Adding whitespace escaping on difference display

AUTHORS

@@ -284,6 +284,7 @@ Nicolas Delaby
 Nikolay Kondratyev
 Nipunn Koorapati
 Oleg Pidsadnyi
+Oleg Plisov
 Oleg Sushchenko
 Olga Matoula
 Oliver Bestwalter

changelog/10704.improvement.rst

@@ -0,0 +1 @@
+Terminal outputting string difference will now escape whitespace characters if those are the difference

src/_pytest/assertion/util.py

@@ -305,10 +305,22 @@ def _diff_text(left: str, right: str, verbose: int = 0) -> List[str]:
                 left = left[:-i]
                 right = right[:-i]
     keepends = True
+    diffspace = False
+    for i in range(min(len(left), len(right))):
+        if left[i] != right[i]:
+            if left[i].isspace() and right[i].isspace():
+                diffspace = True  # Check if difference in strings is whitespace symbol
+                break
     if left.isspace() or right.isspace():
         left = repr(str(left))
         right = repr(str(right))
         explanation += ["Strings contain only whitespace, escaping them using repr()"]
+    elif diffspace:
+        left = repr(str(left))
+        right = repr(str(right))
+        explanation += [
+            "Strings are different by whitespaces, escaping them using repr()"
+        ]
     # "right" is the expected base against which we compare "left",
     # see https://github.com/pytest-dev/pytest/issues/3333
     explanation += [

testing/test_error_diffs.py

@@ -262,6 +262,20 @@ TESTCASES = [
         """,
         id="Compare attrs classes",
     ),
+    pytest.param(
+        """
+        def test_this():
+            assert "word\t" == "word    "
+        """,
+        """
+        >       assert "word\t" == "word    "
+        E       AssertionError: assert 'word\\t' == 'word    '
+        E         Strings are different by whitespaces, escaping them using repr()
+        E         - 'word    '
+        E         + 'word\\t'
+        """,
+        id="Compare whitespaces",
+    ),
 ]