Add a unit test app + example tests

src/drivers/test/CMakeLists.txt

@@ -0,0 +1 @@
+idf_component_register(SRC_DIRS "." INCLUDE_DIRS "." REQUIRES cmock drivers)

src/drivers/test/test_example.cpp

@@ -0,0 +1,9 @@
+#include "unity.h"
+
+TEST_CASE("Example test case", "[cooltag]") {
+    TEST_ASSERT_EQUAL(0, 0);
+}
+
+TEST_CASE("test that doesn't run", "[cooltag][ignore]") {
+    TEST_ASSERT_EQUAL(0, 1);
+}