Need help with trompeloeil?
Click the “chat” button below for chat support from the developer who created it, or find similar developers for support.

About the developer

603 Stars 66 Forks Boost Software License 1.0 1.2K Commits 39 Opened issues


Header only C++14 mocking framework

Services available


Need anything else?

Contributors list


trompeloeil logo

CI codecov

Get: Conan

trompe l'oeil noun (Concise Encyclopedia) Style of representation in which a painted object is intended to deceive the viewer into believing it is the object itself...

What is it?

A thread-safe header-only mocking framework for C++11/14 using the Boost Software License 1.0


Also, follow up with the post on sequencing for examples on how to restrict or relax allowed sequences of matching calls.



class Interface { public: virtual ~Interface() = default; virtual bool foo(int, std::string& s) = 0; virtual bool bar(int) = 0; virtual bool bar(std::string) = 0; };

void interface_func(Interface*); // function to test

class Mock : public Interface { public: MAKE_MOCK2(foo, bool(int, std::string&),override); MAKE_MOCK1(bar, bool(int),override); MAKE_MOCK1(bar, bool(std::string),override); MAKE_MOCK0(baz, void()); // not from Interface };

TEST(exercise_interface_func) { using trompeloeil::_; // wild card for matching any value using trompeloeil::gt; // greater-than match

Mock m;

trompeloeil::sequence seq1, seq2; // control order of matching calls

int local_var = 0;

REQUIRE_CALL(m, bar(ANY(int))) // expect call to .LR_SIDE_EFFECT(local_var = _1) // set captured variable to value of param .RETURN(_1 > 0) // return value depending on param value .IN_SEQUENCE(seq1) // must be first match for seq1 .TIMES(AT_LEAST(1)); // can be called several times

FORBID_CALL(m, bar(0)); // but is not allowed

REQUIRE_CALL(m, bar("word")) // expect one call to .RETURN(true) .IN_SEQUENCE(seq2); // must be first match for seq2

REQUIRE_CALL(m, foo(gt(2), _)) // expect call to foo(int,std::string&) .WITH(_2 == "") // with int > 2 and empty string .IN_SEQUENCE(seq1, seq2) // last for both seq1 and seq2 .SIDE_EFFECT(_2 = "cat") // and set param string to "cat" .RETURN(true);


// all the above expectations must be fulfilled here } </trompeloeil.hpp>

How to contribute

Contributions are most welcome. For new functionality, please file an issue as an enhancement request first, to get a discussion going about how to best implement it. Also for bugfixes, it is good to file an issue, so that others can see what the problem is and when it's solved. Internal changes are normally not mentioned in the ChangeLog - it should typically reflect what a user can see (however, performance improvements and silencing warnings are visible for users.) Feel free to add your name to the copyright blurb.

|Change | PR to | |-----------------------------|----------------| |Documentation |master branch | |Trivial bugfixes |master branch | |Non trivial bugfixes |develop branch | |Simple new functionality |develop branch | |Non-trivial new functionality|new topic branch|

Compiler compatibility

Trompeloeil is known to work with:

  • GCC 4.8.4+, 4.9.3+, 5, 6, 7, 8, 9, 10, 11
  • Clang 3.5, 3.6, 3.7, 3.8, 3.9, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
  • Visual Studio 2015, 2017, 2019

Latest patch level releases are assumed in the versions listed above.

Further details on C++11 support, platform and library limitations, may be found in

External Tools


| | | |--|--| | Mocking Modern C++ with Trompeloeil| Mocking Modern C++ with Trompeloeil, introduction to Trompeloeil by Björn Fahller from from from Stockholm C++ UG (34m)| (Slides) | | Using Trompeloeil, a Mocking Framework for Modern C++| Using Trompeloeil, a Mocking Framework for Modern C++, by Björn Fahller from NDC{Oslo} 2017 (52m) (Slides) | | Using Trompeloeil, a Mocking Framework for Modern C++ | Using Trompeloeil, a Mocking Framework for Modern C++, Detailed presentation by Björn Fahller from ACCU 2017 (1h25m) (Slides with extra material) | | Packporting to the future | Backporting to the Future, Detailing the C++11 API and how it came to be, by Andrew Paxie from Pacific++ 2018 (53m) (Slides) |

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.