Adds multi GHC travis builds.

.travis.yml

@@ -1,16 +1,59 @@
 language: haskell
-ghc: 7.8
+
+env:
+  - CABALVER=1.18 GHCVER=7.6.3
+  - CABALVER=1.18 GHCVER=7.8.4
+  - CABALVER=1.22 GHCVER=7.10.2
+  - CABALVER=head GHCVER=head
+
+matrix:
+  allow_failures:
+    - env: GHCVER=head
+
 before_install:
-  - "cabal sandbox init"
-  - "cd hask-irc-core"
-  - "cabal sandbox init --sandbox=../.cabal-sandbox"
-  - "cd ../hask-irc-handlers"
-  - "cabal sandbox init --sandbox=../.cabal-sandbox"
-  - "cabal sandbox add-source ../hask-irc-core/"
-  - "cd ../hask-irc-runner"
-  - "cabal sandbox init --sandbox=../.cabal-sandbox"
-  - "cabal sandbox add-source ../hask-irc-core/"
-  - "cabal sandbox add-source ../hask-irc-handlers/"
+  - |
+    if [ $GHCVER = `ghc --numeric-version` ]; then
+      travis/cabal-apt-install --enable-tests $MODE
+      export CABAL=cabal
+    else
+      # Install the GHC we want from hvr's PPA
+      travis_retry sudo add-apt-repository -y ppa:hvr/ghc
+      travis_retry sudo apt-get update
+      travis_retry sudo apt-get install cabal-install-$CABALVER ghc-$GHCVER
+      export CABAL=cabal-$CABALVER
+      export PATH=/opt/ghc/$GHCVER/bin:/opt/cabal/$CABALVER/bin:$PATH
+    fi
+  - $CABAL update
+  - $CABAL sandbox init
+  - cd hask-irc-core
+  - $CABAL sandbox init --sandbox=../.cabal-sandbox
+  - cd ../hask-irc-handlers
+  - $CABAL sandbox init --sandbox=../.cabal-sandbox
+  - $CABAL sandbox add-source ../hask-irc-core/
+  - cd ../hask-irc-runner
+  - $CABAL sandbox init --sandbox=../.cabal-sandbox
+  - $CABAL sandbox add-source ../hask-irc-core/
+  - $CABAL sandbox add-source ../hask-irc-handlers/
+
+install:
+  - $CABAL install --dependencies-only
+
+script:
+  - $CABAL build
+
+  # tests that a source-distribution can be generated
+  - cabal sdist
+
+  # check that the generated source-distribution can be built & installed
+  - export SRC_TGZ=$(cabal info . | awk '{print $2 ".tar.gz";exit}') ;
+    cd dist/;
+    if [ -f "$SRC_TGZ" ]; then
+       cabal install --force-reinstalls "$SRC_TGZ";
+    else
+       echo "expected '$SRC_TGZ' not found";
+       exit 1;
+    fi
+
 notifications:
   email: true
   irc: