Try to get fgl-arbitrary tested again

Author: ivan-m

.travis.yml

@@ -119,6 +119,7 @@ install:
   - cabal new-build -w ${HC} --disable-tests --disable-benchmarks --project-file="cabal.project" --dep -j2 all
   - rm -rf .ghc.environment.* "."/dist
   - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
+  - DISTDIRARB=$(mktemp -d /tmp/dist-test.XXXX)
 
 # Here starts the actual work to be performed for the package under test;
 # any command which exits with a non-zero exit code causes the build to fail.
@@ -149,5 +150,27 @@ script:
   # Build without installed constraints for packages in global-db
   - if $UNCONSTRAINED; then rm -f cabal.project.local; echo cabal new-build -w ${HC} --disable-tests --disable-benchmarks all; else echo "Not building without installed constraints"; fi
 
+  # Check the fgl-arbitrary sub-package
+  - cd fgl-arbitrary
+  # Relying upon fgl being installed above when testing sdist, and that
+  # it doesn't require any other dependencies not used by fgl.
+
+  # test that source-distributions can be generated
+  - cabal new-sdist all
+  - mv dist-newstyle/sdist/*.tar.gz ${DISTDIRARB}/
+  - cd ${DISTDIRARB} || false
+  - find . -maxdepth 1 -name '*.tar.gz' -exec tar -xvf '{}' \;
+  - "printf 'packages: fgl-arbitrary-*/*.cabal\\n' > cabal.project"
+  - touch cabal.project.local
+  - "if ! $NOINSTALLEDCONSTRAINTS; then for pkg in $($HCPKG list --simple-output); do echo $pkg  | grep -vw -- fgl | sed 's/^/constraints: /' | sed 's/-[^-]*$/ installed/' >> cabal.project.local; done; fi"
+  - cat cabal.project || true
+  - cat cabal.project.local || true
+  # this builds all libraries and executables (without tests/benchmarks)
+  - cabal new-build -w ${HC} --disable-tests --disable-benchmarks all
+
+  # build & run tests, build benchmarks
+  - cabal new-build -w ${HC} ${TEST} ${BENCH} all
+  - if [ "x$TEST" = "x--enable-tests" ]; then cabal new-test -w ${HC} ${TEST} ${BENCH} all; fi
+
 # REGENDATA ["--ghc-head","fgl.cabal"]
 # EOF