Reduce and tighten comments and docstrings across the test suite (#6429)

* Reduce and tighten comments and docstrings in tests

Shorten verbose comments and docstrings across the test suite without
changing any test logic. Remove narration that restates the next line,
collapse long module and test docstrings to a single line, and drop banner
separators. Keep regression context (issue and PR references, run ids),
skip reasons, mocking and timing rationale, license headers, lint and type
directives, and commented-out code.

Comments and docstrings only: an AST signature check confirms no code,
assertions, or string literals changed, and the suite byte-compiles cleanly.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

tests/saving/test_save_subprocess_utf8_encoding.py

@@ -13,26 +13,11 @@
 
 """Regression tests for unslothai/unsloth#2660.
 
-On Windows the default text encoding is the locale code page (e.g. cp1252),
-not UTF-8. ``subprocess.Popen`` / ``subprocess.run`` opened in text mode
-(``text=True`` / ``universal_newlines=True``) without an explicit
-``encoding`` therefore decode child-process output with cp1252. When
-llama.cpp / Ollama emit a byte that is undefined in cp1252 (e.g. ``0x9d``,
-which appears inside the UTF-8 encoding of common punctuation and box-drawing
-glyphs), the read raises ``UnicodeDecodeError`` and aborts the GGUF export.
-
-Two checks:
-
-* ``test_save_subprocess_text_calls_declare_utf8_encoding`` -- a source-level
-  drift detector. It parses ``unsloth/save.py`` (no import, so it runs under
-  the GPU/torch-free harness) and fails if any text-mode subprocess call is
-  missing ``encoding="utf-8"``. This is the regression guard: it is red
-  before the fix and green after.
-* ``test_utf8_replace_decodes_non_cp1252_subprocess_output`` -- a behavioural
-  check that documents the bug and the fix deterministically on any platform:
-  raw child output that is invalid under cp1252 raises, while the
-  ``encoding="utf-8", errors="replace"`` kwargs used by the fix read it
-  cleanly.
+On Windows, text-mode subprocess calls without explicit encoding decode child
+output as cp1252, raising UnicodeDecodeError on UTF-8 bytes undefined there
+(e.g. 0x9d) and aborting GGUF export. A source-level drift check asserts save.py
+pins encoding="utf-8" on every text-mode call; a behavioural check reproduces
+the cp1252 failure and confirms the utf-8/replace fix reads it cleanly.
 """
 
 from __future__ import annotations
@@ -84,9 +69,8 @@ def _collect_text_mode_subprocess_calls() -> list[ast.Call]:
 
 
 def test_text_mode_subprocess_calls_exist():
-    """Guard the guard: if save.py stops using text-mode subprocess calls the
-    drift test below would vacuously pass, so make sure we are actually
-    inspecting something."""
+    """Guard the guard: ensure save.py still has text-mode subprocess calls so
+    the drift test below isn't vacuously passing."""
     calls = _collect_text_mode_subprocess_calls()
     assert len(calls) >= 6, (
         f"Expected several text-mode subprocess calls in {SAVE_PY.name}, "
@@ -95,11 +79,8 @@ def test_text_mode_subprocess_calls_exist():
 
 
 def test_save_subprocess_text_calls_declare_utf8_encoding():
-    """Every text-mode subprocess call in save.py must pin encoding='utf-8'.
-
-    Without it, reading llama.cpp/Ollama output crashes on Windows (cp1252).
-    Fails before the #2660 fix, passes after.
-    """
+    """Every text-mode subprocess call in save.py must pin encoding='utf-8'
+    (else Windows cp1252 crashes reading child output; #2660 fix)."""
     offenders = []
     for node in _collect_text_mode_subprocess_calls():
         enc = _kw(node, "encoding")
@@ -115,14 +96,10 @@ def test_save_subprocess_text_calls_declare_utf8_encoding():
 
 
 def test_utf8_replace_decodes_non_cp1252_subprocess_output():
-    """Document the failure and the fix with a real subprocess.
-
-    The child emits U+201D (right double quote), whose UTF-8 encoding
-    ``E2 80 9D`` contains byte 0x9D -- undefined in cp1252. Decoding the raw
-    bytes as cp1252 raises (the bug); the fix's kwargs read it cleanly.
-    """
-    # All-ASCII argv; the child builds the non-ASCII char itself so this is
-    # deterministic regardless of the parent's locale.
+    """Reproduce the bug and fix with a real subprocess: the child emits U+201D
+    (UTF-8 E2 80 9D, byte 0x9D undefined in cp1252) so cp1252 decode raises while
+    the fix's utf-8/replace kwargs read it cleanly."""
+    # All-ASCII argv; the child builds the non-ASCII char so it's locale-independent.
     child = (
         "import sys; "
         "sys.stdout.buffer.write(('tensor ' + chr(0x201D) + ' x\\n').encode('utf-8'))"
@@ -131,8 +108,7 @@ def test_utf8_replace_decodes_non_cp1252_subprocess_output():
     raw = subprocess.run([sys.executable, "-c", child], capture_output = True).stdout
     assert b"\x9d" in raw  # precondition: output carries the cp1252-undefined byte
 
-    # Failing behaviour before the fix: cp1252 (the Windows default) cannot
-    # decode this output.
+    # Before the fix: cp1252 (the Windows default) cannot decode this output.
     with pytest.raises(UnicodeDecodeError):
         raw.decode("cp1252")