Extract core metadata logic into dedicated module

5 files changed, 439 insertions, 417 deletions

diff --git a/setuptools/_core_metadata.py b/setuptools/_core_metadata.py
new file mode 100644
index 00000000..750b09b3
--- /dev/null
+++ b/setuptools/_core_metadata.py
@@ -0,0 +1,191 @@
+"""
+Handling of Core Metadata for Python packages (including reading and writing).
+
+See: https://packaging.python.org/en/latest/specifications/core-metadata/
+"""
+import textwrap
+from email import message_from_file
+from email.message import Message
+from typing import Optional, List
+
+from distutils.util import rfc822_escape
+
+from .extern.packaging.version import Version
+from .warnings import SetuptoolsDeprecationWarning
+
+
+def get_metadata_version(self):
+    mv = getattr(self, 'metadata_version', None)
+    if mv is None:
+        mv = Version('2.1')
+        self.metadata_version = mv
+    return mv
+
+
+def rfc822_unescape(content: str) -> str:
+    """Reverse RFC-822 escaping by removing leading whitespaces from content."""
+    lines = content.splitlines()
+    if len(lines) == 1:
+        return lines[0].lstrip()
+    return '\n'.join((lines[0].lstrip(), textwrap.dedent('\n'.join(lines[1:]))))
+
+
+def _read_field_from_msg(msg: Message, field: str) -> Optional[str]:
+    """Read Message header field."""
+    value = msg[field]
+    if value == 'UNKNOWN':
+        return None
+    return value
+
+
+def _read_field_unescaped_from_msg(msg: Message, field: str) -> Optional[str]:
+    """Read Message header field and apply rfc822_unescape."""
+    value = _read_field_from_msg(msg, field)
+    if value is None:
+        return value
+    return rfc822_unescape(value)
+
+
+def _read_list_from_msg(msg: Message, field: str) -> Optional[List[str]]:
+    """Read Message header field and return all results as list."""
+    values = msg.get_all(field, None)
+    if values == []:
+        return None
+    return values
+
+
+def _read_payload_from_msg(msg: Message) -> Optional[str]:
+    value = msg.get_payload().strip()
+    if value == 'UNKNOWN' or not value:
+        return None
+    return value
+
+
+def read_pkg_file(self, file):
+    """Reads the metadata values from a file object."""
+    msg = message_from_file(file)
+
+    self.metadata_version = Version(msg['metadata-version'])
+    self.name = _read_field_from_msg(msg, 'name')
+    self.version = _read_field_from_msg(msg, 'version')
+    self.description = _read_field_from_msg(msg, 'summary')
+    # we are filling author only.
+    self.author = _read_field_from_msg(msg, 'author')
+    self.maintainer = None
+    self.author_email = _read_field_from_msg(msg, 'author-email')
+    self.maintainer_email = None
+    self.url = _read_field_from_msg(msg, 'home-page')
+    self.download_url = _read_field_from_msg(msg, 'download-url')
+    self.license = _read_field_unescaped_from_msg(msg, 'license')
+
+    self.long_description = _read_field_unescaped_from_msg(msg, 'description')
+    if (
+        self.long_description is None and
+        self.metadata_version >= Version('2.1')
+    ):
+        self.long_description = _read_payload_from_msg(msg)
+    self.description = _read_field_from_msg(msg, 'summary')
+
+    if 'keywords' in msg:
+        self.keywords = _read_field_from_msg(msg, 'keywords').split(',')
+
+    self.platforms = _read_list_from_msg(msg, 'platform')
+    self.classifiers = _read_list_from_msg(msg, 'classifier')
+
+    # PEP 314 - these fields only exist in 1.1
+    if self.metadata_version == Version('1.1'):
+        self.requires = _read_list_from_msg(msg, 'requires')
+        self.provides = _read_list_from_msg(msg, 'provides')
+        self.obsoletes = _read_list_from_msg(msg, 'obsoletes')
+    else:
+        self.requires = None
+        self.provides = None
+        self.obsoletes = None
+
+    self.license_files = _read_list_from_msg(msg, 'license-file')
+
+
+def single_line(val):
+    """
+    Quick and dirty validation for Summary pypa/setuptools#1390.
+    """
+    if '\n' in val:
+        # TODO: Replace with `raise ValueError("newlines not allowed")`
+        # after reviewing #2893.
+        msg = "newlines are not allowed in `summary` and will break in the future"
+        SetuptoolsDeprecationWarning.emit("Invalid config.", msg)
+        # due_date is undefined. Controversial change, there was a lot of push back.
+        val = val.strip().split('\n')[0]
+    return val
+
+
+# Based on Python 3.5 version
+def write_pkg_file(self, file):  # noqa: C901  # is too complex (14)  # FIXME
+    """Write the PKG-INFO format data to a file object."""
+    version = self.get_metadata_version()
+
+    def write_field(key, value):
+        file.write("%s: %s\n" % (key, value))
+
+    write_field('Metadata-Version', str(version))
+    write_field('Name', self.get_name())
+    write_field('Version', self.get_version())
+
+    summary = self.get_description()
+    if summary:
+        write_field('Summary', single_line(summary))
+
+    optional_fields = (
+        ('Home-page', 'url'),
+        ('Download-URL', 'download_url'),
+        ('Author', 'author'),
+        ('Author-email', 'author_email'),
+        ('Maintainer', 'maintainer'),
+        ('Maintainer-email', 'maintainer_email'),
+    )
+
+    for field, attr in optional_fields:
+        attr_val = getattr(self, attr, None)
+        if attr_val is not None:
+            write_field(field, attr_val)
+
+    license = self.get_license()
+    if license:
+        write_field('License', rfc822_escape(license))
+
+    for project_url in self.project_urls.items():
+        write_field('Project-URL', '%s, %s' % project_url)
+
+    keywords = ','.join(self.get_keywords())
+    if keywords:
+        write_field('Keywords', keywords)
+
+    platforms = self.get_platforms() or []
+    for platform in platforms:
+        write_field('Platform', platform)
+
+    self._write_list(file, 'Classifier', self.get_classifiers())
+
+    # PEP 314
+    self._write_list(file, 'Requires', self.get_requires())
+    self._write_list(file, 'Provides', self.get_provides())
+    self._write_list(file, 'Obsoletes', self.get_obsoletes())
+
+    # Setuptools specific for PEP 345
+    if hasattr(self, 'python_requires'):
+        write_field('Requires-Python', self.python_requires)
+
+    # PEP 566
+    if self.long_description_content_type:
+        write_field('Description-Content-Type', self.long_description_content_type)
+    if self.provides_extras:
+        for extra in self.provides_extras:
+            write_field('Provides-Extra', extra)
+
+    self._write_list(file, 'License-File', self.license_files or [])
+
+    long_description = self.get_long_description()
+    if long_description:
+        file.write("\n%s" % long_description)
+        if not long_description.endswith("\n"):
+            file.write("\n")
diff --git a/setuptools/dist.py b/setuptools/dist.py
index a24e256e..c5c1bc2c 100644
--- a/setuptools/dist.py
+++ b/setuptools/dist.py
@@ -15,15 +15,11 @@ from distutils.debug import DEBUG
 from distutils.fancy_getopt import translate_longopt
 from glob import iglob
 import itertools
-import textwrap
 from contextlib import suppress
-from typing import List, Optional, Set, TYPE_CHECKING
+from typing import List, Optional, Set
 from pathlib import Path
 
-from email import message_from_file
-
 from distutils.errors import DistutilsOptionError, DistutilsSetupError
-from distutils.util import rfc822_escape
 
 from setuptools.extern import packaging
 from setuptools.extern import ordered_set
@@ -36,15 +32,12 @@ from setuptools.monkey import get_unpatched
 from setuptools.config import setupcfg, pyprojecttoml
 from setuptools.discovery import ConfigDiscovery
 
-from setuptools.extern.packaging import version
 from . import _reqs
 from . import _entry_points
 from . import _normalization
 from ._importlib import metadata
 from .warnings import InformationOnly, SetuptoolsDeprecationWarning
 
-if TYPE_CHECKING:
-    from email.message import Message
 
 __import__('setuptools.extern.packaging.specifiers')
 __import__('setuptools.extern.packaging.version')
@@ -60,183 +53,6 @@ def _get_unpatched(cls):
     return get_unpatched(cls)
 
 
-def get_metadata_version(self):
-    mv = getattr(self, 'metadata_version', None)
-    if mv is None:
-        mv = version.Version('2.1')
-        self.metadata_version = mv
-    return mv
-
-
-def rfc822_unescape(content: str) -> str:
-    """Reverse RFC-822 escaping by removing leading whitespaces from content."""
-    lines = content.splitlines()
-    if len(lines) == 1:
-        return lines[0].lstrip()
-    return '\n'.join((lines[0].lstrip(), textwrap.dedent('\n'.join(lines[1:]))))
-
-
-def _read_field_from_msg(msg: "Message", field: str) -> Optional[str]:
-    """Read Message header field."""
-    value = msg[field]
-    if value == 'UNKNOWN':
-        return None
-    return value
-
-
-def _read_field_unescaped_from_msg(msg: "Message", field: str) -> Optional[str]:
-    """Read Message header field and apply rfc822_unescape."""
-    value = _read_field_from_msg(msg, field)
-    if value is None:
-        return value
-    return rfc822_unescape(value)
-
-
-def _read_list_from_msg(msg: "Message", field: str) -> Optional[List[str]]:
-    """Read Message header field and return all results as list."""
-    values = msg.get_all(field, None)
-    if values == []:
-        return None
-    return values
-
-
-def _read_payload_from_msg(msg: "Message") -> Optional[str]:
-    value = msg.get_payload().strip()
-    if value == 'UNKNOWN' or not value:
-        return None
-    return value
-
-
-def read_pkg_file(self, file):
-    """Reads the metadata values from a file object."""
-    msg = message_from_file(file)
-
-    self.metadata_version = version.Version(msg['metadata-version'])
-    self.name = _read_field_from_msg(msg, 'name')
-    self.version = _read_field_from_msg(msg, 'version')
-    self.description = _read_field_from_msg(msg, 'summary')
-    # we are filling author only.
-    self.author = _read_field_from_msg(msg, 'author')
-    self.maintainer = None
-    self.author_email = _read_field_from_msg(msg, 'author-email')
-    self.maintainer_email = None
-    self.url = _read_field_from_msg(msg, 'home-page')
-    self.download_url = _read_field_from_msg(msg, 'download-url')
-    self.license = _read_field_unescaped_from_msg(msg, 'license')
-
-    self.long_description = _read_field_unescaped_from_msg(msg, 'description')
-    if (
-        self.long_description is None and
-        self.metadata_version >= version.Version('2.1')
-    ):
-        self.long_description = _read_payload_from_msg(msg)
-    self.description = _read_field_from_msg(msg, 'summary')
-
-    if 'keywords' in msg:
-        self.keywords = _read_field_from_msg(msg, 'keywords').split(',')
-
-    self.platforms = _read_list_from_msg(msg, 'platform')
-    self.classifiers = _read_list_from_msg(msg, 'classifier')
-
-    # PEP 314 - these fields only exist in 1.1
-    if self.metadata_version == version.Version('1.1'):
-        self.requires = _read_list_from_msg(msg, 'requires')
-        self.provides = _read_list_from_msg(msg, 'provides')
-        self.obsoletes = _read_list_from_msg(msg, 'obsoletes')
-    else:
-        self.requires = None
-        self.provides = None
-        self.obsoletes = None
-
-    self.license_files = _read_list_from_msg(msg, 'license-file')
-
-
-def single_line(val):
-    """
-    Quick and dirty validation for Summary pypa/setuptools#1390.
-    """
-    if '\n' in val:
-        # TODO: Replace with `raise ValueError("newlines not allowed")`
-        # after reviewing #2893.
-        msg = "newlines are not allowed in `summary` and will break in the future"
-        SetuptoolsDeprecationWarning.emit("Invalid config.", msg)
-        # due_date is undefined. Controversial change, there was a lot of push back.
-        val = val.strip().split('\n')[0]
-    return val
-
-
-# Based on Python 3.5 version
-def write_pkg_file(self, file):  # noqa: C901  # is too complex (14)  # FIXME
-    """Write the PKG-INFO format data to a file object."""
-    version = self.get_metadata_version()
-
-    def write_field(key, value):
-        file.write("%s: %s\n" % (key, value))
-
-    write_field('Metadata-Version', str(version))
-    write_field('Name', self.get_name())
-    write_field('Version', self.get_version())
-
-    summary = self.get_description()
-    if summary:
-        write_field('Summary', single_line(summary))
-
-    optional_fields = (
-        ('Home-page', 'url'),
-        ('Download-URL', 'download_url'),
-        ('Author', 'author'),
-        ('Author-email', 'author_email'),
-        ('Maintainer', 'maintainer'),
-        ('Maintainer-email', 'maintainer_email'),
-    )
-
-    for field, attr in optional_fields:
-        attr_val = getattr(self, attr, None)
-        if attr_val is not None:
-            write_field(field, attr_val)
-
-    license = self.get_license()
-    if license:
-        write_field('License', rfc822_escape(license))
-
-    for project_url in self.project_urls.items():
-        write_field('Project-URL', '%s, %s' % project_url)
-
-    keywords = ','.join(self.get_keywords())
-    if keywords:
-        write_field('Keywords', keywords)
-
-    platforms = self.get_platforms() or []
-    for platform in platforms:
-        write_field('Platform', platform)
-
-    self._write_list(file, 'Classifier', self.get_classifiers())
-
-    # PEP 314
-    self._write_list(file, 'Requires', self.get_requires())
-    self._write_list(file, 'Provides', self.get_provides())
-    self._write_list(file, 'Obsoletes', self.get_obsoletes())
-
-    # Setuptools specific for PEP 345
-    if hasattr(self, 'python_requires'):
-        write_field('Requires-Python', self.python_requires)
-
-    # PEP 566
-    if self.long_description_content_type:
-        write_field('Description-Content-Type', self.long_description_content_type)
-    if self.provides_extras:
-        for extra in self.provides_extras:
-            write_field('Provides-Extra', extra)
-
-    self._write_list(file, 'License-File', self.license_files or [])
-
-    long_description = self.get_long_description()
-    if long_description:
-        file.write("\n%s" % long_description)
-        if not long_description.endswith("\n"):
-            file.write("\n")
-
-
 sequence = tuple, list
 
 
diff --git a/setuptools/monkey.py b/setuptools/monkey.py
index 50653fc7..23a5832d 100644
--- a/setuptools/monkey.py
+++ b/setuptools/monkey.py
@@ -11,6 +11,7 @@ from importlib import import_module
 import inspect
 
 import setuptools
+import setuptools._core_metadata
 
 __all__ = []
 """
@@ -100,7 +101,7 @@ def patch_all():
 def _patch_distribution_metadata():
     """Patch write_pkg_file and read_pkg_file for higher metadata standards"""
     for attr in ('write_pkg_file', 'read_pkg_file', 'get_metadata_version'):
-        new_val = getattr(setuptools.dist, attr)
+        new_val = getattr(setuptools._core_metadata, attr)
         setattr(distutils.dist.DistributionMetadata, attr, new_val)
 
 
diff --git a/setuptools/tests/test_core_metadata.py b/setuptools/tests/test_core_metadata.py
new file mode 100644
index 00000000..19d1af1e
--- /dev/null
+++ b/setuptools/tests/test_core_metadata.py
@@ -0,0 +1,245 @@
+import functools
+import io
+
+import pytest
+
+from setuptools import sic
+from setuptools.dist import Distribution
+from setuptools._core_metadata import rfc822_escape, rfc822_unescape
+
+
+EXAMPLE_BASE_INFO = dict(
+    name="package",
+    version="0.0.1",
+    author="Foo Bar",
+    author_email="foo@bar.net",
+    long_description="Long\ndescription",
+    description="Short description",
+    keywords=["one", "two"],
+)
+
+
+@pytest.mark.parametrize(
+    'content, result',
+    (
+        pytest.param(
+            "Just a single line",
+            None,
+            id="single_line",
+        ),
+        pytest.param(
+            "Multiline\nText\nwithout\nextra indents\n",
+            None,
+            id="multiline",
+        ),
+        pytest.param(
+            "Multiline\n    With\n\nadditional\n  indentation",
+            None,
+            id="multiline_with_indentation",
+        ),
+        pytest.param(
+            "  Leading whitespace",
+            "Leading whitespace",
+            id="remove_leading_whitespace",
+        ),
+        pytest.param(
+            "  Leading whitespace\nIn\n    Multiline comment",
+            "Leading whitespace\nIn\n    Multiline comment",
+            id="remove_leading_whitespace_multiline",
+        ),
+    )
+)
+def test_rfc822_unescape(content, result):
+    assert (result or content) == rfc822_unescape(rfc822_escape(content))
+
+
+def __read_test_cases():
+    base = EXAMPLE_BASE_INFO
+
+    params = functools.partial(dict, base)
+
+    test_cases = [
+        ('Metadata version 1.0', params()),
+        ('Metadata Version 1.0: Short long description', params(
+            long_description='Short long description',
+        )),
+        ('Metadata version 1.1: Classifiers', params(
+            classifiers=[
+                'Programming Language :: Python :: 3',
+                'Programming Language :: Python :: 3.7',
+                'License :: OSI Approved :: MIT License',
+            ],
+        )),
+        ('Metadata version 1.1: Download URL', params(
+            download_url='https://example.com',
+        )),
+        ('Metadata Version 1.2: Requires-Python', params(
+            python_requires='>=3.7',
+        )),
+        pytest.param(
+            'Metadata Version 1.2: Project-Url',
+            params(project_urls=dict(Foo='https://example.bar')),
+            marks=pytest.mark.xfail(
+                reason="Issue #1578: project_urls not read",
+            ),
+        ),
+        ('Metadata Version 2.1: Long Description Content Type', params(
+            long_description_content_type='text/x-rst; charset=UTF-8',
+        )),
+        ('License', params(license='MIT', )),
+        ('License multiline', params(
+            license='This is a long license \nover multiple lines',
+        )),
+        pytest.param(
+            'Metadata Version 2.1: Provides Extra',
+            params(provides_extras=['foo', 'bar']),
+            marks=pytest.mark.xfail(reason="provides_extras not read"),
+        ),
+        ('Missing author', dict(
+            name='foo',
+            version='1.0.0',
+            author_email='snorri@sturluson.name',
+        )),
+        ('Missing author e-mail', dict(
+            name='foo',
+            version='1.0.0',
+            author='Snorri Sturluson',
+        )),
+        ('Missing author and e-mail', dict(
+            name='foo',
+            version='1.0.0',
+        )),
+        ('Bypass normalized version', dict(
+            name='foo',
+            version=sic('1.0.0a'),
+        )),
+    ]
+
+    return test_cases
+
+
+@pytest.mark.parametrize('name,attrs', __read_test_cases())
+def test_read_metadata(name, attrs):
+    dist = Distribution(attrs)
+    metadata_out = dist.metadata
+    dist_class = metadata_out.__class__
+
+    # Write to PKG_INFO and then load into a new metadata object
+    PKG_INFO = io.StringIO()
+
+    metadata_out.write_pkg_file(PKG_INFO)
+
+    PKG_INFO.seek(0)
+    metadata_in = dist_class()
+    metadata_in.read_pkg_file(PKG_INFO)
+
+    tested_attrs = [
+        ('name', dist_class.get_name),
+        ('version', dist_class.get_version),
+        ('author', dist_class.get_contact),
+        ('author_email', dist_class.get_contact_email),
+        ('metadata_version', dist_class.get_metadata_version),
+        ('provides', dist_class.get_provides),
+        ('description', dist_class.get_description),
+        ('long_description', dist_class.get_long_description),
+        ('download_url', dist_class.get_download_url),
+        ('keywords', dist_class.get_keywords),
+        ('platforms', dist_class.get_platforms),
+        ('obsoletes', dist_class.get_obsoletes),
+        ('requires', dist_class.get_requires),
+        ('classifiers', dist_class.get_classifiers),
+        ('project_urls', lambda s: getattr(s, 'project_urls', {})),
+        ('provides_extras', lambda s: getattr(s, 'provides_extras', set())),
+    ]
+
+    for attr, getter in tested_attrs:
+        assert getter(metadata_in) == getter(metadata_out)
+
+
+def __maintainer_test_cases():
+    attrs = {"name": "package",
+             "version": "1.0",
+             "description": "xxx"}
+
+    def merge_dicts(d1, d2):
+        d1 = d1.copy()
+        d1.update(d2)
+
+        return d1
+
+    test_cases = [
+        ('No author, no maintainer', attrs.copy()),
+        ('Author (no e-mail), no maintainer', merge_dicts(
+            attrs,
+            {'author': 'Author Name'})),
+        ('Author (e-mail), no maintainer', merge_dicts(
+            attrs,
+            {'author': 'Author Name',
+             'author_email': 'author@name.com'})),
+        ('No author, maintainer (no e-mail)', merge_dicts(
+            attrs,
+            {'maintainer': 'Maintainer Name'})),
+        ('No author, maintainer (e-mail)', merge_dicts(
+            attrs,
+            {'maintainer': 'Maintainer Name',
+             'maintainer_email': 'maintainer@name.com'})),
+        ('Author (no e-mail), Maintainer (no-email)', merge_dicts(
+            attrs,
+            {'author': 'Author Name',
+             'maintainer': 'Maintainer Name'})),
+        ('Author (e-mail), Maintainer (e-mail)', merge_dicts(
+            attrs,
+            {'author': 'Author Name',
+             'author_email': 'author@name.com',
+             'maintainer': 'Maintainer Name',
+             'maintainer_email': 'maintainer@name.com'})),
+        ('No author (e-mail), no maintainer (e-mail)', merge_dicts(
+            attrs,
+            {'author_email': 'author@name.com',
+             'maintainer_email': 'maintainer@name.com'})),
+        ('Author unicode', merge_dicts(
+            attrs,
+            {'author': '鉄沢寛'})),
+        ('Maintainer unicode', merge_dicts(
+            attrs,
+            {'maintainer': 'Jan Łukasiewicz'})),
+    ]
+
+    return test_cases
+
+
+@pytest.mark.parametrize('name,attrs', __maintainer_test_cases())
+def test_maintainer_author(name, attrs, tmpdir):
+    tested_keys = {
+        'author': 'Author',
+        'author_email': 'Author-email',
+        'maintainer': 'Maintainer',
+        'maintainer_email': 'Maintainer-email',
+    }
+
+    # Generate a PKG-INFO file
+    dist = Distribution(attrs)
+    fn = tmpdir.mkdir('pkg_info')
+    fn_s = str(fn)
+
+    dist.metadata.write_pkg_info(fn_s)
+
+    with io.open(str(fn.join('PKG-INFO')), 'r', encoding='utf-8') as f:
+        raw_pkg_lines = f.readlines()
+
+    # Drop blank lines and strip lines from default description
+    pkg_lines = list(filter(None, raw_pkg_lines[:-2]))
+
+    pkg_lines_set = set(pkg_lines)
+
+    # Duplicate lines should not be generated
+    assert len(pkg_lines) == len(pkg_lines_set)
+
+    for fkey, dkey in tested_keys.items():
+        val = attrs.get(dkey, None)
+        if val is None:
+            for line in pkg_lines:
+                assert not line.startswith(fkey + ':')
+        else:
+            line = '%s: %s' % (fkey, val)
+            assert line in pkg_lines_set
diff --git a/setuptools/tests/test_dist.py b/setuptools/tests/test_dist.py
index e7d2f5ca..b87c3704 100644
--- a/setuptools/tests/test_dist.py
+++ b/setuptools/tests/test_dist.py
@@ -1,7 +1,5 @@
-import io
 import collections
 import re
-import functools
 import os
 import urllib.request
 import urllib.parse
@@ -11,10 +9,7 @@ from setuptools.dist import (
     check_package_data,
     DistDeprecationWarning,
     check_specifier,
-    rfc822_escape,
-    rfc822_unescape,
 )
-from setuptools import sic
 from setuptools import Distribution
 
 from .textwrap import DALS
@@ -82,198 +77,6 @@ EXAMPLE_BASE_INFO = dict(
 )
 
 
-def __read_test_cases():
-    base = EXAMPLE_BASE_INFO
-
-    params = functools.partial(dict, base)
-
-    test_cases = [
-        ('Metadata version 1.0', params()),
-        ('Metadata Version 1.0: Short long description', params(
-            long_description='Short long description',
-        )),
-        ('Metadata version 1.1: Classifiers', params(
-            classifiers=[
-                'Programming Language :: Python :: 3',
-                'Programming Language :: Python :: 3.7',
-                'License :: OSI Approved :: MIT License',
-            ],
-        )),
-        ('Metadata version 1.1: Download URL', params(
-            download_url='https://example.com',
-        )),
-        ('Metadata Version 1.2: Requires-Python', params(
-            python_requires='>=3.7',
-        )),
-        pytest.param(
-            'Metadata Version 1.2: Project-Url',
-            params(project_urls=dict(Foo='https://example.bar')),
-            marks=pytest.mark.xfail(
-                reason="Issue #1578: project_urls not read",
-            ),
-        ),
-        ('Metadata Version 2.1: Long Description Content Type', params(
-            long_description_content_type='text/x-rst; charset=UTF-8',
-        )),
-        ('License', params(license='MIT', )),
-        ('License multiline', params(
-            license='This is a long license \nover multiple lines',
-        )),
-        pytest.param(
-            'Metadata Version 2.1: Provides Extra',
-            params(provides_extras=['foo', 'bar']),
-            marks=pytest.mark.xfail(reason="provides_extras not read"),
-        ),
-        ('Missing author', dict(
-            name='foo',
-            version='1.0.0',
-            author_email='snorri@sturluson.name',
-        )),
-        ('Missing author e-mail', dict(
-            name='foo',
-            version='1.0.0',
-            author='Snorri Sturluson',
-        )),
-        ('Missing author and e-mail', dict(
-            name='foo',
-            version='1.0.0',
-        )),
-        ('Bypass normalized version', dict(
-            name='foo',
-            version=sic('1.0.0a'),
-        )),
-    ]
-
-    return test_cases
-
-
-@pytest.mark.parametrize('name,attrs', __read_test_cases())
-def test_read_metadata(name, attrs):
-    dist = Distribution(attrs)
-    metadata_out = dist.metadata
-    dist_class = metadata_out.__class__
-
-    # Write to PKG_INFO and then load into a new metadata object
-    PKG_INFO = io.StringIO()
-
-    metadata_out.write_pkg_file(PKG_INFO)
-
-    PKG_INFO.seek(0)
-    metadata_in = dist_class()
-    metadata_in.read_pkg_file(PKG_INFO)
-
-    tested_attrs = [
-        ('name', dist_class.get_name),
-        ('version', dist_class.get_version),
-        ('author', dist_class.get_contact),
-        ('author_email', dist_class.get_contact_email),
-        ('metadata_version', dist_class.get_metadata_version),
-        ('provides', dist_class.get_provides),
-        ('description', dist_class.get_description),
-        ('long_description', dist_class.get_long_description),
-        ('download_url', dist_class.get_download_url),
-        ('keywords', dist_class.get_keywords),
-        ('platforms', dist_class.get_platforms),
-        ('obsoletes', dist_class.get_obsoletes),
-        ('requires', dist_class.get_requires),
-        ('classifiers', dist_class.get_classifiers),
-        ('project_urls', lambda s: getattr(s, 'project_urls', {})),
-        ('provides_extras', lambda s: getattr(s, 'provides_extras', set())),
-    ]
-
-    for attr, getter in tested_attrs:
-        assert getter(metadata_in) == getter(metadata_out)
-
-
-def __maintainer_test_cases():
-    attrs = {"name": "package",
-             "version": "1.0",
-             "description": "xxx"}
-
-    def merge_dicts(d1, d2):
-        d1 = d1.copy()
-        d1.update(d2)
-
-        return d1
-
-    test_cases = [
-        ('No author, no maintainer', attrs.copy()),
-        ('Author (no e-mail), no maintainer', merge_dicts(
-            attrs,
-            {'author': 'Author Name'})),
-        ('Author (e-mail), no maintainer', merge_dicts(
-            attrs,
-            {'author': 'Author Name',
-             'author_email': 'author@name.com'})),
-        ('No author, maintainer (no e-mail)', merge_dicts(
-            attrs,
-            {'maintainer': 'Maintainer Name'})),
-        ('No author, maintainer (e-mail)', merge_dicts(
-            attrs,
-            {'maintainer': 'Maintainer Name',
-             'maintainer_email': 'maintainer@name.com'})),
-        ('Author (no e-mail), Maintainer (no-email)', merge_dicts(
-            attrs,
-            {'author': 'Author Name',
-             'maintainer': 'Maintainer Name'})),
-        ('Author (e-mail), Maintainer (e-mail)', merge_dicts(
-            attrs,
-            {'author': 'Author Name',
-             'author_email': 'author@name.com',
-             'maintainer': 'Maintainer Name',
-             'maintainer_email': 'maintainer@name.com'})),
-        ('No author (e-mail), no maintainer (e-mail)', merge_dicts(
-            attrs,
-            {'author_email': 'author@name.com',
-             'maintainer_email': 'maintainer@name.com'})),
-        ('Author unicode', merge_dicts(
-            attrs,
-            {'author': '鉄沢寛'})),
-        ('Maintainer unicode', merge_dicts(
-            attrs,
-            {'maintainer': 'Jan Łukasiewicz'})),
-    ]
-
-    return test_cases
-
-
-@pytest.mark.parametrize('name,attrs', __maintainer_test_cases())
-def test_maintainer_author(name, attrs, tmpdir):
-    tested_keys = {
-        'author': 'Author',
-        'author_email': 'Author-email',
-        'maintainer': 'Maintainer',
-        'maintainer_email': 'Maintainer-email',
-    }
-
-    # Generate a PKG-INFO file
-    dist = Distribution(attrs)
-    fn = tmpdir.mkdir('pkg_info')
-    fn_s = str(fn)
-
-    dist.metadata.write_pkg_info(fn_s)
-
-    with io.open(str(fn.join('PKG-INFO')), 'r', encoding='utf-8') as f:
-        raw_pkg_lines = f.readlines()
-
-    # Drop blank lines and strip lines from default description
-    pkg_lines = list(filter(None, raw_pkg_lines[:-2]))
-
-    pkg_lines_set = set(pkg_lines)
-
-    # Duplicate lines should not be generated
-    assert len(pkg_lines) == len(pkg_lines_set)
-
-    for fkey, dkey in tested_keys.items():
-        val = attrs.get(dkey, None)
-        if val is None:
-            for line in pkg_lines:
-                assert not line.startswith(fkey + ':')
-        else:
-            line = '%s: %s' % (fkey, val)
-            assert line in pkg_lines_set
-
-
 def test_provides_extras_deterministic_order():
     extras = collections.OrderedDict()
     extras['a'] = ['foo']
@@ -347,40 +150,6 @@ def test_check_specifier():
         dist = Distribution(attrs)
 
 
-@pytest.mark.parametrize(
-    'content, result',
-    (
-        pytest.param(
-            "Just a single line",
-            None,
-            id="single_line",
-        ),
-        pytest.param(
-            "Multiline\nText\nwithout\nextra indents\n",
-            None,
-            id="multiline",
-        ),
-        pytest.param(
-            "Multiline\n    With\n\nadditional\n  indentation",
-            None,
-            id="multiline_with_indentation",
-        ),
-        pytest.param(
-            "  Leading whitespace",
-            "Leading whitespace",
-            id="remove_leading_whitespace",
-        ),
-        pytest.param(
-            "  Leading whitespace\nIn\n    Multiline comment",
-            "Leading whitespace\nIn\n    Multiline comment",
-            id="remove_leading_whitespace_multiline",
-        ),
-    )
-)
-def test_rfc822_unescape(content, result):
-    assert (result or content) == rfc822_unescape(rfc822_escape(content))
-
-
 def test_metadata_name():
     with pytest.raises(DistutilsSetupError, match='missing.*name'):
         Distribution()._validate_metadata()