More sophisticated travis

.travis.yml

@@ -3,16 +3,18 @@ language: bash
 # Use container-based infrastructure for quicker build start-up
 sudo: false
 
-addons:
-  apt:
-    sources:
-    - debian-buster    # Grab shellcheck from the Debian repo (o_O)
-    packages:
-    - shellcheck
-
 # TODO: also run checkbashisms.pl (currently two instances of non-compliance)
 script:
- - shellcheck ghcup.sh
+ - ./ghcup.sh -v install 8.2.2
+ - ./ghcup.sh -v install 8.4.3
+ - ./ghcup.sh -v install 8.6.1
+ - ./ghcup.sh -v set 8.6.1
+ - ./ghcup.sh -v set 8.4.3
+ - wget https://www.haskell.org/cabal/release/cabal-install-2.2.0.0/cabal-install-2.2.0.0-x86_64-unknown-linux.tar.gz
+ - tar -xzf cabal-install-2.2.0.0-x86_64-unknown-linux.tar.gz
+ - ./cabal new-update
+ - ./cabal new-install ShellCheck
+ - ~/.cabal/bin/shellcheck ghcup.sh
 
 matrix:
   fast_finish: true