Merge branch 'split_unittests' into 'master'

Split unittests into seperate files

Split unittests to avoid huge compile unit

See merge request !1
6 jobs for master
Status Name Job ID Coverage
  Test
passed clang-c++11 #1086
Linux

00:02:27

passed clang-c++98 #1088
Linux

00:01:42

passed gcc-c++11 #1085
Linux

00:02:46

passed gcc-c++98 #1087
Linux

00:02:13

passed macos-c++11 #1089
Apple

00:01:15

passed macos-c++98 #1090
Apple

00:01:13