## Mix Assertion, Logging, Unit Testing and Fuzzing with ZeroErr Build Safer Modern C++ Application Speaker: Xiaofan Sun Date: Sep 19, 2024 ## Self-Introduction • Got my Ph.D. from UC, Riverside last T&&... args) ## Printing in both Logging & Assertion Logging macro: LOG("Input is: {)", input); Smart assertion in user code / unit testing also needs pretty printing, e.g.: of Integration • Fuzzing test case can use all those features • Fuzzing do not need additional assertion implementation - Writing fuzzing test case as well as unit test case so that they can share code

@enduml  ### 25.16 Assertion [!assert] You can put assertions in your diagram. @startuml Alice -> Bob : Hello !assert % Bob : Hello !assert %strpos("abcdef", "cd")==3 : "This always fails" Assertion error : This always fails ### 25.17 Building custom library [!import, !include] It’s possible .... 367 25.14 Logging [!log] ..... 368 25.15 Memory dump [!memory_dump] ..... 368 25.16 Assertion [!assert] ..... 369 25.17 Building custom library [!import, !include] ..... 369 25.18 Search

@enduml  ### 25.16 Assertion [!assert] You can put assertions in your diagram. @startuml Alice -> Bob : Hello !assert % Bob : Hello !assert %strpos("abcdef", "cd")==3 : "This always fails" Assertion error : This always fails ### 25.17 Building custom library [!import, !include] It’s possible .... 350 25.14 Logging [!log] ..... 351 25.15 Memory dump [!memory_dump] ..... 351 25.16 Assertion [!assert] ..... 352 25.17 Building custom library [!import, !include] ..... 352 25.18 Search

0) // precondition assertion post (w: w.index() == i); // postcondition assertion ## Proposal: add contract assertions to C++ // precondition assertion // postcondition assertion ## Proposal: add contract pre (i > 0) // precondition assertion post (w: w.index() == i) // postcondition assertion { auto* db = getDatabase(); contract_assert (db != nullptr); // assertion statement return db->retrieveWidget(i); specifying three kinds of contract assertions: precondition assertions, postcondition assertions, and assertion statements. In addition, we specify four evaluation semantics for these assertions — one non-checking

"/lib/aarch64-linux-gnu/libthread_db.so.1". a.out: ./test/test-failed-assert.cpp:9: float fact(float): Assertion `x != 0.0' failed. Program received signal SIGABRT, Aborted. ___pthread_kill_implementation "/lib/aarch64-linux-gnu/libthread_db.so.1". a.out: ./test/test-failed-assert.cpp:9: float fact(float): Assertion `x != 0.0' failed. Program received signal SIGABRT, Aborted. ___pthread_kill_implementation "/lib/aarch64-linux-gnu/libthread_db.so.1". a.out: ./test/test-failed-assert.cpp:9: float fact(float): Assertion `x != 0.0' failed. Program received signal SIGABRT, Aborted. ___pthread_kill_implementation

example, an expression may denote a mathematical object like a natural number, a data type, an assertion, or a proof. Lean has a small and carefully written kernel, which serves to check that an expression even (n + m) In each case, the expression has type Prop, indicating that Lean recognizes it as an assertion. Incidentally, of course, we do know that the property of being even n is algorithmically decidable theory is designed to serve as a mathematical foundation, so that any conventional mathematical assertion can be reasonably expressed, and any theorem that can be proved using conventional mathematical

reflections are achieved with type assertions and type-switch control flow code blocks. ## Type assertion There are four kinds of interface-value-involving value conversion cases in Go: 1. convert a non-interface run time, by using a syntax called type assertion. In fact, the syntax also applies to the second kind of conversion in our above list. The form of a type assertion expression is i.T, where i is an interface type, • or an arbitrary interface type. In a type assertion i.T, i is called the asserted value and T is called the asserted type. A type assertion might succeed or fail. - In the case of T being a non-interface

reflections are achieved with type assertions and type-switch control flow code blocks. ## Type assertion There are four kinds of interface-value-involving value conversion cases in Go: 1. convert a non-interface run time, by using a syntax called type assertion. In fact, the syntax also applies to the second kind of conversion in our above list. The form of a type assertion expression is i.T, where i is an interface type, • or an arbitrary interface type. In a type assertion i. (T), i is called the asserted value and T is called the asserted type. A type assertion might succeed or fail. - In the case of T being a

reflections are achieved with type assertions and type-switch control flow code blocks. ## Type assertion There are four kinds of interface-value-involving value conversion cases in Go: 1. convert a non-interface run time, by using a syntax called type assertion. In fact, the syntax also applies to the second kind of conversion in our above list. The form of a type assertion expression is i.T, where i is an interface or an arbitrary interface type. In a type assertion i.( $ \tau $ ), i is called the asserted value and $ \tau $ is called the asserted type. A type assertion might succeed or fail. - In the case of

proving assertions about objects defined in the language of dependent type theory is to layer an assertion language and a proof language on top of the definition language. But there is no reason to multiply reasonable way of building assertions and proofs. Determining that an expression t is a correct proof of assertion p would then simply be a matter of checking that t has type Proof p. Some simplifications are possible Prop, we can interpret p as a type, namely, the type of its proofs. We can then read t : p as the assertion that t is a proof of p. Moreover, once we make this identification, the rules for implication show