diff --git a/tests/test_blob.py b/tests/test_blob.py
index 89b666c..b4df272 100644
--- a/tests/test_blob.py
+++ b/tests/test_blob.py
@@ -9,6 +9,8 @@ def test_blob_data_constructor(pEp):
     bdata = b'this is binary \x00\x01\xbb\xa7\xa4\xab test data'
     b = pEp.Blob(bdata)
     assert b.data == bdata
+    assert not b.mime_type
+    assert not b.filename
 
 
 def test_blob_data_property(pEp):
@@ -16,3 +18,14 @@ def test_blob_data_property(pEp):
     b = pEp.Blob(b'dummy')
     b.data = bdata
     assert b.data == bdata
+    assert not b.mime_type
+    assert not b.filename
+
+
+def test_blob_data_property_keeps_other_fields(pEp):
+    bdata = b'this is binary \x00\x01\xbb\xa7\xa4\xab test data'
+    b = pEp.Blob(b'dummy', 'application/x-mydata', 'myfile.dat')
+    b.data = bdata
+    assert b.data == bdata
+    assert b.mime_type == 'application/x-mydata'
+    assert b.filename == 'myfile.dat'