Compare Eigen matrices in Google Test or Google Mock

Question

I was wondering if there is a good way to test two Eigen matrices for approximate equality using Google Test, or Google Mock.

Take the following test-case as a

Answer 1

EXPECT_PRED2 from GoogleTest can be used for this.

Under C++11 using a lambda works fine but looks unseemly:

  ASSERT_PRED2([](const MatrixXf &lhs, const MatrixXf &rhs) {
                  return lhs.isApprox(rhs, 1e-4);
               },
               C_expect, C_actual);

If that fails, you get a print-out of the input arguments.

Instead of using a lambda, a normal predicate function can be defined like this:

bool MatrixEquality(const MatrixXf &lhs, const MatrixXf &rhs) {
  return lhs.isApprox(rhs, 1e-4);
}

TEST(Eigen, MatrixMultiplication) {
  ...

  ASSERT_PRED2(MatrixEquality, C_expected, C_actual);
}

The later version also works on pre-C++11.