CI: Run ctest tests in parallel, in random order

.travis.yml

@@ -20,4 +20,4 @@ install:
   - cmake --build . --config Release --target install
 
 script:
-  - cmake --build . --config Release --target RUN_TESTS
+  - ctest -C Release -j4 --schedule-random --output-on-failure

appveyor.yml

@@ -54,5 +54,5 @@ build_script:
 after_build:
 - ps: >-
     if ($env:GENERATOR) {
-      cmake --build . --config $env:CONFIGURATION --target RUN_TESTS
+      ctest -C $env:CONFIGURATION -j4 --schedule-random --output-on-failure
     }

circle.yml

@@ -41,7 +41,7 @@ jobs:
           command: cmake --build ~/build
       - run:
           name: "Test"
-          command: cmake --build ~/build --target test
+          command: cmake --build ~/build --target test -- ARGS="-j4 --schedule-random --output-on-failure"
       - run:
           name: "Install"
           command: cmake --build ~/build --target install