mirror of https://github.com/catchorg/Catch2.git
41 lines
1.1 KiB
Markdown
41 lines
1.1 KiB
Markdown
|
# Making Types Printable
|
||
|
|
|
||
|
|
Catch is capable of using user defined print functions and overloads.
|
||
|
|
|
||
|
|
## Using ostreams
|
||
|
|
|
||
|
|
By default, catch will attempt to display types using an ostream overload is available.
|
||
|
|
|
||
|
|
```c++
|
||
|
|
std::ostream& operator<<(std::ostream&, MySpecialType const&);
|
||
|
|
```
|
||
|
|
|
||
|
|
## using toString
|
||
|
|
If you don't want your type to work with ostreams, or Catch is unable to find the
|
||
|
|
overload you provide, you may alternatively overload `Catch::toString`. The overload
|
||
|
|
must appear **above** the include of `catch.hpp`. For example, if I want to provide
|
||
|
|
a print functionality for `std::pair<int, char>` in my test, the top of my test file
|
||
|
|
would look like this:
|
||
|
|
|
||
|
|
```c++
|
||
|
|
#include <string>
|
||
|
|
#include <sstream>
|
||
|
|
#include <utility>
|
||
|
|
|
||
|
|
namespace Catch {
|
||
|
|
std::string toString(std::pair<int, char> const p) {
|
||
|
|
std::ostringstream oss;
|
||
|
|
oss << '{' << p.first << ", " << p.second << '}';
|
||
|
|
return oss.str();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#include "catch.hpp"
|
||
|
|
```
|
||
|
|
Note that the former approach is preferred, and the latter is more error-prone
|
||
|
|
due to possible typos when typing `Catch` or `toString`
|
||
|
|
|
||
|
|
## Default output
|
||
|
|
|
||
|
|
If neither of the two conditions has been met, catch will output `{?}` by default.
|