Closes #162

Makefile

@@ -13,8 +13,8 @@ test-cargo:
 	cargo test --release
 
 format:
+	$(UV) run ruff check --fix
 	$(UV) run ruff format
-	$(UV) run ruff check
 
 lint:
 	$(UV) run ruff check --exit-non-zero-on-fix

docs/data-structures/trie.md

@@ -88,7 +88,7 @@ Checks if a word has been inserted into the trie.
 t = Trie()
 t.insert("apple")
 assert t.search("apple") == True
-assert t.search("app")   == False
+assert t.search("app") == False
 ```
 
 ---
@@ -111,7 +111,7 @@ Checks if any inserted word starts with the given prefix.
 t = Trie()
 t.insert("apple")
 t.insert("application")
-assert t.starts_with("app")  == True
+assert t.starts_with("app") == True
 assert t.starts_with("appl") == True
 assert t.starts_with("banana") == False
 assert t.starts_with("") == True
@@ -140,7 +140,7 @@ t.insert("app")
 
 assert t.delete("apple") == True
 assert t.delete("apple") == False
-assert t.search("app")   == True
+assert t.search("app") == True
 ```
 
 ---

fast_collections/__init__.pyi

@@ -22,7 +22,6 @@ class Trie:
 
     def __init__(self) -> None:
         """Initialize an empty trie."""
-        ...
 
     def insert(self, word: str) -> None:
         """
@@ -45,7 +44,6 @@ class Trie:
             >>> "hello" in t
             True
         """
-        ...
 
     def search(self, word: str) -> bool:
         """
@@ -70,7 +68,6 @@ class Trie:
             >>> t.search("app")
             False
         """
-        ...
 
     def starts_with(self, prefix: str) -> bool:
         """
@@ -95,7 +92,6 @@ class Trie:
             >>> t.starts_with("app")
             True
         """
-        ...
 
     def delete(self, word: str) -> bool:
         """
@@ -123,7 +119,6 @@ class Trie:
             >>> t.delete("apple")
             True
         """
-        ...
 
     def word_count(self) -> int:
         """
@@ -140,7 +135,6 @@ class Trie:
             >>> t.word_count()
             1
         """
-        ...
 
     def collect_words(self) -> list[str]:
         """
@@ -163,7 +157,6 @@ class Trie:
             >>> t.collect_words()
             ['apple', 'banana']
         """
-        ...
 
     def __contains__(self, word: str) -> bool:
         """
@@ -179,7 +172,6 @@ class Trie:
             >>> "app" in t
             False
         """
-        ...
 
     def __len__(self) -> int:
         """
@@ -194,4 +186,3 @@ class Trie:
             >>> len(t)
             2
         """
-        ...

tests/conftest.py

@@ -0,0 +1,8 @@
+import pytest
+
+from fast_collections import Trie
+
+
+@pytest.fixture
+def trie():
+    return Trie()

tests/test_trie.py

@@ -0,0 +1,64 @@
+import pytest
+
+
+def _insert_all(trie, words):
+    for w in words:
+        trie.insert(w)
+
+
+@pytest.mark.parametrize(
+    "words", [[], ["hello"], ["hello", "world"], ["", "a", "b", "c"], ["a", "a", "b"]]
+)
+def test_size_and_word_count(trie, words):
+    "Test that the trie has the correct size and word count"
+    _insert_all(trie, words)
+    expected = len(set(words))
+    assert len(trie) == expected
+    assert trie.word_count() == expected
+
+
+@pytest.mark.parametrize(
+    "words, present, absent",
+    [
+        (
+            [
+                "hello",
+            ],
+            [
+                "hello",
+            ],
+            ["hell", "world"],
+        ),
+        ([], [], ["hello"]),
+        (["a", "b", "c"], ["a", "b", "c"], []),
+        (["a", "a", "b"], ["a", "b"], ["c"]),
+    ],
+)
+def test_contains(trie, words, present, absent):
+    "Test that the trie contains the correct words"
+    _insert_all(trie, words)
+
+    for w in present:
+        assert w in trie
+
+    for w in absent:
+        assert w not in trie
+        assert not trie.search(w)
+
+
+@pytest.mark.parametrize(
+    "words, prefix, expected",
+    [
+        (["hello"], "hello", True),
+        (["hello"], "hell", True),
+        (["hello"], "h", True),
+        (["hello"], "", True),
+        (["hello"], "help", False),
+        (["hello", "world"], "wo", True),
+        (["hello", "world"], "worl", True),
+        (["hello", "world"], "x", False),
+    ],
+)
+def test_starts_with(trie, words, prefix, expected):
+    _insert_all(trie, words)
+    assert trie.starts_with(prefix) is expected