Add more tests around the processor module

2 files changed, 49 insertions, 2 deletions

diff --git a/flake8/processor.py b/flake8/processor.py
index bf96c7a..e71784c 100644
--- a/flake8/processor.py
+++ b/flake8/processor.py
@@ -370,6 +370,8 @@ def log_token(log, token):
                 token[1]))
 
 
+# NOTE(sigmavirus24): This was taken wholesale from
+# https://github.com/PyCQA/pycodestyle
 def expand_indent(line):
     r"""Return the amount of indentation.
 
@@ -397,6 +399,9 @@ def expand_indent(line):
     return result
 
 
+# NOTE(sigmavirus24): This was taken wholesale from
+# https://github.com/PyCQA/pycodestyle. The in-line comments were edited to be
+# more descriptive.
 def mutate_string(text):
     """Replace contents with 'xxx' to prevent syntax matching.
 
@@ -407,10 +412,12 @@ def mutate_string(text):
     >>> mute_string("r'abc'")
     "r'xxx'"
     """
-    # String modifiers (e.g. u or r)
+    # NOTE(sigmavirus24): If there are string modifiers (e.g., b, u, r)
+    # use the last "character" to determine if we're using single or double
+    # quotes and then find the first instance of it
     start = text.index(text[-1]) + 1
     end = len(text) - 1
-    # Triple quotes
+    # Check for triple-quoted strings
     if text[-3:] in ('"""', "'''"):
         start += 2
         end -= 2
diff --git a/tests/unit/test_file_processor.py b/tests/unit/test_file_processor.py
index 027e74b..50c5fee 100644
--- a/tests/unit/test_file_processor.py
+++ b/tests/unit/test_file_processor.py
@@ -209,3 +209,43 @@ def test_inside_multiline():
         assert file_processor.line_number == 10
 
     assert file_processor.multiline is False
+
+
+@pytest.mark.parametrize('string, expected', [
+    ('""', '""'),
+    ("''", "''"),
+    ('"a"', '"x"'),
+    ("'a'", "'x'"),
+    ('"x"', '"x"'),
+    ("'x'", "'x'"),
+    ('"abcdef"', '"xxxxxx"'),
+    ("'abcdef'", "'xxxxxx'"),
+    ('""""""', '""""""'),
+    ("''''''", "''''''"),
+    ('"""a"""', '"""x"""'),
+    ("'''a'''", "'''x'''"),
+    ('"""x"""', '"""x"""'),
+    ("'''x'''", "'''x'''"),
+    ('"""abcdef"""', '"""xxxxxx"""'),
+    ("'''abcdef'''", "'''xxxxxx'''"),
+    ('"""xxxxxx"""', '"""xxxxxx"""'),
+    ("'''xxxxxx'''", "'''xxxxxx'''"),
+])
+def test_mutate_string(string, expected):
+    """Verify we appropriately mutate the string to sanitize it."""
+    actual = processor.mutate_string(string)
+    assert expected == actual
+
+
+@pytest.mark.parametrize('string, expected', [
+    ('    ', 4),
+    ('      ', 6),
+    ('\t', 8),
+    ('\t\t', 16),
+    ('       \t', 8),
+    ('        \t', 16),
+])
+def test_expand_indent(string, expected):
+    """Verify we correctly measure the amount of indentation."""
+    actual = processor.expand_indent(string)
+    assert expected == actual