diff --git a/tests/test_core.py b/tests/test_core.py
index 33fd53845..3daedc5b7 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -49,6 +49,20 @@ class TestStateProxy:
 
     sp = StateProxy(raw_state_dict)
 
+    @classmethod
+    def count_initial_mutations(cls, d, count=0):
+        """
+        Counts the number of mutations that will be performed for a given dictionary
+        when it is converted into a StateProxy.
+        """
+        for key, value in d.items():
+            if not key.startswith('_'):
+                count += 1  # Increment for each key-value pair
+                if isinstance(value, dict):
+                    count = TestStateProxy.count_initial_mutations(value, count)
+                    # Recurse for nested dictionaries
+        return count
+
     def test_read(self) -> None:
         d = self.sp.to_dict()
         assert d.get("name") == "Robert"
@@ -57,10 +71,31 @@ def test_read(self) -> None:
         assert d.get("utfࠀ") == 23
 
     def test_mutations(self) -> None:
+        m = self.sp.get_mutations_as_dict()
+        assert len(m) == TestStateProxy.count_initial_mutations(self.sp.to_dict())
+        # Mutated after initialization from raw_state_dict
+
         self.sp["age"] = 2
-        self.sp["interests"].append("dogs")
+        m = self.sp.get_mutations_as_dict()
+        assert m.get("age") == 2
+        assert len(m) == 1
+
+        self.sp["interests"] += ["dogs"]
         self.sp["features"]["height"] = "short"
+        m = self.sp.get_mutations_as_dict()
+        assert m.get("interests") == ["lamps", "cars", "dogs"]
+        assert m.get("features.height") == "short"
+        assert len(m) == 2
+
         self.sp["state.with.dots"]["photo.jpeg"] = "Corrupted"
+        m = self.sp.get_mutations_as_dict()
+        assert m.get("state\\.with\\.dots.photo\\.jpeg") == "Corrupted"
+        assert len(m) == 1
+
+        self.sp["new.state.with.dots"] = {"test": "test"}
+        m = self.sp.get_mutations_as_dict()
+        assert len(m) == 1
+
         d = self.sp.to_dict()
         assert d.get("age") == 2
         assert d.get("interests") == ["lamps", "cars", "dogs"]
@@ -70,8 +105,7 @@ def test_mutations(self) -> None:
         self.sp.apply("age")
         m = self.sp.get_mutations_as_dict()
         assert m.get("age") == 2
-        assert m.get("features.height") == "short"
-        assert m.get("state\\.with\\.dots.photo\\.jpeg") == "Corrupted"
+        assert len(m) == 1
 
     def test_private_members(self) -> None:
         d = self.sp.to_dict()