Show preview changes for tests with options (#9223)

crates/ruff_python_formatter/tests/fixtures.rs

@@ -157,6 +157,39 @@ fn format() {
                     CodeFrame::new("python", &formatted_code)
                 )
                 .unwrap();
+
+                if options.preview().is_enabled() {
+                    continue;
+                }
+
+                // We want to capture the differences in the preview style in our fixtures
+                let options_preview = options.with_preview(PreviewMode::Enabled);
+                let printed_preview = format_module_source(&content, options_preview.clone())
+                    .expect("Formatting to succeed");
+                let formatted_preview = printed_preview.as_code();
+
+                ensure_unchanged_ast(&content, formatted_preview, &options_preview, input_path);
+                ensure_stability_when_formatting_twice(
+                    formatted_preview,
+                    &options_preview,
+                    input_path,
+                );
+
+                if formatted_code != formatted_preview {
+                    // Having both snapshots makes it hard to see the difference, so we're keeping only
+                    // diff.
+                    writeln!(
+                        snapshot,
+                        "#### Preview changes\n{}",
+                        CodeFrame::new(
+                            "diff",
+                            TextDiff::from_lines(formatted_code, formatted_preview)
+                                .unified_diff()
+                                .header("Stable", "Preview")
+                        )
+                    )
+                    .unwrap();
+                }
             }
         } else {
             // We want to capture the differences in the preview style in our fixtures

crates/ruff_python_formatter/tests/snapshots/format@docstring_code_examples_dynamic_line_width.py.snap

@@ -535,6 +535,28 @@ def doctest_extra_indent3():
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -270,9 +270,11 @@
+ 
+         Examples
+         --------
+-        >>> df = pl.DataFrame(
+-        ...     {"foo": [1, 2, 3], "bar": [6, 7, 8], "ham": ["a", "b", "c"]}
+-        ... )
++        >>> df = pl.DataFrame({
++        ...     "foo": [1, 2, 3],
++        ...     "bar": [6, 7, 8],
++        ...     "ham": ["a", "b", "c"],
++        ... })
+         """
+ 
+ 
+```
+
+
 ### Output 2
 ```
 indent-style               = space
@@ -1139,6 +1161,28 @@ def doctest_extra_indent3():
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -270,9 +270,11 @@
+ 
+ 		Examples
+ 		--------
+-		>>> df = pl.DataFrame(
+-		...     {"foo": [1, 2, 3], "bar": [6, 7, 8], "ham": ["a", "b", "c"]}
+-		... )
++		>>> df = pl.DataFrame({
++		...     "foo": [1, 2, 3],
++		...     "bar": [6, 7, 8],
++		...     "ham": ["a", "b", "c"],
++		... })
+ 		"""
+ 
+ 
+```
+
+
 ### Output 4
 ```
 indent-style               = tab
@@ -1876,4 +1920,26 @@ def doctest_extra_indent3():
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -700,9 +700,11 @@
+ 
+ 		Examples
+ 		--------
+-		>>> df = pl.DataFrame(
+-		...         {"foo": [1, 2, 3], "bar": [6, 7, 8], "ham": ["a", "b", "c"]}
+-		... )
++		>>> df = pl.DataFrame({
++		...         "foo": [1, 2, 3],
++		...         "bar": [6, 7, 8],
++		...         "ham": ["a", "b", "c"],
++		... })
+ 		"""
+ 
+ 
+```
+
+
 

crates/ruff_python_formatter/tests/snapshots/format@expression__string.py.snap

@@ -319,6 +319,19 @@ trailing_preferred_quote_texts = [''' "''', ''' ""''', ''' """''', ''' """"''']
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -1,4 +1,5 @@
+ "' test"
++
+ '" test'
+ 
+ '" test'
+```
+
+
 ### Output 2
 ```
 indent-style               = space
@@ -496,4 +509,17 @@ trailing_preferred_quote_texts = [''' "''', ''' ""''', ''' """''', ''' """"''']
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -1,4 +1,5 @@
+ "' test"
++
+ '" test'
+ 
+ '" test'
+```
+
+
 

crates/ruff_python_formatter/tests/snapshots/format@preview.py.snap

@@ -156,6 +156,78 @@ def f():
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -1,13 +1,13 @@
+ """
+ Black's `Preview.module_docstring_newlines`
+ """
++
+ first_stmt_after_module_level_docstring = 1
+ 
+ 
+ class CachedRepository:
+     # Black's `Preview.dummy_implementations`
+-    def get_release_info(self):
+-        ...
++    def get_release_info(self): ...
+ 
+ 
+ def raw_docstring():
+@@ -27,23 +27,22 @@
+ 
+ 
+ class RemoveNewlineBeforeClassDocstring:
+-
+     """Black's `Preview.no_blank_line_before_class_docstring`"""
+ 
+ 
+ def f():
+     """Black's `Preview.prefer_splitting_right_hand_side_of_assignments`"""
+-    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[
+-        bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+-    ] = cccccccc.ccccccccccccc.cccccccc
++    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb] = (
++        cccccccc.ccccccccccccc.cccccccc
++    )
+ 
+-    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[
+-        bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+-    ] = cccccccc.ccccccccccccc().cccccccc
++    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb] = (
++        cccccccc.ccccccccccccc().cccccccc
++    )
+ 
+-    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[
+-        bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+-    ] = cccccccc.ccccccccccccc(d).cccccccc
++    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb] = (
++        cccccccc.ccccccccccccc(d).cccccccc
++    )
+ 
+     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa[bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb] = (
+         cccccccc.ccccccccccccc(d).cccccccc + e
+@@ -57,9 +56,9 @@
+         + eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
+     )
+ 
+-    self._cache: dict[
+-        DependencyCacheKey, list[list[DependencyPackage]]
+-    ] = collections.defaultdict(list)
+-    self._cached_dependencies_by_level: dict[
+-        int, list[DependencyCacheKey]
+-    ] = collections.defaultdict(list)
++    self._cache: dict[DependencyCacheKey, list[list[DependencyPackage]]] = (
++        collections.defaultdict(list)
++    )
++    self._cached_dependencies_by_level: dict[int, list[DependencyCacheKey]] = (
++        collections.defaultdict(list)
++    )
+```
+
+
 ### Output 2
 ```
 indent-style               = space

crates/ruff_python_formatter/tests/snapshots/format@quote_style.py.snap

@@ -129,6 +129,19 @@ def docstring_single():
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -1,4 +1,5 @@
+ 'single'
++
+ 'double'
+ r'r single'
+ r'r double'
+```
+
+
 ### Output 2
 ```
 indent-style               = space
@@ -201,6 +214,19 @@ def docstring_single():
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -1,4 +1,5 @@
+ "single"
++
+ "double"
+ r"r single"
+ r"r double"
+```
+
+
 ### Output 3
 ```
 indent-style               = space
@@ -273,4 +299,17 @@ def docstring_single():
 ```
 
 
+#### Preview changes
+```diff
+--- Stable
++++ Preview
+@@ -1,4 +1,5 @@
+ 'single'
++
+ "double"
+ r'r single'
+ r"r double"
+```
+
+