diff --git a/.gitignore b/.gitignore
index dac6e91..2c71ced 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
 /python-editorconfig-0.12.0.tar.gz
+/editorconfig-core-py-0.12.3.tar.gz
+/editorconfig-core-test-e407c1592df0f8e91664835324dea85146f20189.tar.gz
diff --git a/python-editorconfig.spec b/python-editorconfig.spec
index aa9fb7d..af4cfee 100644
--- a/python-editorconfig.spec
+++ b/python-editorconfig.spec
@@ -1,60 +1,121 @@
-%global srcname editorconfig
-%global sum A Python Based distribution of EditorConfig
-
-Name:           python-%{srcname}
-Version:        0.12.0
-Release:        22%{?dist}
-Summary:        %{sum}
-
+# Sphinx-generated HTML documentation is not suitable for packaging; see
+# https://bugzilla.redhat.com/show_bug.cgi?id=2006555 for discussion.
+#
+# We can generate PDF documentation as a substitute.
+%bcond_without doc_pdf
+
+# The tests are stored in a separate repository, which is normally accessed
+# as a git submodule.
+%global tests_commit e407c1592df0f8e91664835324dea85146f20189
+
+Name:           python-editorconfig
+Version:        0.12.3
+Release:        1%{?dist}
+Summary:        EditorConfig File Locator and Interpreter for Python
+
+# See COPYING: the overall license is BSD, but the following files are derived
+# from the Python standard library under the Python license:
+#   - editorconfig/fnmatch.py
+#   - editorconfig/ini.py
 License:        Python and BSD
-URL:            http://editorconfig.org
-Source0:        https://github.com/editorconfig/editorconfig-core-py/archive/v0.12.0.tar.gz#/%{name}-%{version}.tar.gz
+URL:            https://github.com/editorconfig/editorconfig-core-py
+Source0:        %{url}/archive/v%{version}/editorconfig-core-py-%{version}.tar.gz
+%global tests_url https://github.com/editorconfig/editorconfig-core-test
+Source1:        %{tests_url}/archive/%{tests_commit}/editorconfig-core-test-%{tests_commit}.tar.gz
 
 BuildArch:      noarch
-BuildRequires: make
-BuildRequires:  python3-sphinx
+
 BuildRequires:  python3-devel
-BuildRequires:  python3-setuptools
+BuildRequires:  python3dist(setuptools)
 
-%description
-EditorConfig Python Core provides the same functionality as the EditorConfig C
-Core. EditorConfig Python core can be used as a an importable library.
+# For tests:
+BuildRequires:  cmake
 
-%package     -n python3-%{srcname}
-Summary:        %{sum}
-%{?python_provide:%python_provide python3-%{srcname}}
+%if %{with doc_pdf}
+BuildRequires:  make
+BuildRequires:  python3dist(sphinx)
+BuildRequires:  python3-sphinx-latex
+BuildRequires:  latexmk
+%endif
 
-%description -n python3-%{srcname}
+%global common_description %{expand: \
 EditorConfig Python Core provides the same functionality as the EditorConfig C
-Core. EditorConfig Python core can be used as a an importable library.
+Core.}
+
+%description
+%{common_description}
+
+
+%package     -n python3-editorconfig
+Summary:        %{summary}
+
+%description -n python3-editorconfig
+%{common_description}
+
+
+%package        doc
+Summary:        Documentation for python-editorconfig
+
+%description    doc %{common_description}
+
 
 %prep
-%setup -qn %{srcname}-core-py-%{version}
+%setup -q -n editorconfig-core-py-%{version}
+
+rm -vrf tests
+%setup -q -n editorconfig-core-py-%{version} -T -D -b 1
+mv ../editorconfig-core-test-%{tests_commit}/ tests/
 
 
 %build
 %{py3_build}
-cd docs
-make SPHINXBUILD=sphinx-build-3 text
+
+%make_build -C docs text SPHINXOPTS='%{?_smp_mflags}'
+%if %{with doc_pdf}
+%make_build -C docs latex SPHINXOPTS='%{?_smp_mflags}'
+%make_build -C docs/_build/latex LATEXMKOPTS='-quiet'
+%endif
+
+%cmake -DPYTHON_EXECUTABLE='%{python3}'
 
 %install
 %{py3_install}
-mkdir -p $RPM_BUILD_ROOT%{_defaultdocdir}/python3-%{srcname}
-cp docs/_build/text/* $RPM_BUILD_ROOT%{_defaultdocdir}/python3-%{srcname}/
 
+# The command-line tool would conflict with the one from the C version of
+# EditorConfig. It could be installed under a different name, if any one ever
+# reports a need for it.
+rm -vf '%{buildroot}%{_bindir}/editorconfig'
 
-# EditorConfig C already places the official binary into /usr/bin.
-rm $RPM_BUILD_ROOT%{_bindir}/%{srcname}
 
+%check
+export PYTHONPATH='%{buildroot}%{python3_sitelib}'
+%ctest
 
-%files -n python3-%{srcname}
+
+%files -n python3-editorconfig
+%license COPYING LICENSE.BSD LICENSE.PSF
 %doc README.rst
-%license LICENSE.txt
-%{python3_sitelib}/*
-%{_defaultdocdir}/python3-%{srcname}/*
+%{python3_sitelib}/editorconfig
+%{python3_sitelib}/EditorConfig-%{version}-py%{python3_version}.egg-info
+
+
+%files doc
+%license COPYING LICENSE.BSD LICENSE.PSF
+%doc README.rst
+%doc docs/_build/text
+%if %{with doc_pdf}
+%doc docs/_build/latex/EditorConfigPythonCore.pdf
+%endif
 
 
 %changelog
+* Wed Jan 12 2022 Benjamin A. Beasley <code@musicinmybrain.net> - 0.12.3-1
+- Update to 0.12.3 (close RHBZ#1876235)
+- Modernize spec file (still under “old guidelines” for now)
+- Add a -doc subpackage and build PDF
+- Add more license files
+- Run the tests
+
 * Tue Jul 27 2021 Fedora Release Engineering <releng@fedoraproject.org> - 0.12.0-22
 - Second attempt - Rebuilt for
   https://fedoraproject.org/wiki/Fedora_35_Mass_Rebuild
diff --git a/sources b/sources
index 6b86035..d2e7c7d 100644
--- a/sources
+++ b/sources
@@ -1 +1,2 @@
-712a6a3ab23f710f683edb090200c714  python-editorconfig-0.12.0.tar.gz
+SHA512 (editorconfig-core-py-0.12.3.tar.gz) = 005d0698c410c8865d177a1e891b5c51b15255f36303b116fddbbbc08e309d1d60ca3003d27e6fd8455e53c5956db0c29e298f22f4b10950e1f7c56c7c6e0ab3
+SHA512 (editorconfig-core-test-e407c1592df0f8e91664835324dea85146f20189.tar.gz) = cade0e74074d29595f067614da266df551b5b40ef8621c5ceb09b9f4e99cb42413965fdd5459bfe3ed042dfb8df90cb4d32e28ef4ec30264a8a31c2cb1ad5f0d