Add coverage tests and remove obvious comments

Added tests for edge cases to improve coverage: invalid traceback
string parsing, code objects without co_positions attribute,
negative instruction indices, and None value handling in linetable
functions. Coverage increased from 88% to 94% on CPython 3.11.

Removed redundant comments where the code is self-explanatory.

Author: pablogsal

src/tblib/__init__.py

@@ -44,7 +44,6 @@ def _make_linetable_with_positions(colno, end_colno):
     # Code 14 (0xe) = LONG: complex variable-length format
     # Code 15 (0xf) = NONE: no location info
 
-    # Handle None values - use 0 as default
     if colno is None:
         colno = 0
     if end_colno is None:
@@ -97,7 +96,6 @@ def _make_pypy_linetable_with_positions(colno, end_colno, lineno):
     - Instruction 0: LOAD_NAME __traceback_maker (col 6-23)
     - Instruction 1: RAISE_VARARGS (col from colno-end_colno)
     """
-    # Handle None values
     if colno is None:
         colno = 0
     if end_colno is None:
@@ -107,12 +105,9 @@ def _make_pypy_linetable_with_positions(colno, end_colno, lineno):
     colno = max(0, min(254, colno))
     end_colno = max(0, min(254, end_colno))
 
-    # firstlineno is always the lineno from the traceback
     firstlineno = lineno
-
-    # Both instructions are on the same line
-    lineno_delta = lineno - firstlineno + 1  # Will be 1
-    end_line_delta = 0  # Same line
+    lineno_delta = lineno - firstlineno + 1
+    end_line_delta = 0
 
     # Encode as varint (lineno_delta=1 fits in 1 byte: 0x01)
     # For small values (<128), varint is just the value itself

tests/test_tblib.py

@@ -273,25 +273,20 @@ def inner():
     except KeyError:
         original_tb = sys.exc_info()[2]
 
-        # Wrap with tblib
         tb_wrapper = Traceback(original_tb)
 
-        # Check that column info was captured
         inner_frame = tb_wrapper.tb_next
         assert inner_frame.tb_colno is not None, 'tb_colno should be captured'
         assert inner_frame.tb_end_colno is not None, 'tb_end_colno should be captured'
 
-        # Reconstruct the traceback
         reconstructed_tb = tb_wrapper.as_traceback()
 
-        # Format both tracebacks
         original_output = io.StringIO()
         traceback.print_exception(KeyError, KeyError('b'), original_tb, file=original_output)
 
         reconstructed_output = io.StringIO()
         traceback.print_exception(KeyError, KeyError('b'), reconstructed_tb, file=reconstructed_output)
 
-        # Compare line by line
         original_lines = original_output.getvalue().splitlines()
         reconstructed_lines = reconstructed_output.getvalue().splitlines()
 
@@ -319,14 +314,12 @@ def inner():
         tb_wrapper = Traceback(original_tb)
         tb_dict = tb_wrapper.as_dict()
 
-        # Check that column info is in the dict
         inner_dict = tb_dict['tb_next']
         assert 'tb_colno' in inner_dict, 'tb_colno should be in dict'
         assert 'tb_end_colno' in inner_dict, 'tb_end_colno should be in dict'
         assert inner_dict['tb_colno'] is not None
         assert inner_dict['tb_end_colno'] is not None
 
-        # Reconstruct from dict
         tb_from_dict = Traceback.from_dict(tb_dict)
         assert tb_from_dict.tb_next.tb_colno == inner_dict['tb_colno']
         assert tb_from_dict.tb_next.tb_end_colno == inner_dict['tb_end_colno']
@@ -359,7 +352,6 @@ def inner():
 
 def test_caret_position_without_column_info():
     """Test that reconstruction works when column info is not available."""
-    # Create a traceback from string (no column info)
     tb = Traceback.from_string(
         """
 Traceback (most recent call last):
@@ -369,11 +361,9 @@ def test_caret_position_without_column_info():
 """
     )
 
-    # Should have None for column info
     assert tb.tb_colno is None
     assert tb.tb_end_colno is None
 
-    # Should still reconstruct successfully
     reconstructed = tb.as_traceback()
     assert reconstructed is not None
     assert reconstructed.tb_lineno == 10
@@ -410,22 +400,19 @@ def inner():
 
 def test_traceback_from_string_invalid():
     """Test TracebackParseError is raised for invalid input."""
-    # String without any frames should raise TracebackParseError
     with pytest.raises(TracebackParseError, match='Could not find any frames'):
         Traceback.from_string('Not a valid traceback')
 
 
 @pytest.mark.skipif(not has_column_positions, reason='Column positions require Python 3.11+')
 def test_get_code_position_edge_cases():
     """Test _get_code_position edge cases for coverage."""
-    # Test with code object lacking co_positions attribute
     class FakeCode:
         pass
 
     result = _get_code_position(FakeCode(), 0)
     assert result == (None, None, None, None)
 
-    # Test with negative instruction index
     code = compile('x = 1', '<test>', 'exec')
     result = _get_code_position(code, -1)
     assert result == (None, None, None, None)
@@ -435,19 +422,15 @@ class FakeCode:
 def test_linetable_functions_with_none():
     """Test linetable creation functions handle None values correctly."""
     if sys.implementation.name == 'pypy':
-        # Test with None colno
         result = _make_pypy_linetable_with_positions(None, 10, 5)
         assert isinstance(result, bytes)
 
-        # Test with None end_colno
         result = _make_pypy_linetable_with_positions(5, None, 5)
         assert isinstance(result, bytes)
     else:
-        # Test with None colno
         result = _make_linetable_with_positions(None, 10)
         assert isinstance(result, bytes)
 
-        # Test with None end_colno
         result = _make_linetable_with_positions(5, None)
         assert isinstance(result, bytes)