Adiciona teste que verifica sub-article sem atributo xml:lang

tests/sps/validation/test_article_and_subarticles.py

@@ -126,6 +126,30 @@ def test_article_and_subarticles_with_two_valid_languages_and_one_invalid(self):
             [e.line for e in errors]
         )
 
+    def test_article_and_subarticles_with_one_valid_language_one_empty_and_one_invalid(self):
+        xml_str = """
+        <article article-type="research-article" dtd-version="1.1" specific-use="sps-1.9" xml:lang="en" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">
+            <sub-article article-type="translation" id="s1">
+            </sub-article>
+            <sub-article article-type="translation" id="s2" xml:lang="">
+            </sub-article>
+        </article>
+        """
+        xml_tree = get_xml_tree(xml_str)
+        result, errors = validate_language(xml_tree)
+
+        self.assertFalse(result)
+
+        self.assertListEqual(
+            ['XML translation has no language.', 'XML translation has an invalid language: '],
+            [e.message for e in errors]
+        )
+
+        self.assertListEqual(
+            [3, 5],
+            [e.line for e in errors]
+        )
+
 
     def test_article_and_subarticles_with_two_invalid_languages(self):
         xml_str = """