diff --git a/opm/core/tof/AnisotropicEikonal.cpp b/opm/core/tof/AnisotropicEikonal.cpp
index 9a3e278a7..d1eecc10f 100644
--- a/opm/core/tof/AnisotropicEikonal.cpp
+++ b/opm/core/tof/AnisotropicEikonal.cpp
@@ -29,7 +29,11 @@ namespace Opm
     AnisotropicEikonal2d::AnisotropicEikonal2d(const UnstructuredGrid& grid)
 	: grid_(grid)
     {
+	if (grid.dimensions != 2) {
+	    OPM_THROW(std::logic_error, "Grid for AnisotropicEikonal2d must be 2d.");
+	}
 	cell_neighbours_ = vertexNeighbours(grid);
+	orderCounterClockwise(grid, cell_neighbours_);
     }
 
     /// Solve the eikonal equation.
diff --git a/tests/test_anisotropiceikonal.cpp b/tests/test_anisotropiceikonal.cpp
index 68f6f7a9a..38ca9e573 100644
--- a/tests/test_anisotropiceikonal.cpp
+++ b/tests/test_anisotropiceikonal.cpp
@@ -29,6 +29,7 @@
 
 #include <opm/core/tof/AnisotropicEikonal.hpp>
 #include <opm/core/grid/GridManager.hpp>
+#include <cmath>
 
 using namespace Opm;
 
@@ -36,10 +37,17 @@ BOOST_AUTO_TEST_CASE(cartesian_2d)
 {
     const GridManager gm(2, 2);
     const UnstructuredGrid& grid = *gm.c_grid();
-}
+    AnisotropicEikonal2d ae(grid);
 
-BOOST_AUTO_TEST_CASE(cartesian_3d)
-{
-    const GridManager gm(3, 2, 2);
-    const UnstructuredGrid& grid = *gm.c_grid();
+    const std::vector<double> metric = {
+	1, 0, 0, 1,
+	1, 0, 0, 1,
+	1, 0, 0, 1
+    };
+    const std::vector<int> start = { 0 };
+    std::vector<double> sol;
+    ae.solve(metric.data(), start, sol);
+    BOOST_REQUIRE(!sol.empty());
+    std::vector<double> truth = { 0, 1, 1, std::sqrt(2) };
+    BOOST_CHECK_EQUAL_COLLECTIONS(sol.begin(), sol.end(), truth.begin(), truth.end());
 }