diff --git a/tests/test_base_template.py b/tests/test_base_template.py
index 887be71a..509a5195 100644
--- a/tests/test_base_template.py
+++ b/tests/test_base_template.py
@@ -79,64 +79,64 @@ def test_include_placeholder_in_missing_data_if_placeholder_is_conditional(perso
         (
             "the quick brown fox",
             "jumps",
-            []
+            set()
         ),
         (
             "the quick ((colour)) fox",
             "jumps",
-            ["colour"]
+            {"colour"}
         ),
         (
             "the quick ((colour)) ((animal))",
             "jumps",
-            ["colour", "animal"]
+            {"colour", "animal"}
         ),
         (
             "((colour)) ((animal)) ((colour)) ((animal))",
             "jumps",
-            ["colour", "animal"]
+            {"colour", "animal"}
         ),
         (
             "the quick brown fox",
             "((colour))",
-            ["colour"]
+            {"colour"}
         ),
         (
             "the quick ((colour)) ",
             "((animal))",
-            ["animal", "colour"]
+            {"animal", "colour"}
         ),
         (
             "((colour)) ((animal)) ",
             "((colour)) ((animal))",
-            ["colour", "animal"]
+            {"colour", "animal"}
         ),
         (
             "Dear ((name)), ((warning?? This is a warning))",
             "",
-            ["name", "warning"]
+            {"name", "warning"}
         ),
         (
             # Placeholder names are limited to alphanumeric characters, spaces and dashes
             "((warning? one question mark))",
             "",
-            []
+            set()
         ),
         (
             "Dear ((name)), ((warning?? This is a warning {}))",
             "",
-            ["name", "warning"]
+            {"name", "warning"}
         ),
         (
             "A conditional url: ((has_url?? [some link](http://test.me) ))",
             "",
-            ["has_url"]
+            {"has_url"}
         ),
     ]
 )
 def test_extracting_placeholders(template_content, template_subject, expected):
     got = WithSubjectTemplate({"content": template_content, 'subject': template_subject}).placeholders
-    assert got == expected
+    assert WithSubjectTemplate({"content": template_content, 'subject': template_subject}).placeholders == expected
 
 
 @pytest.mark.parametrize('template_cls', [SMSMessageTemplate, SMSPreviewTemplate])