diff --git a/.drone.yml b/.drone.yml
index 50b299b..920f110 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -7,8 +7,7 @@ steps:
   image: python:3
   commands:
     - pip install mypy pytest
-    - mypy bytetrie/bytetrie.py
-    - mypy bytetrie/util.py
+    - mypy bytetrie/*.py
     - python -m pytest
 
 - name: publish
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..aae94a5
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,5 @@
+import pytest
+
+pytest_plugins = [
+   "tries.simple_trie"
+]
diff --git a/tests/test_bytetrie_blackbox.py b/tests/test_bytetrie_blackbox.py
new file mode 100644
index 0000000..19f84a8
--- /dev/null
+++ b/tests/test_bytetrie_blackbox.py
@@ -0,0 +1,49 @@
+import pytest
+
+import sys
+import os
+sys.path.append("tests/tries/")
+
+from bytetrie import ByteTrie
+
+import simple_trie
+
+def test_find_all(simple_trie):
+    r = simple_trie.find(b"A")
+    ls = [n.value() for n in r]
+    expected = ["A", "AA", "AACDEGG", "AACDEF", "AACDEH", "AB", "ABCDE"]
+    not_expected = ["AACDE"]
+
+    for e in expected:
+        assert e in ls
+    for ne in not_expected:
+        assert not ne in ls
+
+def test_find_single_terminal(simple_trie):
+    r = simple_trie.find(b"AACDEH")
+    assert len(r) == 1
+    assert r[0].value() == "AACDEH"
+    assert r[0].key() == b"AACDEH"
+
+def test_unknown_prefix_empty(simple_trie):
+    r = simple_trie.find(b"AAD")
+    assert len(r) == 0
+
+def test_partial_prefix_find_subnodes(simple_trie):
+    r = simple_trie.find(b"AACD")
+    ls = [n.value() for n in r]
+
+    expected = ["AACDEGG", "AACDEF", "AACDEH"]
+    not_expected = ["A", "AA", "AB", "ABCDE", "AACDE"]
+
+    assert len(r) == 3
+    for e in expected:
+        assert e in ls
+    for ne in not_expected:
+        assert not ne in ls
+
+def test_partial_prefix_find_terminal(simple_trie):
+    r = simple_trie.find(b"ABC")
+    assert len(r) == 1
+    assert r[0].key() == b"ABCDE"
+    assert r[0].value() == "ABCDE"
diff --git a/tests/tries/simple_trie.png b/tests/tries/simple_trie.png
new file mode 100644
index 0000000..aac579d
Binary files /dev/null and b/tests/tries/simple_trie.png differ
diff --git a/tests/tries/simple_trie.py b/tests/tries/simple_trie.py
new file mode 100644
index 0000000..1b48c86
--- /dev/null
+++ b/tests/tries/simple_trie.py
@@ -0,0 +1,28 @@
+"""
+Create a simple ByteTrie fixture for testing basic functionality. Without edge
+cases. Single-valued.
+
+See simple_trie.png
+"""
+
+import pytest
+
+from bytetrie import ByteTrie
+
+def insert(trie):
+    """ Shall only be used to insert strings """
+    t = trie
+    def _insert(*vals):
+        for val in vals:
+            t.insert(val.encode('utf-8'), val)
+    return _insert
+
+@pytest.fixture
+def simple_trie():
+    t = ByteTrie()
+    ins = insert(t)
+    ins("A")
+    ins("AA", "AB")
+    ins("ABCDE")
+    ins("AACDEF", "AACDEGG", "AACDEH")
+    return t