TEST(QueryProjectionTest, PositionalProjectionDoesNotPreserveChild) {
    auto proj = createFindProjection("{a: {$elemMatch: {$eq: 0}}}", "{'a.$': 1}");
    ASSERT_FALSE(proj.isFieldRetainedExactly("a.b"));
}
TEST(QueryProjectionTest, PositionalProjectionDoesNotPreserveChild) {
    auto proj = createFindProjection("{a: {$elemMatch: {$eq: 0}}}", "{'a.$': 1}");
    ASSERT_FALSE(proj.isFieldRetainedExactly("a.b"));
}