line_for(8) is None
+
+
+def test_noqa_line_for_no_eol_at_end_of_file(default_options):
+    """Verify that we properly handle noqa line at the end of the file."""
+    src = 'from foo \\\nimport bar'  # no end of file newline
+    lines = src.splitlines(True)
+    file_processor = processor.FileProcessor('-', default_options, lines=lines)
+
+    l_1_2 = 'from foo \\\nimport bar'
+    assert file_processor.noqa_line_for(1) == l_1_2
+    assert file_processor.noqa_line_for(2) == l_1_2
 
 
 def test_next_line(default_options):