Add Hydra jobset and Buildkite pipeline

Author: rvl

.buildkite/pipeline.yml

@@ -0,0 +1,9 @@
+env:
+  NIX_PATH: "channel:nixos-18.09"
+  NIX_BUILD_ARGS: "--cores 0 --max-jobs 2"
+
+steps:
+  - label: 'Run tests'
+    command: ./test/tests.sh
+    agents:
+      system: x86_64-linux

release.nix

@@ -0,0 +1,7 @@
+with (import ./default.nix {});
+
+{
+  inherit nix-tools;
+
+  tests = callPackage ./test {};
+}

test/default.nix

@@ -1,12 +1,10 @@
-{ pkgs ? import <nixpkgs> { } }:
+{ pkgs ? import <nixpkgs> { }
+, haskell ? pkgs.callPackage ../. { }
+}:
 
 with pkgs;
 
 let
-
-  # The new Haskell infra applied to nix representation of Hackage
-  haskell = pkgs.callPackage ../. { };
-
   util = callPackage ./util.nix {};
 
 in {