diff --git a/test/test_spec.py b/test/test_spec.py
new file mode 100644
index 0000000..919fc36
--- /dev/null
+++ b/test/test_spec.py
@@ -0,0 +1,35 @@
+from pathlib import Path
+
+import pytest
+
+from speccpu import find_build
+
+
+class TestFindBuild:
+    def test_find_build_success(self, tmpdir):
+        # Create a mock directory structure with a build directory
+        build_parent = Path(tmpdir)
+        build_dir = build_parent / "build_2023"
+        build_dir.mkdir()
+
+        # Test that find_build correctly identifies the build directory
+        found_dir = find_build(build_parent)
+        assert found_dir == build_dir
+
+    def test_find_build_multiple_dirs(self, tmpdir):
+        # Create multiple build directories
+        build_parent = Path(tmpdir)
+        build_dir1 = build_parent / "build_2022"
+        build_dir2 = build_parent / "build_2023"
+        build_dir1.mkdir()
+        build_dir2.mkdir()
+
+        # Should find the alphabetically first one
+        found_dir = find_build(build_parent)
+        assert found_dir == build_dir1
+
+    def test_find_build_no_dir(self, tmpdir):
+        # Test the error case when no build directory exists
+        build_parent = Path(tmpdir)
+        with pytest.raises(RuntimeError):
+            find_build(build_parent)