Fix failed tests

2 files changed, 10 insertions, 6 deletions

diff --git a/prettytable/prettytable.py b/prettytable/prettytable.py
index bb6e16f..3b9bf27 100644
--- a/prettytable/prettytable.py
+++ b/prettytable/prettytable.py
@@ -472,14 +472,18 @@ class PrettyTable(object):
         Arguments:
 
         min_width - minimum width integer"""
+        if self.header:
+            fields = self._field_names
+        else:
+            fields = self._rows[0] if self._rows else []
         result = {
             # minimum column width can't be lesser
             # than header's length
             name: max(
-                len(name),
+                _str_block_width(unicode_(name)),
                 self._min_width.get(name, 0)
             )
-            for name in self._field_names
+            for name in fields
         }
         return result
 
diff --git a/tests/test_prettytable.py b/tests/test_prettytable.py
index f28cfcd..8d353a7 100644
--- a/tests/test_prettytable.py
+++ b/tests/test_prettytable.py
@@ -697,22 +697,22 @@ class UnpaddedTableTest(unittest.TestCase):
     def testUnbordered(self):
         self.x.border = False
         result = self.x.get_string()
-        assert result.strip() == """
+        self.assertEqual(result.strip(), """
 abc
 def
 g..
-""".strip()
+""".strip())
 
     def testBordered(self):
         self.x.border = True
         result = self.x.get_string()
-        assert result.strip() == """
+        self.assertEqual(result.strip(), """
 +-+-+-+
 |a|b|c|
 |d|e|f|
 |g|.|.|
 +-+-+-+
-""".strip()
+""".strip())
 
 
 if __name__ == "__main__":