Can I get some advice about how should I solve this problem, I really have no idea what's been causing the issue from passing these tests.

So here's the test result message:

TestMap::test$\_$access$\_$standardLeftRead$()$

line:$1603$ condition:s $==$ int$(30)$

line:$1608$ condition:m$.$bst$.$numElements $==3$

line:$1608$ condition:m$.$bst$.$root$->$pLeft$->$pRight $==$ nullptr

TestMap::test$\_$access$\_$standardLeftWrite$()$

line:$1690$ condition:m$.$bst$.$root$->$pLeft$->$data.second $==$ int$(33)$

line:$1693$ condition:m$.$bst$.$numElements $==3$

line:$1693$ condition:m$.$bst$.$root$->$pLeft$->$pRight $==$ nullptr

TestMap::test$\_$access$\_$standardRightRead$()$

line:$1627$ condition:s $==$ int$(70)$

line:$1632$ condition:m$.$bst$.$numElements $==3$

line:$1632$ condition:m$.$bst$.$root$->$pRight$->$pRight $==$ nullptr

TestMap::test$\_$access$\_$standardRightWrite$()$

line:$1721$ condition:m$.$bst$.$root$->$pRight$->$data.second $==$ int$(77)$

line:$1724$ condition:m$.$bst$.$numElements $==3$

line:$1724$ condition:m$.$bst$.$root$->$pRight$->$pRight $==$ nullptr

TestMap::test$\_$access$\_$standardRootRead$()$

line:$1579$ condition:s $==$ int$(50)$

line:$1584$ condition:m$.$bst$.$numElements $==3$

line:$1584$ condition:m$.$bst$.$root$->$pRight$->$pLeft $==$ nullptr

TestMap::test$\_$access$\_$standardRootWrite$()$

line:$1659$ condition:m$.$bst$.$root$->$data.second $==$ int$(55)$

line:$1662$ condition:m$.$bst$.$numElements $==3$

line:$1662$ condition:m$.$bst$.$root$->$pRight$->$pLeft $==$ nullptr

And here's the code I think that need to improve:

$/*****************************************************$

$*$ MAP :: ACCESS

$****************************************************/$

template

const V& map::operator$[]($const K& k$)$ const

$\{$

auto it $=$ bst$.$find$($Pairs$($k$,$ V$()))$;

if $($it $==$ bst$.$end$())$

throw std::out$\_$of$\_$range$("$invalid map key"$)$;

return $(*$it$).$second;

$\}$

template

V& map::operator$[]($const K& k$)$

$\{$

auto result $=$ bst$.$insert$($Pairs$($k$,$ V$()))$;

return const$\_$cast$((*$result$.$first$).$second$)$;

$\}$

template

const V& map::at$($const K& k$)$ const

$\{$

auto it $=$ bst$.$find$($Pairs$($k$,$ V$()))$;

if $($it $==$ bst$.$end$())$

throw std::out$\_$of$\_$range$("$invalid map key"$)$;

return it$.$operator$*().$second;

$\}$

template

V& map::at$($const K& k$)$

$\{$

auto it $=$ bst$.$find$($Pairs$($k$,$ V$()))$;

if $($it $==$ bst$.$end$())$

throw std::out$\_$of$\_$range$("$invalid map key"$)$;

return const$\_$cast$($it$.$operator$*().$second$)$;

$\}$

template

typename map::iterator map::find$($const K& k$)$

$\{$

return iterator$($bst$.$find$($Pairs$($k$,$ V$())))$;

$\}$

$/*****************************************************$

$*$ MAP :: INSERT

$****************************************************/$

template

custom::pair::iterator, bool$>$ map::insert$($const Pairs& rhs$)$

$\{$

auto result $=$ bst$.$insert$($rhs$)$;

return custom::pair$($iterator$($result$.$first$),$ result.second$)$;

$\}$

template

custom::pair::iterator, bool$>$ map::insert$($Pairs&& rhs$)$

$\{$

auto result $=$ bst$.$insert$($std::move$($rhs$))$;

return custom::pair$($iterator$($result$.$first$),$ result.second$)$;

$\}$

template

template

void map::insert$($Iterator first, Iterator last$)$

$\{$

for $($auto it $=$ first; it $!=$ last; $++$it$)$

bst$.$insert$(*$it$)$;

$\}$

template

void map::insert$($const std::initializer$\_$list & il$)$

$\{$

insert$($il$.$begin$(),$ il$.$end$())$;

$\}$