Unittests for esphome python code (#931)

tests/unit_tests/strategies.py

@@ -0,0 +1,15 @@
+from typing import Text
+
+import hypothesis.strategies._internal.core as st
+from hypothesis.strategies._internal.strategies import SearchStrategy
+
+
+@st.defines_strategy_with_reusable_values
+def mac_addr_strings():
+    # type: () -> SearchStrategy[Text]
+    """A strategy for MAC address strings.
+
+    This consists of six strings representing integers [0..255],
+    without zero-padding, joined by dots.
+    """
+    return st.builds("{:02X}:{:02X}:{:02X}:{:02X}:{:02X}:{:02X}".format, *(6 * [st.integers(0, 255)]))