This should be the proper way.

.travis.yml

@@ -1,41 +1,34 @@
 dist: bionic
 language: c
-os:
-   - linux
-   - osx
 
 addons:
   apt:
     packages:
       - lcov
 
+os:
+  - linux
+  - osx
 compiler:
   - clang
   - gcc
 
-jobs:
+script:
-   include:
-      - stage: "Build"
-        script:
   - mkdir build
   - cd build
   - cmake ..
-          - make
-          - cd ..
-      - stage: "Tests"
-        name: "Unit tests"
-        script:
-          - cd build
   - make test
-          - cd ..
+
+jobs:
+  include:
     - stage: "Coverage"
-        name: "Running coverall coverage"
+      os: linux
+      compiler: clang
       script:
         - mkdir coverage
         - cd coverage
         - cmake .. -DCOVERALLS=ON -DCMAKE_BUILD_TYPE=Debug
         - cmake --build .
-          - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then cmake --build . --target coveralls; fi
+        - cmake --build . --target coveralls
- 
+      after_success:
-after_success:
         - bash <(curl -s https://codecov.io/bash)