basic behavior working

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "add-only-dictionary"
-version = "0.1.1"
+version = "0.1.2"
 description = "Add Only Dictionary"
 authors = ["Matt Koski <[email protected]>"]
 license = "MIT"

src/add_only_dictionary/aodict.py

@@ -13,5 +13,11 @@ class AODict(Dict[K, V]):
     """AODict class."""
 
     def __setitem__(self, k: K, v: V) -> None:
-        """__setitem__."""
-        super().__setitem__(k, v)
+        """Lets you add item to dict, but not if key exists.
+
+        Args:
+            k (K): the key of attempted addition
+            v (V): the value
+        """
+        if k not in self.keys():
+            super().__setitem__(k, v)

tests/test_aodict.py

@@ -3,6 +3,15 @@
 
 
 def test_instantiate() -> None:
-    """Just a sanity check to see if AODict can be created."""
+    """Just a sanity check to see if AODict works."""
     ao: AODict[str, int] = AODict()
     ao["a"] = 1
+    assert ao["a"] == 1
+
+
+def test_no_overwrite() -> None:
+    """Make sure if the key is already in the dict, it can't be updated."""
+    ao: AODict[str, int] = AODict()
+    ao["a"] = 1
+    ao["a"] = 2
+    assert ao["a"] == 1