Implement expand=True for dict views

Author: hugovk

Lib/pprint.py

@@ -321,19 +321,21 @@ def _pprint_dict_view(self, object, stream, indent, allowance, context, level):
             key = _safe_tuple
         else:
             key = _safe_key
+
         write = stream.write
-        write(object.__class__.__name__ + '([')
-        if self._indent_per_level > 1:
-            write((self._indent_per_level - 1) * ' ')
-        length = len(object)
-        if length:
+        write(
+            self._format_block_start(object.__class__.__name__ + "([", indent)
+        )
+
+        if len(object):
             if self._sort_dicts:
                 entries = sorted(object, key=key)
             else:
                 entries = object
-            self._format_items(entries, stream, indent, allowance + 1,
-                               context, level)
-        write('])')
+            self._format_items(
+                entries, stream, indent, allowance + 2, context, level
+            )
+        write(self._format_block_end("])", indent))
 
     def _pprint_mapping_abc_view(self, object, stream, indent, allowance, context, level):
         """Pretty print mapping views from collections.abc."""

Lib/test/test_pprint.py

@@ -1903,6 +1903,49 @@ def __init__(self, *args, **kwargs):
 ]""")
 
 
+    def test_expand_dict_keys(self):
+        d = {"foo": 1, "bar": 2, "baz": 3, "qux": 4, "quux": 5}
+        self.assertEqual(
+            pprint.pformat(d.keys(), width=20, indent=4, expand=True),
+            """\
+dict_keys([
+    'bar',
+    'baz',
+    'foo',
+    'quux',
+    'qux'
+])""",
+        )
+
+    def test_expand_dict_values(self):
+        d = {"foo": 1, "bar": 2, "baz": 3, "qux": 4, "quux": 5}
+        self.assertEqual(
+            pprint.pformat(d.values(), width=20, indent=4, expand=True),
+            """\
+dict_values([
+    1,
+    2,
+    3,
+    4,
+    5
+])""",
+        )
+
+    def test_expand_dict_items(self):
+        d = {"foo": 1, "bar": 2, "baz": 3, "qux": 4, "quux": 5}
+        self.assertEqual(
+            pprint.pformat(d.items(), width=20, indent=4, expand=True),
+            """\
+dict_items([
+    ('bar', 2),
+    ('baz', 3),
+    ('foo', 1),
+    ('quux', 5),
+    ('qux', 4)
+])""",
+        )
+
+
 class DottedPrettyPrinter(pprint.PrettyPrinter):
 
     def format(self, object, context, maxlevels, level):