Skip to content

Latest commit

 

History

History
73 lines (42 loc) · 2.23 KB

assertions.md

File metadata and controls

73 lines (42 loc) · 2.23 KB
Raw

Assertions

There are multiple ways to fail a test case:

  • Returning false
  • Throwing an unrecognized exception
  • Using assertions

Each is equally valid but using RapidCheck's assertions are a convenient way to also provide relevant messages about what failed. Additionally, if to discard tests cases, using the precondition assertions are your only option.

NOTE: The assertion macros are implemented using exceptions. The particular exceptions are an implementation detail but you should ensure your properties are exception safe or be prepared to leak resources.

Capturing

In a lot of cases, RapidCheck can capture the expansion of the expression used in the assertion macros in a way inspired by the Catch.hpp framework. This means you can write your assertions in a style that is natural to C++:

std::string foo = "foo";
std::string bar = "bar";
RC_ASSERT(foo == bar);

If used in a property, RapidCheck might print something similar:

main.cpp:24:
foo == bar

Expands to:
"foo" == "bar"

However, in some cases, this capturing might fail to include the information that you want.

Reference

The selection of assertion macros is currently rather slim. Suggestions on how to improve this is welcome.

RC_ASSERT(expression)

Fails the test case if expression evaluates to false.

RC_ASSERT_FALSE(expression)

Fails the test case if expression evaluates to true. Use this instead of RC_ASSERT(!(...)) since RapidCheck cannot capture the expression in that case.

RC_ASSERT_THROWS(expression)

Fails the test case if expression does not throw an exception.

RC_ASSERT_THROWS_AS(expression, ExceptionType)

Fails the test case if expression does not throw an exception that matches ExceptionType.

RC_FAIL(msg)

Unconditionally fails the test case with msg as message.

RC_SUCCEED_IF(expression)

Causes the test case to immediately succeed if expression evaluates to true.

RC_SUCCEED(msg)

Unconditionally makes the test case succeed with msg as the message.

RC_PRE(expression)

Discards the test case if expression evaluates to false.

RC_DISCARD(msg)

Unconditionally discards the test case with msg as the message.