Unit testing for def/ module.

Added unit tests to test code in def/ module.

.gitlab-ci.yml

@@ -13,6 +13,15 @@ before_script:
   - cd /elektron
   - go mod download
 
+unit_tests:
+  script:
+    - go test ./...
+
+code_coverage:
+  script:
+    - go test --cover ./...
+
 build:
   script:
+    - go build -mod vendor -o elektron-from-vendor ## Testing build from vendored dependencies.
     - go build -v -o elektron