single opt for get, plus simple unit test

koji/__init__.py

@@ -920,12 +920,25 @@ class RawHeader(object):
         else:
             raise GenericError("Unknown header data type: %x" % dtype)
 
-    def get(self, key, default=None, decode=None):
+    def get(self, key, default=None, decode=None, single=False):
+        # With decode on, we will _mostly_ return the same value that rpmlib will.
+        # There are exceptions where rpmlib will automatically translate or update values, e.g.
+        # * fields that rpm treats as scalars
+        # * special tags like Headerimmutable
+        # * i18n string translations
+        # * the Fileclass extension tag that overlaps a concrete tag
+        # * auto converting PREINPROG/POSTINPROG/etc to string arrays for older rpms
         entry = self.index.get(key)
         if entry is None:
             return default
         else:
-            return self._getitem(*entry[1:], decode=decode)
+            value = self._getitem(*entry[1:], decode=decode)
+            if single and isinstance(value, list):
+                if len(value) == 1:
+                    return value[0]
+                else:
+                    raise ValueError('single value requested for array at key %s' % key)
+            return value
 
 
 def rip_rpm_sighdr(src):

tests/test_lib/test_rawheader_fields.py

@@ -0,0 +1,37 @@
+# coding=utf-8
+from __future__ import absolute_import
+import os.path
+import unittest
+
+import koji
+
+
+class TestRawHeaderFields(unittest.TestCase):
+
+    RPMFILES = [
+        "test-deps-1-1.fc24.x86_64.rpm",
+        "test-files-1-1.fc27.noarch.rpm",
+        "test-nosrc-1-1.fc24.nosrc.rpm",
+        "test-deps-1-1.fc24.x86_64.rpm.signed",
+        "test-nopatch-1-1.fc24.nosrc.rpm",
+        "test-src-1-1.fc24.src.rpm",
+    ]
+
+    def test_header_sizes(self):
+        for basename in self.RPMFILES:
+            fn = os.path.join(os.path.dirname(__file__), 'data/rpms', basename)
+
+            rh = koji.RawHeader(koji.rip_rpm_hdr(fn))
+            hdr = koji.get_rpm_header(fn)
+
+            for key in rh.index:
+                if key in (63, 1141):
+                    continue
+                ours = rh.get(key, decode=True)
+                theirs = hdr[key]
+                if type(ours) != type(theirs):
+                    if isinstance(ours, list) and len(ours) == 1 and ours[0] == theirs:
+                        # rpm is presenting as a scalar
+                        continue
+                # otherwise
+                self.assertEqual(ours, theirs)