Multiple code quality improvements

.flake8

@@ -1,7 +1,14 @@
 [flake8]
+min_python_version = 3.6.0
 max-line-length = 88
 ignore = E501, E203, W503
-per-file-ignores = __init__.py:F401
+per-file-ignores =
+    # N818: error suffix in exception names (API-breaking change)
+    tomlkit/exceptions.py: N818,
+    # FS003: f-string missing prefix
+    tests/test_items.py: FS003,
+    tests/test_api.py: FS003,
+    tests/test_toml_document.py: FS003,
 exclude =
     .git
     __pycache__
@@ -15,3 +22,13 @@ exclude =
     .pytest_cache
     .vscode
     .github
+ban-relative-imports = true
+# flake8-use-fstring: https://github.com/MichaelKim0407/flake8-use-fstring#--percent-greedy-and---format-greedy
+format-greedy = 1
+inline-quotes = double
+eradicate-whitelist-extend = ^-.*;
+extend-ignore =
+    # E203: Whitespace before ':' (pycqa/pycodestyle#373)
+    E203,
+    # SIM106: Handle error-cases first
+    SIM106,

.pre-commit-config.yaml

@@ -1,15 +1,14 @@
 repos:
-  - repo: https://github.com/ambv/black
-    rev: 22.3.0
+  - repo: https://github.com/psf/black
+    rev: 22.6.0
     hooks:
       - id: black
 
-  - repo: https://github.com/timothycrosley/isort
+  - repo: https://github.com/pycqa/isort
     rev: 5.10.1
     hooks:
       - id: isort
-        additional_dependencies: [toml]
-        exclude: ^.*/?setup\.py$
+        exclude: docs/.*
 
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.1.0
@@ -19,3 +18,38 @@ repos:
       - id: end-of-file-fixer
         exclude: ^tests/(toml-test|toml-spec-tests)/.*
       - id: debug-statements
+
+  - repo: https://github.com/asottile/yesqa
+    rev: v1.3.0
+    hooks:
+      - id: yesqa
+        additional_dependencies: &flake8_deps
+          - flake8-broken-line==0.4.0
+          - flake8-bugbear==22.7.1
+          - flake8-comprehensions==3.10.0
+          - flake8-eradicate==1.2.1
+          - flake8-quotes==3.3.1
+          - flake8-simplify==0.19.2
+          - flake8-tidy-imports==4.8.0
+          - flake8-typing-imports==1.12.0
+          - flake8-use-fstring==1.3
+          - pep8-naming==0.13.0
+        exclude: ^tomlkit/items\.py
+
+  - repo: https://github.com/asottile/pyupgrade
+    rev: v2.37.1
+    hooks:
+      - id: pyupgrade
+        args: [--py36-plus]
+
+  - repo: https://github.com/hadialqattan/pycln
+    rev: v2.0.1
+    hooks:
+      - id: pycln
+        args: [--all]
+
+  - repo: https://github.com/pycqa/flake8
+    rev: 4.0.1
+    hooks:
+      - id: flake8
+        additional_dependencies: *flake8_deps

tests/test_items.py

@@ -8,6 +8,8 @@
 
 import pytest
 
+from tests.util import assert_is_ppo
+from tests.util import elementary_test
 from tomlkit import api
 from tomlkit import parse
 from tomlkit.exceptions import NonExistentKey
@@ -27,9 +29,6 @@
 from tomlkit.items import item
 from tomlkit.parser import Parser
 
-from .util import assert_is_ppo
-from .util import elementary_test
-
 
 @pytest.fixture()
 def tz_pst():
@@ -120,7 +119,7 @@ def test_aot_unwrap():
     d = item([{"a": "A"}, {"b": "B"}])
     unwrapped = d.unwrap()
     assert_is_ppo(unwrapped, list)
-    for du, dw in zip(unwrapped, d):
+    for du, _ in zip(unwrapped, d):
         assert_is_ppo(du, dict)
         for ku in du:
             vu = du[ku]
@@ -182,26 +181,26 @@ def test_items_can_be_appended_to_and_removed_from_a_table():
     _, table = parser._parse_table()
 
     assert isinstance(table, Table)
-    assert "" == table.as_string()
+    assert table.as_string() == ""
 
     table.append(Key("foo"), String(StringType.SLB, "bar", "bar", Trivia(trail="\n")))
 
-    assert 'foo = "bar"\n' == table.as_string()
+    assert table.as_string() == 'foo = "bar"\n'
 
     table.append(
         Key("baz"),
         Integer(34, Trivia(comment_ws="   ", comment="# Integer", trail=""), "34"),
     )
 
-    assert 'foo = "bar"\nbaz = 34   # Integer' == table.as_string()
+    assert table.as_string() == 'foo = "bar"\nbaz = 34   # Integer'
 
     table.remove(Key("baz"))
 
-    assert 'foo = "bar"\n' == table.as_string()
+    assert table.as_string() == 'foo = "bar"\n'
 
     table.remove(Key("foo"))
 
-    assert "" == table.as_string()
+    assert table.as_string() == ""
 
     with pytest.raises(NonExistentKey):
         table.remove(Key("foo"))
@@ -215,23 +214,23 @@ def test_items_can_be_appended_to_and_removed_from_an_inline_table():
     _, table = parser._parse_item()
 
     assert isinstance(table, InlineTable)
-    assert "{}" == table.as_string()
+    assert table.as_string() == "{}"
 
     table.append(Key("foo"), String(StringType.SLB, "bar", "bar", Trivia(trail="")))
 
-    assert '{foo = "bar"}' == table.as_string()
+    assert table.as_string() == '{foo = "bar"}'
 
     table.append(Key("baz"), Integer(34, Trivia(trail=""), "34"))
 
-    assert '{foo = "bar", baz = 34}' == table.as_string()
+    assert table.as_string() == '{foo = "bar", baz = 34}'
 
     table.remove(Key("baz"))
 
-    assert '{foo = "bar"}' == table.as_string()
+    assert table.as_string() == '{foo = "bar"}'
 
     table.remove(Key("foo"))
 
-    assert "{}" == table.as_string()
+    assert table.as_string() == "{}"
 
     with pytest.raises(NonExistentKey):
         table.remove(Key("foo"))
@@ -339,7 +338,7 @@ def test_array_multiline():
     t = item([])
     t.multiline(True)
 
-    assert "[]" == t.as_string()
+    assert t.as_string() == "[]"
 
 
 def test_array_multiline_modify():
@@ -791,19 +790,19 @@ def test_trim_comments_when_building_inline_table():
     value.comment("Another comment")
     table.append("baz", value)
     assert "# Another comment" not in table.as_string()
-    assert '{foo = "bar", baz = "foobaz"}' == table.as_string()
+    assert table.as_string() == '{foo = "bar", baz = "foobaz"}'
 
 
 def test_deleting_inline_table_elemeent_does_not_leave_trailing_separator():
     table = api.inline_table()
     table["foo"] = "bar"
     table["baz"] = "boom"
 
-    assert '{foo = "bar", baz = "boom"}' == table.as_string()
+    assert table.as_string() == '{foo = "bar", baz = "boom"}'
 
     del table["baz"]
 
-    assert '{foo = "bar"}' == table.as_string()
+    assert table.as_string() == '{foo = "bar"}'
 
     table = api.inline_table()
     table["foo"] = "bar"
@@ -812,7 +811,7 @@ def test_deleting_inline_table_elemeent_does_not_leave_trailing_separator():
 
     table["baz"] = "boom"
 
-    assert '{baz = "boom"}' == table.as_string()
+    assert table.as_string() == '{baz = "boom"}'
 
 
 def test_booleans_comparison():

tests/test_toml_document.py

@@ -9,14 +9,13 @@
 
 import tomlkit
 
+from tests.util import assert_is_ppo
 from tomlkit import parse
 from tomlkit import ws
 from tomlkit._utils import _utc
 from tomlkit.api import document
 from tomlkit.exceptions import NonExistentKey
 
-from .util import assert_is_ppo
-
 
 def test_document_is_a_dict(example):
     content = example("example")
@@ -461,7 +460,8 @@ def test_getting_inline_table_is_still_an_inline_table():
     dev_dependencies["baz"]["source"] = "other"
 
     assert (
-        """\
+        doc.as_string()
+        == """\
 [tool.poetry]
 name = "foo"
 
@@ -472,7 +472,6 @@ def test_getting_inline_table_is_still_an_inline_table():
 [tool.poetry.dev-dependencies]
 baz = {version = "^4.0", source = "other"}
 """
-        == doc.as_string()
     )
 
 
@@ -508,7 +507,7 @@ def test_values_can_still_be_set_for_out_of_order_tables():
     doc = parse(content)
     doc["a"]["a"]["key"] = "new_value"
 
-    assert "new_value" == doc["a"]["a"]["key"]
+    assert doc["a"]["a"]["key"] == "new_value"
 
     expected = """
 [a.a]
@@ -588,18 +587,18 @@ def test_out_of_order_tables_are_still_dicts():
     table = doc["a"]["a"]
     assert "key" in table
     assert "c" in table
-    assert "value" == table.get("key")
+    assert table.get("key") == "value"
     assert {} == table.get("c")
     assert table.get("d") is None
-    assert "foo" == table.get("d", "foo")
+    assert table.get("d", "foo") == "foo"
 
-    assert "bar" == table.setdefault("d", "bar")
-    assert "bar" == table["d"]
+    assert table.setdefault("d", "bar") == "bar"
+    assert table["d"] == "bar"
 
-    assert "value" == table.pop("key")
+    assert table.pop("key") == "value"
     assert "key" not in table
 
-    assert "baz" == table.pop("missing", default="baz")
+    assert table.pop("missing", default="baz") == "baz"
 
     with pytest.raises(KeyError):
         table.pop("missing")
@@ -629,7 +628,7 @@ def test_string_output_order_is_preserved_for_out_of_order_tables():
     constraint["version"] = "^1.0"
     doc["tool"]["poetry"]["dependencies"]["bar"] = constraint
 
-    assert "^1.0" == doc["tool"]["poetry"]["dependencies"]["bar"]["version"]
+    assert doc["tool"]["poetry"]["dependencies"]["bar"]["version"] == "^1.0"
 
     expected = """
 [tool.poetry]

tests/test_toml_spec_tests.py

@@ -78,7 +78,7 @@ def untag(value):
         elif value["type"] == "array":
             return [untag(i) for i in value["value"]]
         else:
-            raise Exception("Unsupported type {}".format(value["type"]))
+            raise Exception(f'Unsupported type {value["type"]}')
     else:
         return {k: untag(v) for k, v in value.items()}
 
@@ -107,6 +107,5 @@ def test_valid_decode(test):
 @pytest.mark.parametrize("test", ERROR_TESTS)
 def test_invalid_decode(test):
     toml_file = os.path.join(SPEC_TEST_DIR, "errors", test + ".toml")
-    with pytest.raises(TOMLKitError):
-        with open(toml_file, encoding="utf-8") as f:
-            parse(f.read())
+    with pytest.raises(TOMLKitError), open(toml_file, encoding="utf-8") as f:
+        parse(f.read())

tests/test_toml_tests.py

@@ -38,7 +38,7 @@ def untag(value):
         elif value["type"] == "array":
             return [untag(i) for i in value["value"]]
         else:
-            raise Exception("Unsupported type {}".format(value["type"]))
+            raise Exception(f'Unsupported type {value["type"]}')
     else:
         return {k: untag(v) for k, v in value.items()}
 
@@ -57,6 +57,7 @@ def test_invalid_decode(invalid_decode_case):
 
 
 def test_invalid_encode(invalid_encode_case):
-    with pytest.raises((TOMLKitError, UnicodeDecodeError)):
-        with open(invalid_encode_case, encoding="utf-8") as f:
-            load(f)
+    with pytest.raises((TOMLKitError, UnicodeDecodeError)), open(
+        invalid_encode_case, encoding="utf-8"
+    ) as f:
+        load(f)

tests/util.py

@@ -43,15 +43,15 @@
 
 
 def assert_not_tomlkit_type(v):
-    for i, T in enumerate(TOMLKIT_TYPES):
-        assert not isinstance(v, T)
+    for _, tomlkit_type in enumerate(TOMLKIT_TYPES):
+        assert not isinstance(v, tomlkit_type)
 
 
-def assert_is_ppo(v_unwrapped, unwrappedType):
+def assert_is_ppo(v_unwrapped, unwrapped_type):
     assert_not_tomlkit_type(v_unwrapped)
-    assert isinstance(v_unwrapped, unwrappedType)
+    assert isinstance(v_unwrapped, unwrapped_type)
 
 
-def elementary_test(v, unwrappedType):
+def elementary_test(v, unwrapped_type):
     v_unwrapped = v.unwrap()
-    assert_is_ppo(v_unwrapped, unwrappedType)
+    assert_is_ppo(v_unwrapped, unwrapped_type)