diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/froude_test.py b/tests/froude_test.py
new file mode 100644
index 0000000..5b36462
--- /dev/null
+++ b/tests/froude_test.py
@@ -0,0 +1,11 @@
+import pytest
+from scaling import froude
+
+def test_unit_to_same_unit():
+    assert froude.model_to_proto(1, 1, 'm', 'm') == 1
+
+def test_froude_length():
+    assert froude.model_to_proto(1, 10, 'm', 'm') == 10
+
+def test_froude_force():
+    assert froude.model_to_proto(1, 10, 'N', 'N') == 1000