Baldi's Basics Plus : The Test Demonstration.

Here is the full video of how The Test Works in Baldi's Basics Plus Game.

P.S. I do not own this thumbnail of The Test. Credits goes to the Youtuber Olyantwo for making that thumbnail.

The Test is an odd character in Baldi's Basics Plus. He can only appear in Floor 3, as well as in some Endless Mode seeds.

The Test will rarely spawn in the hallways on Floor 3. When the Player enters The Test's line of sight, The Test will produce an unusual and weird humming noise, the lights will flicker around him and all other characters, including Baldi, will stop in place. These effects cease as soon as the Player exits his line of sight.

When he sees the Player for the first time, he will begin a 5-second countdown, during which he is unable to move (aside from turning his head to constantly look at the Player). During the countdown, his head will also slowly move upwards until it is in its intended position. Once this 5-second countdown is over, The Test will gain the ability to move. He will only move while the Player is not looking at him, and while the Player is still in The Test's line of sight. However, he moves 10 times faster than Arts and Crafters at maximum speed, meaning that if the Player looks away for even a split second while still in The Test's line of sight, they will be caught almost instantly, unless they use the BSODA just before he starts chasing them.

If The Test makes contact with the Player while the Player is not looking at him, his body will disappear, leaving only his head behind. Then, for the next two minutes, the Player is "blinded", covering most of the school with a black mist. This "blind" effect is similar to the fog event, except it is much stronger and it does not allow the Player to see silhouettes of faraway objects. It also only affects the Player, meaning other characters such as Baldi can still see normally.

Once this effect is over, The Test's body will reappear in a random location in the hallway, and the process will repeat from the beginning. Unlike Arts and Crafters, there is no limit to how many times the Player can be blinded by The Test in a single game.

[GreenStarHB]

How the test works (i think):

When you see him, no need to worry, the other characters will be frozen. The only thing you have to worry about it leaving. Keep sight on him, and GO! Once you exit his line of sight, you are safe.

[zxxbtmi]

Did they like, remove him from the 0.3.8 version? I cannot find the test at all, not even on seeds where he apparently spawns.

[sergiocollazo-cruz]

The test is so creepy he made everything dark for long time

[Strykore_The_Wolf]

The Test has a roblox body, some stick arms and legs, a KFC chicken wing head, some teleporting ice skating shoes, and Mickey Mouse gloves

[DavidCEO]

In my opinion it functions a bit like Herobrine from the From the Fog mod for Minecraft appearing behind walls or behind you but also a bit like SCP-173 but with the the arts and crafters blinding ability but now on steroids.
Edit:
The blinding mechanic is more similar to the fog event in Baldi's Basics+ but now the fog is only visible to you and it's black and does not effect other enemies.

[thatoneguy]

The Test: When you spot him he'll wind up for a couple seconds. After his wind up, looking at him and looking away causes him to rush towards you. (He is the fastest character in the game) If you exit his line of sight, you are safe until you look at him again. If he catches you and you aren't looking at him, he'll blind you, and only you, for several minutes. I'm pretty sure after you encounter him and he doesn't blind you, he's supposed to rush towards you without waiting for the character to notice him, (hence why you should 'remember where you last spotted him) but he doesn't for me.

[robloxdude]

hes like scp 173 except he doesnt kill you

[Panceggs]

Oh this is why they said to remeber were is he.