Code coverage: exclude SOILWAT2's c code

close #36

.travis.yml

@@ -6,8 +6,11 @@ r:
   - release
   - devel
 sudo: false
-warnings_are_errors: false # set to true: This option forces all WARNINGS from R CMD check to become build failures (default true). This is especially helpful when preparing your package for submission to CRAN
+warnings_are_errors: false # set to true: This option forces all WARNINGS from R CMD check
+  # to become build failures (default true). This is especially helpful when preparing
+  # your package for submission to CRAN
 cache: packages
 after_success:
-  - Rscript -e 'covr::coveralls()'
+  # code coverage but exclude all SOILWAT2 submodule files in scr/
+  - Rscript -e 'covr::coveralls(line_exclusions = as.list(file.path("src", list.files("src", recursive = TRUE))))'