annotate.py: Add line_is_whitespace() and lightly test it

src/diffannotator/annotate.py

@@ -288,6 +288,19 @@ def line_is_empty(tokens_list: Iterable[tuple]) -> bool:
     return len(tokens_list) == 1 and (tokens_list[0][2] == '\n' or tokens_list[0][2] == '\r\n')
 
 
+def line_is_whitespace(tokens_list: Iterable[tuple]) -> bool:
+    """Given results of parsing a line, find if it consists only of whitespace tokens
+
+    :param tokens_list: An iterable of (index, token_type, text_fragment) tuples,
+        supposedly created by parsing some line of source code text
+    :return: Whether set of tokens in `tokens_list` are all
+        whitespace tokens
+    """
+    return all([token_type in Token.Text.Whitespace or
+                token_type in Token.Text and text_fragment.isspace()
+                for _, token_type, text_fragment in tokens_list])
+
+
 def line_is_comment(tokens_list: Iterable[tuple]) -> bool:
     """Given results of parsing line, find if it is comment
 

tests/test_annotate.py

@@ -13,7 +13,8 @@
 from diffannotator.annotate import (split_multiline_lex_tokens, line_ends_idx,
                                     group_tokens_by_line, front_fill_gaps, deep_update,
                                     clean_text, line_is_comment, line_is_empty, annotate_single_diff,
-                                    Bug, BugDataset, AnnotatedPatchedFile, AnnotatedHunk, AnnotatedPatchSet)
+                                    Bug, BugDataset, AnnotatedPatchedFile, AnnotatedHunk, AnnotatedPatchSet,
+                                    line_is_whitespace)
 from diffannotator.utils.git import GitRepo, DiffSide, ChangeSet
 from .conftest import count_pm_lines
 
@@ -1017,6 +1018,17 @@ def test__line_is__functions(self):
                         if k != 0 and k != len(actual) - 2]), \
             "all lines but first and next to last line in example code are not empty"
 
+        actual = {
+            i: line_is_whitespace(line_tokens)
+            for i, line_tokens in tokens_grouped.items()
+        }
+
+        #print("{{{")
+        #for i, code_line in enumerate(example_C_code.splitlines(keepends=False)):
+        #    print(f"{i:d}: {actual[i]!s:5}:{code_line}", end=':\n')
+        #print("{{{")
 
+        assert actual[0] and actual[5], \
+            "very basic test for whitespace-only lines (and empty lines)"
 
 # end of test_annotate.py