function addChar$($input$,$character$)\{$

$$if$($input$.$value $==$null $||$input$.$value $=="0")$

$$ input.value $=$character

$$else

$$ input.value $+=$character

$\}$

function cos$($form$)\{$

$$form$.$display.value $=$Math$.$cos$($form$.$display.value$)$;

$\}$

function sin$($form$)\{$

$$form$.$display.value $=$Math$.$sin$($form$.$display.value$)$;

$\}$

function tan$($form$)\{$

$$form$.$display.value $=$Math$.$tan$($form$.$display.value$)$;

$\}$

function sqrt$($form$)\{$

$$form$.$display.value $=$Math$.$sqrt$($form$.$display.value$)$;

$\}$

function ln$($form$)\{$

$$form$.$display.value $=$Math$.$log$($form$.$display.value$)$;

$\}$

function exp$($form$)\{$

$$form$.$display.value $=$Math$.$exp$($form$.$display.value$)$;

$\}$

function deleteChar$($input$)\{$

$$input$.$value $=$input$.$value.substring$(0,$input$.$value.length $-1)$

$\}$

var val $=0\mathrm{.}0$;

function percent$($input$)\{$

$$ val $=$input$.$value;

$$ input.value $=$input$.$value $+"\%"$;

$\}$

function changeSign$($input$)\{$

$$if$($input$.$value.substring$(0,1)=="-")$

$$ input.value $=$input$.$value.substring$(1,$input$.$value.length$)$

$$else

$$ input.value $="-"+$input$.$value

$\}$

function compute$($form$)\{$

$//$if $($val $!==0\mathrm{.}0)\{$

$//$var percent $=$form$.$display.value;

$//$percent $=$pcent$.$substring$($percent$.$indexOf$("\%")+1)$;

$//$form$.$display.value $=$parseFloat$($percent$)/100*$val;

$//$val $=0\mathrm{.}0$;

$//\}$else

$$ form.display.value $=$eval$($form$.$display.value$)$;

$\}$

function square$($form$)\{$

$$form$.$display.value $=$eval$($form$.$display.value$)*$eval$($form$.$display.value$)$

$\}$

function checkNum$($str$)\{$

$$for $($var i $=0$; i $<$str$.$length; i$++)\{$

$$ var ch $=$str$.$charAt$($i$)$;

$$ if $($ch $<"0"||$ch $>"9")\{$

$$ if $($ch $!="/"$&& ch $!="*"$&& ch $!="+"$&& ch $!="-"$&& ch $!="."$

$$ && ch $!="("$&& ch$!=")"$&& ch $!="\%")\{$

$$ alert$("$invalid entry!"$)$

$$ return false

$\}$

$\}$

$\}$

$$ return true

$\}$

In this part you are to develop a set of unit tests for a scientific calculator program written in JavaScript above. At first run the program. Try to use it to calculate some expressions. Then try to understand how does it work. Finally:

a$)$Write a total of $9$ TESTS, organized into THREE sets.

b$)$ Each test set should target one functional element of the program $($You CANNOT choose addition, subtraction, division and multiplication$)$

c$)$WRITE the code that allows the program to PASS your tests.

d$)$ Explain your APPROACH in each test set. What was your STRATEGY here?

e$)$ Capture screenshots or console logs of the code BEFORE and AFTER it passed the tests, showing the OUTPUT of the unit testing library. $($THIS IS A MUST SO PLEASE INCLUDE THIS$)$

f$)$Shorten the output to the most important part, where it LISTS the number of tests passed and failed.

ALREADY $4-5$ ANSWERS ARE GIVEN ON CHEGG BUT ARE WRONG SO DO NOT COPY.