test_etree: start adding some unit tests to etree module

Lib/ufoLib/test/test_etree.py

@@ -0,0 +1,40 @@
+# coding: utf-8
+from __future__ import absolute_import, unicode_literals
+from ufoLib import etree
+import io
+import pytest
+
+
+@pytest.mark.parametrize(
+    "xml",
+    [
+        (
+            "<root>"
+            '<element key="value">text</element>'
+            "<element>text</element>tail"
+            "<empty-element/>"
+            "</root>"
+        ),
+        (
+            "<root>\n"
+            '  <element key="value">text</element>\n'
+            "  <element>text</element>tail\n"
+            "  <empty-element/>\n"
+            "</root>"
+        ),
+        (
+            '<axis default="400" maximum="1000" minimum="1" name="weight" tag="wght">'
+            '<labelname xml:lang="fa-IR">قطر</labelname>'
+            '</axis>'
+        )
+    ],
+    ids=[
+        "simple_xml_no_indent",
+        "simple_xml_indent",
+        "xml_ns_attrib_utf_8",
+    ]
+)
+def test_roundtrip_string(xml):
+    root = etree.fromstring(xml.encode("utf-8"))
+    result = etree.tostring(root, encoding="utf-8").decode("utf-8")
+    assert result == xml