Warning: This is a development version. The latest stable version is Version 7.1.1.
In header: #include <stub/compare_call.hpp>
template <class... Args>
struct compare_call
| compare_call (WithArgs &&… expected) | |
| bool | compare (const arguments< Args… > & actual) const |
This stores a tuple of types that is to, at some point, be compared with a different tuple of arguments.
The basic usage is as follows:
auto expectation = std::make_tuple(5, true, 4.0);
compare_call<int, bool, double> expect(expectation);
auto actual = std::make_tuple(4, true, 4.0);
Now compare our expectation with the actual values:
bool result = expect.compare(actual);
assert(result == false);
The compare_call::compare (…) function uses compare_arguments(…) to compare the elements of the two tuples element-wise using compare_argument(…). In the case above the two tuples contain the same types. So every thing is pretty straight-forward.
However, in some cases we want to customize the comparison of two element. This could be that we simply don’t care about a specific value or we want to use a user-define comparison function.
To support this use-case we allow special values to be used in the comparison tuple. The two tuples can therefore have different types, making the implementation a bit more involved and the reason for the type-erausre implemented in this class.
Lets see how this would work in practice.
Notice how we can pass ignore() as the second argument to our expectation tuple:
auto expectation = std::make_tuple(5, ignore(), 4.0);
compare_call<int, bool, double> expect(expectation);
auto actual = std::make_tuple(5, true, 4.0);
Now compare our expectation with the actual values:
bool result = expect.compare(actual);
assert(result == true);
The reason this works when comparing the two tuples element-wise is that the compare_argument(…) function has an overload that accepts ignore as the second argument. By specializing compare_argument(…) we can extend support for more special values to support custom behaviour.