To run a Day's solution go to the root dir of the project, open the file in the cabal repl and run its part1 or part2 method.
To run the tests: cabal test, or start the repl with cabal repl all_tests.
Note: cabal test will write all test output in its log file.
To see test results immediately, run cabal test --test-show-details=streaming
Build and run a fresh executable:
cabal clean
cabal configure
cabal build
cabal run aoc2019
This will build an executable that calls whatever is defined in Main.hs
Build and run the test suite, in case you wouldn't want to use cabal test:
cabal clean
cabal configure --enable-tests
cabal build all_tests
cabal run all_tests