function(set_fatal_error err)
    set(Z_VCPKG_UNIT_TEST_HAS_FATAL_ERROR "ON" CACHE BOOL "" FORCE)
    set(Z_VCPKG_UNIT_TEST_FATAL_ERROR "${err}" CACHE STRING "" FORCE)
endfunction()
function(unset_fatal_error)
    set(Z_VCPKG_UNIT_TEST_HAS_FATAL_ERROR "OFF" CACHE BOOL "" FORCE)
endfunction()
function(set_has_error)
    set(Z_VCPKG_UNIT_TEST_HAS_ERROR ON CACHE BOOL "" FORCE)
endfunction()

macro(message level msg)
    if("${level}" STREQUAL "FATAL_ERROR")
        set_fatal_error("${msg}")
        return()
    else()
        _message("${level}" "${msg}") # note: this results in incorrect printing, but that's fine
        # message(STATUS "\${asdf}") will result in
        # message(STATUS "${asdf}"), since that's how macro arguments work.
    endif()
endmacro()

set(Z_VCPKG_UNIT_TEST_HAS_ERROR OFF CACHE BOOL "" FORCE)
unset_fatal_error()

# in order to allow namespacing
function(unit_test_match namespace value regex)
    if("${value}" MATCHES "${regex}")
        set("${namespace}_MATCHED" ON PARENT_SCOPE)
        if("${CMAKE_MATCH_COUNT}" EQUAL "0")
            return()
        endif()

        foreach(match RANGE 1 "${CMAKE_MATCH_COUNT}")
            set("${namespace}_CMAKE_MATCH_${match}" "${CMAKE_MATCH_${match}}" PARENT_SCOPE)
        endforeach()
    else()
        set("${namespace}_MATCHED" OFF PARENT_SCOPE)
    endif()
endfunction()

function(unit_test_check_variable_unset utcvu_test utcvu_variable)
    cmake_language(EVAL CODE "${utcvu_test}")
    if(Z_VCPKG_UNIT_TEST_HAS_FATAL_ERROR)
        unset_fatal_error()
        set_has_error()
        message(STATUS "${utcvu_test} had an unexpected FATAL_ERROR;
    expected: \"${utcvu_value}\"")
        message(STATUS "FATAL_ERROR: ${Z_VCPKG_UNIT_TEST_FATAL_ERROR}")
        return()
    endif()

    unit_test_match(utcvu "${utcvu_variable}" [[^(ENV|CACHE)\{(.*)\}$]])
    if(utcvu_MATCHED)
        message(STATUS "utcvu_variable: ${utcvu_CMAKE_MATCH_2}")
        if("${utcvu_CMAKE_MATCH_1}" STREQUAL "ENV")
            set(utcvu_actual_value "$ENV{${utcvu_CMAKE_MATCH_2}}")
        elseif("${utcvu_CMAKE_MATCH_1}" STREQUAL "CACHE")
            set(utcvu_actual_value "$CACHE{${utcvu_CMAKE_MATCH_2}}")
        else()
            _message(FATAL_ERROR "unexpected value for CMAKE_MATCH_1: ${utcvu_CMAKE_MATCH_1}")
        endif()
    else()
        set(utcvu_actual_value "${${utcvu_variable}}")
    endif()

    if(DEFINED "${utcvu_variable}")
        message(STATUS "${utcvu_test} set ${utcvu_variable};
    expected: \"${utcvu_variable}\" unset
    actual  : \"${utcvu_actual_value}\"")
        set_has_error()
        return()
    endif()
endfunction()

function(unit_test_check_variable_equal utcve_test utcve_variable utcve_value)
    cmake_language(EVAL CODE "${utcve_test}")
    if(Z_VCPKG_UNIT_TEST_HAS_FATAL_ERROR)
        unset_fatal_error()
        set_has_error()
        message(STATUS "${utcve_test} had an unexpected FATAL_ERROR;
    expected: \"${utcve_value}\"")
        message(STATUS "FATAL_ERROR: ${Z_VCPKG_UNIT_TEST_FATAL_ERROR}")
        return()
    endif()

    if(NOT DEFINED "${utcve_variable}" AND NOT "${utcve_variable}" MATCHES "^ENV\\{")
        message(STATUS "${utcve_test} failed to set ${utcve_variable};
    expected: \"${utcve_value}\"")
        set_has_error()
        return()
    endif()

    unit_test_match(utcve "${utcve_variable}" [[^(ENV|CACHE)\{(.*)\}$]])
    if(utcve_MATCHED)
        if("${utcve_CMAKE_MATCH_1}" STREQUAL "ENV")
            set(utcve_actual_value "$ENV{${utcve_CMAKE_MATCH_2}}")
        elseif("${utcve_CMAKE_MATCH_1}" STREQUAL "CACHE")
            set(utcve_actual_value "$CACHE{${utcve_CMAKE_MATCH_2}}")
        else()
            _message(FATAL_ERROR "unexpected value for CMAKE_MATCH_1: ${utcve_CMAKE_MATCH_1}")
        endif()
    else()
        set(utcve_actual_value "${${utcve_variable}}")
    endif()

    if(NOT "${utcve_actual_value}" STREQUAL "${utcve_value}")
        message(STATUS "${utcve_test} resulted in the wrong value for ${utcve_variable};
    expected: \"${utcve_value}\"
    actual  : \"${utcve_actual_value}\"")
        set_has_error()
        return()
    endif()
endfunction()

function(unit_test_ensure_success utcve_test)
    cmake_language(EVAL CODE "${utcve_test}")
    if(Z_VCPKG_UNIT_TEST_HAS_FATAL_ERROR)
        set_has_error()
        message(STATUS "${utcve_test} was expected to be successful.")
    endif()
    unset_fatal_error()
endfunction()
function(unit_test_ensure_fatal_error utcve_test)
    cmake_language(EVAL CODE "${utcve_test}")
    if(NOT Z_VCPKG_UNIT_TEST_HAS_FATAL_ERROR)
        set_has_error()
        message(STATUS "${utcve_test} was expected to be a FATAL_ERROR.")
    endif()
    unset_fatal_error()
endfunction()

set(VCPKG_POLICY_EMPTY_PACKAGE enabled)

if("minimum-required" IN_LIST FEATURES)
    include("${CMAKE_CURRENT_LIST_DIR}/test-vcpkg_minimum_required.cmake")
endif()
if("list" IN_LIST FEATURES)
    include("${CMAKE_CURRENT_LIST_DIR}/test-vcpkg_list.cmake")
endif()
if("host-path-list" IN_LIST FEATURES)
    include("${CMAKE_CURRENT_LIST_DIR}/test-vcpkg_host_path_list.cmake")
endif()
if("function-arguments" IN_LIST FEATURES)
    include("${CMAKE_CURRENT_LIST_DIR}/test-z_vcpkg_function_arguments.cmake")
endif()
if("merge-libs" IN_LIST FEATURES)
    include("${CMAKE_CURRENT_LIST_DIR}/test-z_vcpkg_cmake_config_fixup_merge.cmake")
endif()

if(Z_VCPKG_UNIT_TEST_HAS_ERROR)
    _message(FATAL_ERROR "At least one test failed")
endif()