XMP Text to string conversion + unit tests.

2 files changed, 32 insertions, 9 deletions

diff --git a/src/pyexiv2.py b/src/pyexiv2.py
index a147340..8fa4a48 100644
--- a/src/pyexiv2.py
+++ b/src/pyexiv2.py
@@ -643,16 +643,30 @@ class XmpTag(MetadataTag):
     def _convert_to_string(value, xtype):
         """
         Convert a value to its corresponding string representation.
-        Fallback to str(value) if no standard-compliant conversion can be done.
+
+        @param value: the value to be converted
+        @type value:  depends on xtype (DOCME)
+        @param xtype: the XMP type of the value
+        @type xtype:  C{str}
+
+        @return: the value converted to its corresponding string representation
+        @rtype:  C{str}
+
+        @raise L{XmpValueError}: if the conversion fails
         """
-        if xtype == 'Boolean':
-            if value == True:
-                return 'True'
-            elif value == False:
-                return 'False'
+        if xtype == 'Boolean' and type(value) is bool:
+            return str(value)
+
+        elif xtype == 'Text':
+            if type(value) is unicode:
+                try:
+                    return value.encode('utf-8')
+                except UnicodeEncodeError:
+                    raise XmpValueError(value, xtype)
+            elif type(value) is str:
+                return value
 
-        # Default fallback conversion
-        return str(value)
+        raise XmpValueError(value, xtype)
 
     def __str__(self):
         """
diff --git a/unittest/xmp.py b/unittest/xmp.py
index 8aaa523..d8293fa 100644
--- a/unittest/xmp.py
+++ b/unittest/xmp.py
@@ -52,7 +52,7 @@ class TestXmpTag(unittest.TestCase):
         self.assertEqual(XmpTag._convert_to_string(True, xtype), 'True')
         self.assertEqual(XmpTag._convert_to_string(False, xtype), 'False')
         # Invalid values
-        self.assertEqual(XmpTag._convert_to_string('invalid', xtype), 'invalid')
+        self.failUnlessRaises(XmpValueError, XmpTag._convert_to_string, 'invalid', xtype)
 
     def test_convert_to_python_choice(self):
         pass
@@ -161,6 +161,15 @@ class TestXmpTag(unittest.TestCase):
         self.assertEqual(XmpTag._convert_to_python('Some text with exotic chàräctérʐ.', xtype),
                          u'Some text with exotic chàräctérʐ.')
 
+    def test_convert_to_string_text(self):
+        xtype = 'Text'
+        # Valid values
+        self.assertEqual(XmpTag._convert_to_string(u'Some text', xtype), 'Some text')
+        self.assertEqual(XmpTag._convert_to_string(u'Some text with exotic chàräctérʐ.', xtype),
+                         'Some text with exotic chàräctérʐ.')
+        self.assertEqual(XmpTag._convert_to_string('Some text with exotic chàräctérʐ.', xtype),
+                         'Some text with exotic chàräctérʐ.')
+
     def test_convert_to_python_uri(self):
         xtype = 'URI'
         # Valid values