Improve version testing (closes #52)

CHANGES.rst

@@ -4,6 +4,7 @@
 - Bundled liberfa version update to v1.7.1.
 - Improved the setup machinery to ensure a proper configuration of the
   embedded liberfa (see also https://github.com/liberfa/erfa/pull/73).
+- Improve version testing (see gh-52).
 
 
 1.7 (2020-05-31)

erfa/tests/test_erfa.py

@@ -19,6 +19,28 @@ def __init__(self, *args, **kwargs):
             pass
 
 
+def embedded_liberfa(path=erfa.ufunc.__file__):
+    import platform
+    import subprocess
+
+    lddcmd = ['ldd']
+    if platform.system() == 'Darwin':
+        lddcmd = ['otool', '-L']
+    elif platform.system() == 'Windows':
+        # lddcmd = ['']  # TODO
+        return None
+
+    lddcmd.append(path)
+    try:
+        out = subprocess.run(lddcmd, check=True,
+                             encoding='utf-8', stdout=subprocess.PIPE)
+                             # capture_output=True, text=True)  # Python 3.7
+    except (subprocess.SubprocessError, OSError):
+        return None
+    else:
+        return 'erfa' not in out.stdout
+
+
 class TestVersion:
     def test_erfa_version(self):
         assert hasattr(erfa.version, 'erfa_version')
@@ -38,9 +60,15 @@ def test_version(self):
         assert hasattr(erfa, '__version__')
         version = erfa.__version__
         assert version is erfa.version.version
+
+    @pytest.mark.skipif(not embedded_liberfa(), reason='system liberfa')
+    def test_version_with_embedded_liberfa(self):
         # Oops, we had the wrong version for quite a while...
-        assert (erfa.version.erfa_version == '1.6.0' and version.startswith('1.7.0')
-                or version.startswith(erfa.version.erfa_version))
+        version = erfa.__version__
+        if erfa.version.erfa_version == '1.6.0':
+            assert version == '1.7.0'
+        else:
+            assert version.startswith(erfa.version.erfa_version)
 
 
 def test_erfa_wrapper():

setup.py

@@ -4,6 +4,9 @@
 import os
 import re
 import sys
+import inspect
+import textwrap
+import functools
 import setuptools
 import subprocess
 from warnings import warn
@@ -131,7 +134,42 @@ def get_extensions():
     return [erfa_ext]
 
 
-VERSION_TEMPLATE = """
+def _guess_next_dev(version, liberfadir=None):
+    from setuptools_scm import git
+    from setuptools_scm.version import guess_next_version
+
+    if liberfadir is None:
+        import pathlib
+        liberfadir = pathlib.Path(__file__).parent.parent / 'liberfa' / 'erfa'
+
+    erfa_version = git.parse(liberfadir)
+    if not erfa_version.exact:
+        warn(f'liberfa/erfa not at a tagged release, but at {erfa_version}')
+
+    erfa_tag = erfa_version.format_with("{tag}")
+    version_string = str(version.tag)
+
+    if version.exact:
+        if not version_string.startswith(erfa_tag):
+            warn(f'tag {version_string} does not start with liberfa/erfa tag {erfa_tag}')
+
+        return version_string
+
+    else:
+        if erfa_tag > version_string:
+            guessed = erfa_tag
+        elif 'dev' in version_string or len(version_string.split('.')) > 3:
+            return guess_next_version(version.tag)
+        else:
+            guessed = version_string.partition("+")[0] + '.1'
+        return version.format_with("{guessed}.dev{distance}", guessed=guessed)
+
+
+code = textwrap.indent(inspect.getsource(_guess_next_dev), '    ')
+escaped_code = code.replace('{', '{{').replace('}', '}}')
+
+
+VERSION_TEMPLATE = f"""
 '''Wrapper, ERFA and SOFA version information.'''
 
 # Set the version numbers a bit indirectly, so that Sphinx can pick up
@@ -147,45 +185,26 @@ def get_extensions():
 
 del ufunc
 
+
 # Note that we need to fall back to the hard-coded version if either
 # setuptools_scm can't be imported or setuptools_scm can't determine the
 # version, so we catch the generic 'Exception'.
 try:
     from setuptools_scm import get_version
-    version = get_version(root='..', relative_to=__file__)
+
+{escaped_code}
+
+    version = get_version(root='..', version_scheme=_guess_next_dev,
+                          relative_to=__file__)
     '''Version of the python wrappers.'''
 except Exception:
-    version = '{version}'
+    version = '{{version}}'
 else:
-    del get_version
+    del get_version, _guess_next_dev
 """.lstrip()
 
 
-def guess_next_dev(version):
-    from setuptools_scm import git
-    from setuptools_scm.version import guess_next_version
-
-    erfa_version = git.parse(LIBERFADIR)
-    if not erfa_version.exact:
-        warn(f'liberfa/erfa not at a tagged release, but at {erfa_version}')
-
-    erfa_tag = erfa_version.format_with("{tag}")
-    version_string = str(version.tag)
-
-    if version.exact:
-        if not version_string.startswith(erfa_tag):
-            warn(f'tag {version_string} does not start with liberfa/erfa tag {erfa_tag}')
-
-        return version_string
-
-    else:
-        if erfa_tag > version_string:
-            guessed = erfa_tag
-        elif 'dev' in version_string or len(version_string.split('.')) > 3:
-            return guess_next_version(version.tag)
-        else:
-            guessed = version_string.partition("+")[0] + '.1'
-        return version.format_with("{guessed}.dev{distance}", guessed=guessed)
+guess_next_dev = functools.partial(_guess_next_dev, liberfadir=LIBERFADIR)
 
 
 use_scm_version = {