Susannah "Susan" Laura and Marrionette "Mary" Louise Test (a.k.a. The Test Twins, The Test Sisters, The Test Girls) are the 13-14-year-old older twin sisters of Johnny Test who are notorious in the series for making great scientific inventions to help Johnny with whatever problem he as and to keep him safe at the same time. They are also notorious for having a crush on their next-door neighbor, Gil Nexdor.
Why They Are Such Geniuses
- As mentioned above, they are scandalous for making fascinating and ingenious scientific inventions they often use to test them on Johnny, as well as generating ones that help Johnny solve problems he is facing and keep him safe.
- They both have a great twin-sister relationship with each other.
- They are excruciatingly highly intelligent and the smartest members of the Test family, mostly when it comes to science.
- They not only make inventions to help Johnny, but also to galvanize hunky boys like Gil Nexdor, whom they have a crush on.
- They are also sagaciously and precociously clever, as seen in numerous episodes, including one where they intend to teach Johnny and Dukey a lesson for messing with their experiments.
- Out of all the other character designs in the Netflix reboot, their designs are the most adorable looking.
Why Susan Rocks
- She is the toughest of the two and is not afraid to point out the wrongs in a constructive manner.
- She became famous among most of the young boys.
- Her voice sounds adorably cute like most of the very cute tomboys, all thanks to Maryke Hendrikse.
- Her relationship with Johnny and Dukey is decent.
- Her most iconic outfit and design is 100% tomboy-esque.
- Like her younger brother, Johnny, she always enjoys rock music (rather she's playing her electric guitar with Johnny and Dukey), fighting, skateboarding and playing video games.
- She can be quite unintentionally sympathetic since she gets harrased by Bling-Bling Boy and easily annoyed by Johnny and Dukey.
- She can be fair-minded and correct at many times.
- She is always aware of when Johnny is about to screw up with her and Mary's inventions.
Why Mary Rocks
- She appears to be more girly, level-headed and empathetic than Susan.
- She aproaches and speaks to Johnny in a nicer way.
- All three of her voice actresses, despite not being good as each other, did a great performance for her.
- Unlike Susan, she was interested in girly hobbies, but hates boyish hobbies.
- She is shown to care about Johnny and is more compassionate to him more than anyone else (unless Susan makes an accurate point).
- She is also shown to help Johnny along with Susan when it comes to protecting him on his journeys.
- She is also shown to abominate Bling-Bling Boy (Eugene Hamilton) when he flirts with Susan.
NOTE: Do not imply that they are rip-offs of Dexter from Dexter's Laboratory since both characters are nothing alike. Anyone who does this will be dealt with.
- As the series went on, they became completely flanderized into becoming generic teens who are always alluring with boys they find hunky like Gil (who is their favorite victim).
- Half of the time they manage to get away with DNA experiments or other prohibited experiments. Especially making Dukey talk. This is mainly focused on experimenting with Johnny, altering his DNA as well; they usually don't get caught, leading to them fitting in the Karma Houdini trope.
- They once turned themselves into babies just to spend time with Gil who was doing a babysitting service, which is pedophilia since to dating or falling in love with a baby is illegal.
Susan's Bad Qualities
- Even though Susan can be reasonably correct at times, she intends to get easily stern, rude, harsh, explosive, and mean. This is because she has a bit of a bigger temper compared to Mary, who is less harsher than her.
- It is heavily implied Susan inherited this from Lila Test, the mother of the twins and Johnny.
- She even yelled at Johnny in the Netflix reboot when Johnny said, "Nice sister". Seriously, Susan?
- In "Johnny's Amazing Cookie Company", she once snapped at a girl from a Girl Improvement League and bashed at her, making the girl cry, much to Mary's disgust. Thankfully, she received full comeuppance in the part where she and Mary made a fortune cookie that allowed Gil to kiss a girl holding a sign with his name on it, only for that same girl to come holding her Girl Improvement League sign, which ended up spelling "G.I.L." due to abbreviating the League's name, and have Gil kiss her much to each of their disappointment, despite one of the two deserved it.
- She could be pondered a Butt-Monkey prior to her getting harassed by Bling-Bling Boy at times, whenever her and Mary's inventions go wrong, getting easily bugged by Johnny, and also being a victim of her father's over-the-top punishments alongside the meatloaf gag.
- Like Johnny and Dukey, Susan was always being interested of being gassy, especially farting.
Mary's Bad Qualities
- She doesn’t have as much speaking lines as Susan, which can make her pretty bland.
- Like her sister, she can also be pretty mean to Johnny for stupid reasons.
- Her casting is all over the place, as her voice actress went from Brittany Wilson in season 1, to Ashleigh Ball in seasons 2-4, then Brittany Wilson reprising her role in season 5 and then Ashleigh Ball reprised her role in season 6 and finally Emily Tennant replacing both of them in the reboot.
- Although Mary isn't as tough and stern as Susan, she indeed does have a mean side when she gets angry at Johnny for ruining her and Susan's experiments.
- And when she does get tough, it sounds frightening.
- Mary's voice actress, Britney Wilson, was only there for seasons 1 and 5 while Ashleigh Ball voiced her for seasons 2, 3, 4, and 6.
- The Test Twins are probably the reason why Johnny Test was accused of being a rip-off of Dexter's Laboratory because they are redheaded geniuses who have their own lab where they make lots of cool inventions while an annoying sibling comes and messes them up.