tensortest: Test more methods

[[Imported from SVN: r12948]]

dune/fufem/test/tensortest.cc

@@ -19,19 +19,36 @@ main()
   e1(1,0) = 4;
   e1(2,0) = 5;
   e1(2,1) = 6;
+  assert(std::abs(e1.trace() - 6.0) < 1e-10);
 
   SymmetricTensor<3> e2;
-  e2(0,0) = 1;
-  e2(1,1) = 2;
-  e2(2,2) = 3;
-  e2(0,1) = 4;
-  e2(0,2) = 5;
-  e2(1,2) = 6;
-
+  e2 = e1;
 
   assert(  e1 == e2);
   assert(!(e1 != e2));
 
+  assert(std::abs(e2(0,0) - 1) < 1e-10);
+  assert(std::abs(e2(1,1) - 2) < 1e-10);
+  assert(std::abs(e2(2,2) - 3) < 1e-10);
+  assert(std::abs(e2(0,1) - 4) < 1e-10);
+  assert(std::abs(e2(0,2) - 5) < 1e-10);
+  assert(std::abs(e2(1,2) - 6) < 1e-10);
+
+  e2.addToDiag(1);
+  assert(std::abs(e2(0,0) - 2) < 1e-10);
+  assert(std::abs(e2(1,1) - 3) < 1e-10);
+  assert(std::abs(e2(2,2) - 4) < 1e-10);
+  assert(std::abs(e2(0,1) - 4) < 1e-10);
+  assert(std::abs(e2(0,2) - 5) < 1e-10);
+  assert(std::abs(e2(1,2) - 6) < 1e-10);
+
+  e2.setDiag(1);
+  e2(1,1) += 1.0;
+  e2(2,2) += 2.0;
+  e2(0,1) += 4.0;
+  e2(0,2) += 5.0;
+  e2(1,2) += 6.0;
+
   e2 *= 2;
   assert(std::abs(e1 * e2 - 2 * (e1 * e1)) < 1e-10);