Add backpack test

test/backpack/cabal.project

@@ -0,0 +1,13 @@
+allow-newer:
+  , unpacked-containers:*
+  , unpacked-unordered-containers:*
+
+source-repository-package
+  type: git
+  location: https://github.com/ekmett/unpacked-containers
+  tag: 7dc56993a57511b58257b5d389473e638a7082d2
+  --sha256: 1vijp2hs9ynfm8k2yrv06ccpfi1n2s2b5bqvzrjdd3gqn4bi66q4
+  subdir:
+    unpacked-containers
+    unpacked-unordered-containers
+

test/backpack/default.nix

@@ -0,0 +1,62 @@
+{ stdenv
+, lib
+, fetchFromGitHub
+, cabalProject'
+, haskellLib
+, recurseIntoAttrs
+, compiler-nix-name
+, evalPackages
+, ...
+}:
+
+
+let
+  project = cabalProject' {
+    inherit compiler-nix-name evalPackages;
+    src = fetchFromGitHub {
+      owner = "ekmett";
+      repo = "unpacked-containers";
+      rev = "7dc56993a57511b58257b5d389473e638a7082d2";
+      hash = "sha256-BBsTF7H4jdZk/huvsoQWNkR3GTNgZy8mqs76pKG4Mu4=";
+    };
+    cabalProjectLocal = ''
+      allow-newer:
+        , unpacked-containers:*
+        , unpacked-unordered-containers:*
+    '';
+
+  };
+
+  packages = haskellLib.selectProjectPackages project.hsPkgs;
+  components = lib.concatMap haskellLib.getAllComponents (lib.attrValues packages);
+
+in
+recurseIntoAttrs {
+  ifdInputs = {
+    plan-nix = lib.addMetaAttrs
+      {
+        platforms = lib.platforms.all;
+        # Making this work for cross compilers will be difficult.
+        disabled = stdenv.buildPlatform != stdenv.hostPlatform;
+      }
+      project.plan-nix;
+  };
+
+  run = stdenv.mkDerivation {
+    name = "backpack-test";
+
+    buildCommand = ''
+      printf ${lib.concatStringsSep " " components}
+      touch $out
+    '';
+
+    meta = {
+      platforms = lib.platforms.all;
+    };
+
+    passthru = {
+      # Used for debugging with nix repl
+      inherit project packages;
+    };
+  };
+}

test/default.nix

@@ -178,6 +178,7 @@ let
 
   # All tests.
   allTests = {
+    backpack = callTest ./backpack { };
     cabal-simple = callTest ./cabal-simple { inherit util; };
     cabal-simple-debug = callTest ./cabal-simple-debug { inherit util; };
     cabal-simple-prof = callTest ./cabal-simple-prof { inherit util; };