human: Explain to me the difference between Property Based Testing, Model Based Testing and Fuzzing.

assistant: Property Based Testing, Model Based Testing, and Fuzzing are all techniques used in software testing to ensure the reliability and correctness of software programs. While they share some similarities in their goals, their approaches and methodologies differ. Here is a brief overview of each technique:

1. Property Based Testing:
Property Based Testing (PBT) is a testing approach that involves generating random test inputs based on predefined properties or invariants that the software must satisfy. Instead of writing individual test cases with specific inputs and expected outputs, PBT focuses on testing the overall behavior of a function or system. Testers define properties that the system should adhere to, and the testing framework generates a large number of test cases based on those properties. This allows the discovery of edge cases and unexpected behaviors that might not be found with traditional test cases.

2. Model Based Testing:
Model Based Testing (MBT) is a technique where a model of the system under test is created to represent its behavior, functionality, or requirements. This model is used to automatically generate test cases, test inputs, and expected outputs. The model can be represented using various formalisms, such as state machines, flowcharts, or decision tables. MBT focuses on deriving test cases from the model to ensure that the implementation conforms to the specified behavior. This approach helps in identifying discrepancies between the model and the implementation, which in turn helps in uncovering defects in the system.

3. Fuzzing:
Fuzzing, also known as fuzz testing, is a technique where random or semi-random inputs are generated and fed into the system to test its robustness, security, and stability. Fuzzing aims to uncover vulnerabilities, crashes, or unexpected behaviors that may occur due to invalid or unexpected input data. The primary goal of fuzzing is to stress-test the system and identify potential issues that could be exploited by an attacker or lead to system instability. Fuzzing can be performed using various strategies, including random input generation, mutation-based fuzzing (modifying existing inputs), and generation-based fuzzing (creating inputs based on a predefined grammar or specification).

In summary, Property Based Testing focuses on testing properties or invariants that a system must satisfy, Model Based Testing uses a model of the system to generate test cases, and Fuzzing aims to find vulnerabilities and issues by providing random or semi-random inputs to the system. All three approaches are valuable in different contexts and can be used together to ensure comprehensive testing of a software program.

human: Your answer is too lengthy. All I asked for is the difference between them.

assistant: You're right, apologies.

Property based testing is mainly focused around testing invariants. It's often used to test pure functions, algorithms, or closed systems to ensure correctness.

Model based testing can include property based testing, but more is a bit more general in scope. In model based testing, the goal is to construct a, possibly simplified or partial, model of a complex system, which is then used to construct test cases.

Fuzzing, in contrast, is a general testing technique that amounts to evaluate a system's stability when it is given incorrect, invalid, or unexpected data. One could use fuzzing as a technique in other larger testing strategies, like property based testing.

Keep in mind all of these terms are somewhat vague and there is no single definition that unifies any particular testing strategy.