after many attempts, I didn't figure how I can run unit tests by terminal with a project that is inside a workspace. I tried to create a new Scheme and run that script which builds but doesn't run any tests:
export DEVELOPER_DIR=/Applications/Xcode.app/Contents/Developer/
xcodebuild -workspace MyProject.xcworkspace\
-scheme MyProjectLogicTests\
-sdk iphonesimulator\
-configuration Debug\
ONLY_ACTIVE_ARCH=NO\
TEST_AFTER_BUILD=YES\
RUN_APPLICATION_TESTS_WITH_IOS_SIM=YES\
clean build