fixed version classifier (forever)

setup.py

@@ -1,6 +1,7 @@
 import codecs
 import os
 import re
+from distutils.version import LooseVersion
 
 from setuptools import setup, find_packages
 
@@ -14,7 +15,7 @@ PACKAGES = find_packages(where="src")
 META_PATH = os.path.join("src", NAME, "__init__.py")
 KEYWORDS = ['gcode', 'cnc', 'parser', 'interpreter']
 CLASSIFIERS = [
-    "Development Status :: 2 - Pre-Alpha",  # see src/pygcode/__init__.py
+    "Development Status :: 3 - Alpha",  # see src/pygcode/__init__.py
     "Intended Audience :: Developers",
     "Intended Audience :: Manufacturing",
     "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
@@ -65,13 +66,49 @@ def find_meta(meta):
     raise RuntimeError("Unable to find __{meta}__ string.".format(meta=meta))
 
 
+def assert_version_classifier(version_str):
+    """
+    Verify version consistency:
+    version number must correspond to the correct "Development Status" classifier
+    :raises: ValueError if error found, but ideally this function does nothing
+    """
+    V = lambda v: LooseVersion(v)
+    # cast version
+    version = V(version_str)
+
+    # get "Development  Status" classifier
+    dev_status_list = [x for x in CLASSIFIERS if x.startswith("Development Status ::")]
+    if len(dev_status_list) != 1:
+        raise ValueError("must be 1 'Development Status' in CLASSIFIERS")
+    classifier = dev_status_list.pop()
+
+    version_map = [
+        (V('0.1'), "Development Status :: 2 - Pre-Alpha"),
+        (V('0.2'), "Development Status :: 3 - Alpha"),
+        (V('0.3'), "Development Status :: 4 - Beta"),
+        (V('1.0'), "Development Status :: 5 - Production/Stable"),
+    ]
+
+    for (test_ver, test_classifier) in reversed(sorted(version_map, key=lambda x: x[0])):
+        if version >= test_ver:
+            if classifier == test_classifier:
+                return  # all good, now forget any of this ever happened
+            else:
+                raise ValueError("for version {ver} classifier should be \n'{good}'\nnot\n'{bad}'".format(
+                    ver=str(version), good=test_classifier, bad=classifier
+                ))
+
+
 if __name__ == "__main__":
+    version = find_meta("version")
+    assert_version_classifier(version)
+
     setup(
         name=NAME,
         description=find_meta("description"),
         license=find_meta("license"),
         url=find_meta("url"),
-        version=find_meta("version"),
+        version=version,
         author=find_meta("author"),
         author_email=find_meta("email"),
         maintainer=find_meta("author"),