tests: add Common placeholder smoke/gtest tests and MockCoordTrans

Lts/Common/CommonUnitTestsPlaceholder/coordTransTests_gtest.cpp

@@ -0,0 +1,12 @@
+#include "mocks/MockCoordTrans.h"
+#include <gtest/gtest.h>
+
+TEST(CoordTransGTest, ForwardInverseRoundtrip) {
+  auto p = MockCoordTrans::forward(1.2345, 2.3456);
+  EXPECT_NEAR(p.first, 1.2345 * 111000.0, 1e-6);
+  EXPECT_NEAR(p.second, 2.3456 * 111000.0, 1e-6);
+
+  auto inv = MockCoordTrans::inverse(p.first, p.second);
+  EXPECT_NEAR(inv.first, 1.2345, 1e-9);
+  EXPECT_NEAR(inv.second, 2.3456, 1e-9);
+}