TEST(QueryProjectionTest, InclusionProjectionPreservesChild) {
    auto proj = createProjection("{}", "{a: 1}");
    ASSERT_TRUE(proj.isFieldRetainedExactly("a.b"));
}
TEST(QueryProjectionTest, InclusionProjectionPreservesChild) {
    auto proj = createProjection("{}", "{a: 1}");
    ASSERT_TRUE(proj.isFieldRetainedExactly("a.b"));
}