TEST(QueryProjectionTest, ExclusionProjectionPreservesNonExcludedFields) {
    auto proj = createProjection("{}", "{a: 0}");
    ASSERT_TRUE(proj.isFieldRetainedExactly("c"));
}
TEST(QueryProjectionTest, ExclusionProjectionPreservesNonExcludedFields) {
    auto proj = createProjection("{}", "{a: 0}");
    ASSERT_TRUE(proj.isFieldRetainedExactly("c"));
}