From 5e53d334e6feea828871ad2113ca52da2e99a5ff Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 21 Jun 2016 10:30:06 +0530
Subject: [PATCH] Add a test for ensure_prefix

---
 src/calibre/ebooks/metadata/opf3.py      | 6 +++---
 src/calibre/ebooks/metadata/opf3_test.py | 6 +++++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/calibre/ebooks/metadata/opf3.py b/src/calibre/ebooks/metadata/opf3.py
index 6339ba32f4..ff48a14138 100644
--- a/src/calibre/ebooks/metadata/opf3.py
+++ b/src/calibre/ebooks/metadata/opf3.py
@@ -133,8 +133,8 @@ def read_prefixes(root):
 def expand_prefix(raw, prefixes):
     return regex(r'(\S+)\s*:\s*(\S+)').sub(lambda m:(prefixes.get(m.group(1), m.group(1)) + ':' + m.group(2)), raw)
 
-def ensure_prefix(root, prefixes, prefix, value):
-    prefixes[prefix] = value
+def ensure_prefix(root, prefixes, prefix, value=None):
+    prefixes[prefix] = value or reserved_prefixes[prefix]
     prefixes = {k:v for k, v in prefixes.iteritems() if reserved_prefixes.get(k) != v}
     if prefixes:
         root.set('prefix', ' '.join('%s: %s' % (k, v) for k, v in prefixes.iteritems()))
@@ -380,7 +380,7 @@ def read_authors(root, prefixes, refines):
     return uniq(roled_authors or unroled_authors)
 
 def set_authors(root, prefixes, refines, authors):
-    ensure_prefix(root, prefixes, 'marc', reserved_prefixes['marc'])
+    ensure_prefix(root, prefixes, 'marc')
     for item in XPath('./opf:metadata/dc:creator')(root):
         props = properties_for_id_with_scheme(item.get('id'), prefixes, refines)
         role = props.get('role')
diff --git a/src/calibre/ebooks/metadata/opf3_test.py b/src/calibre/ebooks/metadata/opf3_test.py
index 2db9b7fca6..771174cd94 100644
--- a/src/calibre/ebooks/metadata/opf3_test.py
+++ b/src/calibre/ebooks/metadata/opf3_test.py
@@ -13,7 +13,7 @@ from calibre.ebooks.metadata.opf3 import (
     parse_prefixes, reserved_prefixes, expand_prefix, read_identifiers,
     read_metadata, set_identifiers, XPath, set_application_id, read_title,
     read_refines, set_title, read_title_sort, read_languages, set_languages,
-    read_authors, Author, set_authors
+    read_authors, Author, set_authors, ensure_prefix, read_prefixes
 )
 
 TEMPLATE = '''<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid"><metadata xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:opf="http://www.idpf.org/2007/opf">{metadata}</metadata></package>'''  # noqa
@@ -35,6 +35,10 @@ class TestOPF3(unittest.TestCase):
                 ('xxx', 'xxx'),
         ):
             self.ae(expand_prefix(raw, reserved_prefixes), expanded)
+        root = self.get_opf()
+        ensure_prefix(root, read_prefixes(root), 'calibre', 'https://calibre-ebook.com')
+        ensure_prefix(root, read_prefixes(root), 'marc', reserved_prefixes['marc'])
+        self.ae(parse_prefixes(root.get('prefix')), {'calibre': 'https://calibre-ebook.com'})
     # }}}
 
     def test_identifiers(self):  # {{{