The Cake Is a Lie



""The Enrichment Center is committed to the well being of all participants. Cake and grief counseling will be available at the conclusion of the test.""

- GLaDOS, Portal.

"" ...the virtue of the cake was that it was never to be consumed, neither by you nor by your children after you.""

- John Maynard Keynes, calling out the cake back in 1919

There will be cake at the bottom of this page.

A character, usually an antagonist, promises another character, usually the hero, a reward if they can complete some task for them. This can be anything from fame, to riches, to women, to baked desserts, or pretty much anything generally considered desirable.

But wait! "I Lied." It turns out that there is no reward! Upon either finding this out or completing the task, it's discovered that the villain simply wanted something to be done for them, and now plans to dispose of the hero now that their usefulness to the villain has ended.

Often a crucial part of many a MacGuffin Delivery Service. May make use of False Reassurance. Sometimes employed by a Mission Control that is off its meds.

When the other character isn't necessarily evil, doesn't plan on hurting the hero, and simply raises his or her standards whenever the other character comes near to completion, this becomes Moving the Goalposts. Compare Deal with the Devil, Rewarded as a Traitor Deserves, You Said You Would Let Them Go, Released to Elsewhere. Contrast Villains Never Lie.

Only overlaps with I Was Told There Would Be Cake when the reward the villain promises is actually cake.

Anime

 * In Liar Game, during the Contraband game, Yokoya enforced a point-based loyalty scheme to guarantee loyalty from the members of his team that they would spy on the other members and report any dishonesty to him, where he would give more money to the snitch. Fukunaga suspects that Yokoya didn't even keep count; he just wanted the members to feed him as much information of the others as possible.
 * This occurs to Lina Inverse in the first Slayers movie. The character in question isn't evil and doesn't plan on hurting Lina per se, but it's definitely not a case of Moving The Goalposts. Needing Lina to risk her life by going back in time hundreds of years in order to save a much younger version of himself, his love, and a group of elves from a mazoku, the elderly ghost of an adventurer promises Lina to show her the location of "the fountain of growth", which she interprets, and is lead on to believe, will finally make her tall, curvy, and stacked. In reality, the ghost has lied, and the fountain in question is the reverse of the fountain of youth, aging things that touch its waters to death, making Lina's trials and tribulations completely meaningless (in her eyes). However, since Lina was particularly dumb for believing him, and since he's really the ancestor of her (not-yet-encountered-yet-at-the-time) love and life-long partner Gourry, it worked out in her favor anyways.
 * There was a slight instance of this in the Battle City arc of Yu-Gi-Oh!; Arcana, one of Marik's servant's, is promised a reunion with his lost love upon fulfillment of a mission; Marik even put a mannequin shrouded by curtains in the room to persuade him. He fails his mission, and the last thing he sees before Marik kills him is that he never intended to keep his end of the deal.

Comic Books

 * There was a Rugrats comic story where Chuckie had all but one of the collectible Reptar cards, and Angelica claimed she would give him the one he was missing if he performed a series of chores for her. When he finished them all, it turned out the card she gave him was a phony drawing.
 * In the Gunslinger comic, one of the villains ask an addict for information on the heroes, implying that they will give him "metal" in exchange. After they are finished, the addict asks if he is getting gold or silver, the villain replies 'lead' and shoots him. (This is a visual re-telling of the incident from the original source, the novel Wizard and Glass.)
 * In Power Girl (Issue #12 to be exact), super-villainess Satanna wants Mad Scientist Dr. Sivana to make her a super-weapon to kill Power Girl (Kryptonians being rather hard to kill). Sivana wants some bouncy-bouncy in exchange. Despite her disgust, Satanna complies, and afterwards Sivana points out that they are both "bad guys," and as long as he got his, he doesn't care that she doesn't get anything. So not only has she debased herself for nothing, he adds injury to insult by making his robots beat her up and throw her out of a fourth-story window. So not only is Sivana a complete pig, he's made Satanna's list—he'll be showing up in revenge-oriented tropes in the near future.
 * The obscure French comic book "38e parallèle" features the story of the French expeditionary force in The Korean War. An officer promises his commando a treasure behind the enemy lines; it was actually an undercover operation seeking a Vietcong agent.
 * Subverted in one Marvel comic. A skrull promises a human 'the most beautiful woman in the galaxy' to betray his species. He accepts, but then turns back when somebody points out to him 'Even if the Skrull was going to keep his promise, what's beautiful to a reptilian alien?' - then we see a beautiful Skrull woman waiting to be given away to some lowly human (out of love for the invading skrull). The Fridge Logic is, Skrulls are shapeshifters. He could send the ugliest woman, and she could change into the most beautiful.
 * Subverted in an early issue of The Batman Adventures, the animated Batman spin-off comic from the 1990s. The Joker hijacks a cable television outlet and uses it to broadcast himself onto a closed-circuit TV set delivered to Selina Kyle's apartment. After revealing that he knows Selina is Catwoman, Joker tells her that he has concocted a foolproof plan for stealing the Crown Jewels from the Tower of London, and asks her if she'd like to attempt the feat. Selina, who relishes this ultimate test of her burglary skills, still feels suspicious, even asking Joker, "What's the catch?" Turns out, Joker also wants her to snatch something else for him while she's in London (we're never told exactly what this is, but it's apparently microcircuitry or something similarly electronic). Once Selina has heard all the details, she goes through with Joker's plan - but Batman outsmarts her and manages to prevent her from swiping the jewels, and Catwoman barely escapes capture. She does, however, manage to acquire the technology Joker requested, and sends it to him at the end of the comic. (In the next issue, it's finally revealed that whatever Joker had Catwoman steal for him allows him to override every other TV station in Gotham City, so that he can broadcast his sadistic variety show on every channel.) But even though Catwoman didn't get what she wanted, Joker didn't care: she managed to get him on TV, and whether or not she also got the Crown Jewels was irrelevant.

Fairy Tales

 * In "The Pied Piper of Hamelin", the town offers a handsome reward for ridding them of the rats. When the piper succeeds flawlessly, they flatly refuse to pay him and boot him out of the town. It turns out pretty badly for them.

Film
""You're just a toy, Sebastian. A little toy I like to play with.""
 * In Dangerous Liaisons, when Valmont breaks off his relationship with Madame de Tourvel and comes to collect his "reward" from Merteuil, she simply tells him "no," and mocks him to his face.
 * Therefore, also seen in Cruel Intentions.

""One more thing: I lied". (Women revert to demon form, and lunge)"
 * The Collector does this in Demon Knight, enticing one of the heroes to the evil side with promises that include a bunch of hot dancing women. The Collector congratulates him on his wise choice, and...


 * The Collector does this to everyone who listens to him. Another character agrees to betray the others and removes the barrier keeping the demons at bay in exchange for his own freedom. As he is about to leave, the Collector admits he lied, and the demons tear the guy apart.
 * In Parts the Clonus Horror, the clones are told that they are preparing for a trip to America, which is portrayed like paradise.
 * The Island is based on "The Clonus Horror" and has a similar lie. The clones are told that they are preparing for a trip to "The Island," the only haven from a "virus outbreak."

Literature

 * This is also sometimes known as "jam tomorrow" for the White Queen's promise in Through The Looking Glass to provide "jam every other day"—which turns out to mean jam tomorrow and jam yesterday, but never jam today.
 * Explicitly referenced by Terry Pratchett in Discworld's Hogfather.
 * The White Witch in The Lion, The Witch and the Wardrobe promises Edmund more Turkish Delight for playing along with her.
 * Played with in the Buffy spin-off novel Pretty Maids All In A Row: The novel focuses on Spike and Dru, who are hired by a demon to do a job for him, with the promised reward being a powerful magical artifact Dru has decided she wants. A third of the way through, there's a flashback revealing that this artifact was stolen off the demon sixty years ago—but then two-thirds of the way through, there's another flashback revealing that thirty years ago the demon took it back.
 * In the Philippa Gregory book The Boleyn Inheritance,
 * The Millennium Trilogy plays with this.
 * In Sergey Lukayenko's first published novel Knights Of The Forty Islands, several hundred children are kidnapped and put into an artificial environment consisting of small islands connected by bridges. They are given swords and are told that anyone who conquers all islands gets to go home. The thing is, the captors know full well that Humans Are the Real Monsters and that even children can be turned into monsters given the right conditions, meaning there is no way for any one group to realistically conquer such a large area, and alliances are doomed to fail. Also,.
 * In Sommerset Maugham's story "A Friend in Need", a wealthy businessman tells the narrator about an incident in which he promised a Remittance Man a position at the firm if he could successfully swim a treacherous length of water. The Remittance Man drowned to death, and the business man then casually reveals that he never had a position open in the first place.

Live Action Television

 * Doctor Who: "Yes, I lied, it's a jammy dodger. But I was promised tea!"
 * The premise of the US Office episode "Scott's Tots" was founded on this.
 * It is worth noting that Michael had every intention of sending those kids to college when he made that promise. He was just ridiculously over-optimistic about what his life would be like by the time they would graduate.
 * Burn Notice: Sam is trying to clear out an office temporarily so Michael can steal some information from one of the office computers. So posing as an office manager, he tries to herd everyone into a meeting room to work on "team work activities". It's not until he promises cake do people start listening to him. They're very grouchy later when they find out he lied.
 * Chuck: In "Chuck vs the Wedding Planner" the team sets up an elaborate con Wedding reception, including a cake made of fondant, icing... and Styrofoam.
 * Subverted on Boy Meets World. When Mr. Feeney has trouble getting Shawn to attend his SAT preparation class, he makes up lie on the spot about there being delicious cake at the class. But later we see Shawn at the class, and he is in fact eating a big piece of cake.
 * On Twilight Zone, a talkative man bets another member of his exclusive club a fortune that he can't remain silent for a full year. He succeeds, but the man he made the bet with admits that he's flat broke and could never have paid the agreed-upon sum.
 * The crew on Farscape once visited an agricultural world where tomorrow was always a rest day, but it never came because the workers' memories kept getting re-written as to what day it was.

Music

 * A song written by songwriter Ed Pickford, and popular with many folk singers, is Pound a Week Rise. The workers of the coal mines are fed up and want a raise. When they confront the then chairman of the National Coal Board (Lord Robens), he tells them that he used to be a miner and knows how hard it can be so he makes them a deal. If he can get their output to break records, he'll give raise their pay by a pound per week (hence the title). When they finally accomplish this, he laughs at them, denies them the raise he promised and yells at them to get back to their jobs.
 * The Child Ballad "The Golden Vanity" takes this and puts a rather...dark spin on it..
 * This trope is actually very popular in the traditional songs of many countries.
 * According to That Other Wiki, in the non-Bowdlerized ending to the song "Big Rock Candy Mountain", the candy is a lie.

Tabletop Games

 * In Shadowrun games, this is, way too often, what the "run offered by Mr. Johnson" turns out to be—especially if the Game Master really likes screwing his players over.

Video Games
"Kid: I'm hungry. Mother: There's cake in Oregon. Kid: THAT'S A LIE!"
 * Portal: Trope Namer ("THE CAKE IS A LIE" being written on walls in various places by Doug Rattmann, an employee turned test subject). Note that there was cake, it just wasn't for you.
 * Moreover, note the wording by GlaDOS: "There will be cake" (and similar vague statements, like "cake will be served" and "cake... will be available"). It's not until later (when her lies become more transparent) does GLaDOS suggest that Chell will be the one to eat it ("Okay, the test is over now. You win! Go back to the recovery annex for your cake.")
 * This is later spoofed in Tales of Monkey Island Chapter 4: The Trial and Execution of Guybrush Threepwood,
 * Likewise referenced in the game adaptation of X-Men Origins: Wolverine: in one level, the player can use a portal device to access a hidden room which contains a cake; doing so unlocks the Achievement "The Truth".
 * The iPod game "Highborn" references this by promising that there will be cake at the end of the tutorial. There is none.
 * Referenced in Minecraft—one of the Achievements is to bake a cake, and its name is "The Lie".
 * Which in an odd coincidence, Portal 2 was released at almost the same time of Beta 1.6 (which introduced said achievement, weather and other things). Portal 2 atleast tried to not use the gag except twice in the game.
 * Also referenced in Bookworm Adventures: one of the loading screen messages reads "Lying about cake...".
 * Averted in the fan prequel Portal: Prelude. It should be obvious what the player has to do after this...
 * Also averted in Portal: The Flash Version. However, based on the context of that game, GLaDOS likely wasn't even finished (perhaps even created) at that point.
 * World of Warcraft has an achievement called "The Cake Is Not a Lie," earned by learning the very hard-to-get chocolate cake recipe and baking said cake.
 * Erik Wolpaw, Portal's writer, had announced that there will be absolutely NO cake anywhere in the sequel, not even in the dialogue, because he is tired of cake jokes. However, with the binary code in the following comic translating to "the cake is a lie," and Doug Rattmann's drawing of the cake in the Portal 2 preview, that turned out to be a lie of its own. He even stated they couldn't resist putting one joke—on a door claiming to lead to GLaDOS' emergency shutdown and cake dispensary. Take a guess as to the door's authenticity. Other than that, the Arc Word has turned into "potato".
 * In the Neverwinter Nights mod Tales of Arterra, if you complete the obstacle course in Vannik the Red's hideout you find a large chest containing a sheet of paper: "Congratulations! Your reward is knowledge! Word: bamboozled. Synonyms: hoodwinked, befuddled. Definition: to be deceived. Example: The foolish adventurer was bamboozled into thinking there was loot at the end of the obstacle course!"
 * In Bully, Gary prompts you to follow him through the school's basement, promising nothing specific, just having something to show you.
 * In Morrowind, a woman's ring landed in a pond. She wants it back, and she'll nookie you for it. Except that she just wanted you down at the bottom of a hill so she could rob you from the high ground.
 * Similarly, in Oblivion, a mage offers to recommend you for membership to the Arcane University if you retrieve his magical Ring of Burden from the bottom of a well. Turns out he was just hoping you'd drown while down there.
 * Which is absolutely hilarious, in an Idiot Ball/Fridge Logic manner if you're an Argonian. Argonians can breath underwater.
 * In Baldur's Gate 2, the player is offered a quest with a 10,000 gp reward - big money at that point in the game - by . Once you reach the quest area, however, you're manipulated into.
 * Several other characters do this as well, and  come to mind.
 * By the time of, CHARNAME has apparently become Genre Savvy to this, as (s)he observes in the diary: "As I expected,   attacked me as soon as I released it from its prison..."
 * As a rule of thumb, almost every evil guy who gives you a quest in the Baldur's Gate series will end up fighting you. Which doesn't mean you shouldn't do the quest, since you will find the reward they promised you over their dead body anyway.
 * And valuable loot that's probably more useful than the money.
 * Flonne in Disgaea tells Laharl that she will give him something good if he helps find her pendant. The something good is.
 * In Mario & Luigi: Superstar Saga Prince Peasly says he will give you something of around 99,999,999 Mushroom coins for defeating the Big Bad. In the end,
 * Worse, prior to that you run into the same problem, but even though the exchange rate is bad the first time, it's still good enough that Peasley's bet is a fantastic deal. Meaning that either A) someone is lying, or B) the Mushroom Kingdom's economy crashes every time she gets kidnapped.
 * So, about every two weeks then? There goes that triple-A credit rating...
 * The tutorial in Mercenaries 2 is basically one of these.
 * In the episode The Tomb of Sammun-Mak of Sam and Max, the great-grandpas of Sam and Max (Sameth and Maximus) are entrusted by M. Papierwaite to find and deliver an artifact called The Devil's Toybox. Having done so, they find out the promised reward is
 * Warhammer Online has a quest in which a goblin tells you to run through the PvP zone of a much lower level to look for "shinies". This triggers the in-game mechanic of turning people too high for a given zone into a chicken - and if you actually do make it through alive, the goblin roundly mocks you for believing him. You do get a humorous title for it, though.
 * In The 7th Guest, Stauf promises that the guest who  will have their wish granted. This is not quite what happens...
 * In Red Dead Redemption, this happens twice. First, Later,
 * At the beginning of Tales of Monkey Island Chapter 4, Guybrush thinks there would be "ice cream cake" when Flotsam's citizens arrive.
 * Stranglehold has Mr. Wong sending Tequila after the Golden Kane and the Zakarovs in order to rescue Billie, Tequila's wife and Wong's daughter, and Teko, Tequila's daughter..
 * The deal that  made with the blue people's government in Ghost Trick was that
 * Kingdom Hearts, anyone? It contains a plethora of this trope. Let's see...
 * Hades promises Cloud assistance in exchange for his services, and it turns out he lied. Both in the first game and Chain of Memories.
 * Subverted with Ursula; in the first game she planned on keeping her promise, for once, but she would have done it in a way that mirrored the Jackass Genie trope. In the sequel, she still planned on keeping her promise, but it was more along the lines of Loophole Abuse. It was played straight in the third game.
 * Throughout the first three sections of Haunting Ground.
 * Gamesoft's mobile phone version of Oregon Trail has this exchange between two characters:

Web Original
"Marik: Shut up! What we came here to do is defeat Yugi Muto, once and for all! Bonz: Brains. [I came here for the free tacos.] Marik: By the way, there are no free tacos; that was a lie. Bonz: Brains... [It figures.]"
 * From Yu-Gi-Oh the Abridged Series:

"Duel Robot: Welcome to the Aperture Science Duel Monsters Training Programme. If you win this children's card game, There Will Be Cake. (Some time later, after Kaiba trounces the Duel Robot with Obelisk) Kaiba: The cake is a lie, bitch."
 * From later in the same series: Kaiba is in training, because he actually has to learn how to play Duel Monsters. (Dun, dun, DUN~!)

"Yukari: I'm not falling for that again. Ran: [beat] I made funnel cake. Yukari: ...funnel cake?!"
 * Walfas shorts have this...apparently, the only way to get Yukari out of bed to do anything is to promise her waffles. There are never any waffles.


 * In Suburban Knights, The Nostalgia Critic lured everyone to Chicago under the promise of a free car.

Western Animation
"Kid: Uh, we were to understand there'd be pie and punch? Kyle: There isn't any. Kid: Oh."
 * In Beauty and the Beast: The Enchanted Christmas, Forte promises a musical solo for his henchman Fife in exchange for performing many of the tasks that would help Forte challenge/endanger Belle. Near the end of the movie when Forte gets confronted by Belle, Beast and the gang, Fife finds the pages for his solo to be blank.
 * In Invader Zim, the kids have to sell candy bars to raise money for new desks. Zim goes to great lengths to sell the most in order to win the secret ultimate prize, which turns out to be....
 * ADHESIVE MEDICAL STRIPS
 * Averted quite well in The Marvelous Misadventures of Flapjack, when Peppermint Larry offers K'nuckles and Flapjack 100 pieces of candy for a candy wrapper with a plus/X on it. They get their candy when Flapjack provides a forged wrapper, but the original wrapper was meant to lead Larry to the fabled Candied Island.
 * However, in another episode, a mechanical fortune-telling genie promises to tell K'nuckles and Flapjack the location of Candied Island if they can beat him in a guessing game. He's obviously lying, which was intended, as the genie was meant to be creepy, sadistic, and manipulative. At least, until
 * In an episode of Chowder, the titular character is promised some cake if he goes to a party. When he gets there, there is no cake. He even says, "The cake was a lie!"
 * The tip is, 'Always buy new shoes in the afternoon, after your feet have expanded'.
 * An episode of the Where's Waldo? animated series did the same joke.
 * In an episode of He Man and The Masters of The Universe, Mech-a-neck is tired of just having an extendo-neck as a special ability, and a wizened little man says he can give him better powers if he retrieves a MacGuffin for him. Once he gets the MacGuffin he just runs off and uses it to transform back into a handsome and powerful mage, after being turned into an old man by the Sorceress.
 * In The Emperors New School, Kuzco, Malina and Kronk go on a quest to capture a Shuaka, which is supposed to give them a pot of gold. The Shuaka tells them that in order to get the pot of gold, they'd have to perform a series of tasks. It turned out there was no gold, and he was just getting them to do his chores for him.
 * In South Park: Bigger Longer and Uncut, Cartman suggests bringing in potential members to La Résistance by promising punch and pie. When the meeting starts ...


 * So the kids leave.

"Buzz: So the cake is a lie? Penguin: No, the cake is real, and extremely rich. But you're not really a space ranger at all! You're a toy! Andy's toy!"
 * Again invoked with the kids trying to start a group for protecting films of America with "Free Hat." ... Which gets misconstrued to be a criminal called Hat McLoughley.
 * Subverted in the MAD bit "The Buzz Identity":


 * In one episode of The Simpsons, Homer intentionally gained weight until he became at least 300 lbs. heavy. When Marge decided to tell Homer to stop and Lisa went to tell him Marge was calling, she said Marge baked a cake. After Marge's failed attempt to dissuade Homer, he still asked about the cake.
 * In another episode, Springfield Police Department started a fake boat giveaway to lure lawbreakers. When it was Homer's turn, he was forced to pay fines and still had to be told the boat was a lie.
 * In Dave the Barbarian, Fang tricks Dave into entering a Mongrel Hordes Boot Camp, by saying they were going to a hat show.

Real Life

 * Jack Thompson promised 10,000 dollars to a charity of Take Two Interactive chairman Paul Eibeler's choice if anyone would make a certain video game, then failed to deliver when the game wasn't made once, but multiple times even. Read more on the page about him. Penny Arcade made the donation when he revealed he wouldn't, with the check note saying "Because Jack Thompson wouldn't." Jack Thompson tried to force them to rescind the check, making him try to keep the cake a lie, even if he wasn't the one baking it. That's right, not only did Jack Thompson lie about donating to charity, he tried to stop other people from donating to charity to make up for his dumb ass. You can read all about that story here.
 * In a 1996 ad campaign to promote Pepsi Stuff, commercials for the film True Lies claimed that if anyone collected 7,000,000 points, Pepsi would give that person a Harrier jet (featured in the movie). A man by the name of John Leonard redeemed a check equivalent to the amount of the 7,000,000 points, but Pepsi refused on the grounds that the jet was not really being offered. After a lawsuit was filed, a federal judge sided with Pepsi.
 * Seems Pepsi could have used a lesson from Burma-Shave.
 * Burrell Smith (who designed the hardware for the original Macintosh) would often promise to be your best friend in order to get you to do something. This relationship, however, only lasts a few milliseconds.
 * Happens all too often when you're a toddler. Your parent will promise you a reward if you do something or go through something, and once that's over with they take back their word. This even happens to kids, teenagers, and even adults, and it encourages kids to engage in rebellious behavior—and they wonder why there's so many rebellious teenagers around.
 * As the description for Moving the Goalposts points out, this is actually a subtle form of psychological abuse which may result in life-long trust issues since, well, if you can't trust your parents, whom can you trust?
 * Me.
 * Although the exact amount is disputed Thomas Edison reportedly promised 10-50,000$ (1.1 million today) to anyone who could solve the crippling inefficiencies in his prototype automobile motors and electrical generators. Nikola Tesla solved them both while Edison refused to honor his agreement. Edison told Tesla he had a lot to learn about an American sense of humor—the cruel irony is that Edison still gets the credit for being a genius despite inventing very little of what he's credited with while Tesla, who invented more things than Edison had patents, was all but forgotten (though that's starting to change).
 * Edison also refused to raise Tesla's salary from 18 to 25 dollars a week (a rather reasonable request as the original salary was for a line worker while Tesla was now making some of the most advanced creations at Edison's plant). All of this was the main reason why Tesla went to work for Westinghouse, who not only fully acknowledged him, but also paid him a crap-load of money, which Tesla then immediately spent on various bizarre inventions. That said, Tesla indeed was one of the fathers of a modern AC power grid, and won the "War of Currents" for Westinghouse.


 * Jodee Berry, a former Hooters waitress in Panama City, Florida, won a contest for most beer sales held by her boss, who announced that the grand prize was a new Toyota. On the day of the presentation, she was blindfolded and led to the restaurant's parking lot to receive her prize...which turned out to be a Toy Yoda! She quit immediately and won an undisclosed settlement against Gulf Coast Wings, Hooters parent company, a year later. Part of the settlement included a Toyota car of her choice.
 * Swedish-Finnish journalist, writer and talk-show host Mark Levengood once said this happened to him. His mother told him that if he did not start smoking before his 18th birthday, she would pay for his drivers license. When he turned 18 and asked for his reward, his mother lit another of her cigarettes and told him she had never planned to pay his driving lessons. "The important thing was that you did not start smoking, and it did succeed, didn't it?"
 * A literal, if subverted, example: Twinkies. Read the ingredients list; very little of it sounds even remotely like cake, more like industrial sludge...and yet, like the disgusting ingredients of the infamous Portal cake, it all comes together to form...yup. Cake.
 * Atheists tend to view religious claims of an afterlife as examples of this trope, with heaven as "the cake" (or more precisely "Pie in the Sky" or "Jam Tomorrow"). There is no evidence that the cake exists, and you can't ask anyone who has finished the test. You only have GLaDOS's promise, combined with your own desire for cake.

...I Was Told There Would Be Cake.