diff --git a/modoboa/webmail/tests/test_lib_imaputils.py b/modoboa/webmail/tests/test_lib_imaputils.py
new file mode 100644
index 000000000..6eab742e1
--- /dev/null
+++ b/modoboa/webmail/tests/test_lib_imaputils.py
@@ -0,0 +1,27 @@
+"""mailutils tests"""
+
+import io
+import unittest
+
+from modoboa.webmail.lib.imaputils import IMAPconnector
+
+
+class ImapUtilsTestCase(unittest.TestCase):
+    """Test mail utils library"""
+
+    def setUp(self):
+        self.imap_connector = IMAPconnector(user="test", password="test")
+
+    def test_criterions_one_criterion_with_pattern(self):
+        """Test with Criterion and pattern"""
+        self.imap_connector.criterions = []
+        self.imap_connector.parse_search_parameters("from_addr", "bob")
+        result = [bytearray('FROM "bob"', "utf8")]
+        self.assertEqual(self.imap_connector.criterions, result)
+
+    def test_criterions_one_criterion_without_pattern(self):
+        """Test with Criterion and pattern"""
+        self.imap_connector.criterions = []
+        self.imap_connector.parse_search_parameters("SEEN", "")
+        result = [bytearray("ALL", "utf8")]
+        self.assertEqual(self.imap_connector.criterions, result)
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