@BenjaminRodenberg I am not very keen on this addition for some reasons:

• Boost.Test already compares floating point numbers using a tolerance
• The predicate doesn't show where the ranges differ
• The predicate doesn't implement a "real" predicate
• The predicate only needs one template parameter. Comparing std::vector<double> to std::vector<int> is a mistake in the test.
• There is already a build-in tool for this:

   BOOST_TEST(a == b, boost::test_tools::per_element() );

@BenjaminRodenberg I am not very keen on this addition for some reasons:

* Boost.Test already compares floating point numbers using [a tolerance](https://github.com/precice/precice/blob/cff1b7fff5b8c80e62a0e6c3404e4c045577cb4e/src/testing/main.cpp#L96)

* The predicate doesn't show where the ranges differ

* The predicate doesn't implement a ["real" predicate](https://www.boost.org/doc/libs/1_65_1/libs/test/doc/html/boost_test/testing_tools/custom_predicates.html)

* The predicate only needs one template parameter. Comparing `std::vector<double>` to `std::vector<int>` is a mistake in the test.

* There is already a [build-in tool](https://www.boost.org/doc/libs/1_65_1/libs/test/doc/html/boost_test/testing_tools/extended_comparison/collections.html) for this:
  ```c++
   BOOST_TEST(a == b, boost::test_tools::per_element() );
  ```

@fsimonis can you open an issue? I fear otherwise these comments might get lost.