Fuzzer

Do not crash when your server lies

What is that?

We all know that the API has a specification. We all write tests to cover “happy paths” and to cover “unhappy paths” when work with the API.

It may seem that we’re pretty safe if we have tests and follow the specification. Well, actually no. Usually it works well in theory, but doesn’t really work in practice.

We can write as many tests as we need to cover all edge cases, but that is both time consuming and error prone. The best choice would be is to automate this process.

from Crash-free code with Fuzzer

Example

- (void)test {
  NSDictionary *sample = @{
    @“name” : @“John Doe”,
    @“age” : @42
  };

  UserDeserializer *deserializer = [UserDeserializer new];

  FZRRunner *runner = [FZRRunner runnerWithBuiltinMutationsForSample:sample];

  NSArray *reports = [runner enumerateMutantsUsingBlock:^(NSDictionary *mutant) {
    [deserializer deserializeUser:mutant];
  }];

  XCTAssertEqual(reports.count, 0);
}

Installation

Components (used by maintainers)

Get the latest component .make file for Fuzzer.

CocoaPods

pod 'Fuzzer', '0.3.0'

Carthage

Pull requests are more than welcome!

Out of the box

Builtin Mutations

Delete Node Mutation

Removes random key/value pair from a dictionary

Replace Node Mutation

Takes random key from dictionary and replaces its value with a value provided by Node Replacement

Builtin Replacements

integer replacement: replaces value with 'random' integer
float replacement: replaces value with 'random' float
string replacement: replaces value with 'random' string
boolean replacement: replaces value with 'random' boolean
array replacement: replaces value with 'random' array
dictionary replacement: replaces value with 'random' dictionary
null replacement: replaces value with [NSNull null]
nil replacement: replaces value with nil (leads to removing key/value from dictionary)

License

MIT, see LICENSE for details

dodikk/Fuzzer