Fix CI to check that generation script has run (#145)

… based on the discussion in #138

CI wasn't checking that the `./scripts/generate.sh` script had been
run, which this change fixes

nix/nixpkgs.nix

@@ -88,7 +88,7 @@ let
               in
                 ''echo './${inputFile} → ./${outputFile}'
                   ${pkgsNew.dhall-json}/bin/dhall-to-yaml --file $out/${inputFile} > $out/${outputFile}
-              '';
+                '';
 
         in
           pkgsNew.runCommand "package-${drv.name}" { XDG_CACHE_HOME="."; } ''
@@ -106,15 +106,40 @@ let
                 outputFile = "README.md";
 
               in
-                pkgsNew.lib.optionalString (version == preferredVersion)
-                ''echo './${inputFile} → ./${outputFile}'
-                  ${pkgsNew.dhall}/bin/dhall text --file $out/${inputFile} | ${pkgsNew.gnused}/bin/sed 's_\.\./package.dhall_https://raw.githubusercontent.com/dhall-lang/dhall-kubernetes/master/package.dhall_g' > $out/${outputFile}
-                ''
+                if (version == preferredVersion)
+                then
+                  ''echo './${inputFile} → ./${outputFile}'
+
+                    ${pkgsNew.dhall}/bin/dhall text --file $out/${inputFile} | ${pkgsNew.gnused}/bin/sed 's_\.\./package.dhall_https://raw.githubusercontent.com/dhall-lang/dhall-kubernetes/master/package.dhall_g' > $out/${outputFile}
+                  ''
+                else
+                  ''
+                    ${pkgsNew.coreutils}/bin/rm --recursive $out/examples
+                  ''
             }
+            ${pkgsNew.coreutils}/bin/rm --recursive $out/docs
           '';
 
     dhall-kubernetes = pkgsNew.callPackage ./dhall-kubernetes.nix {};
 
+    dhall-kubernetes-tests =
+      let
+        process = version: derivation: {
+          name = "${version}-test";
+          value =
+            pkgsNew.runCommand "test-dhall-kubernetes-${version}" {} ''
+              ${pkgsNew.rsync}/bin/rsync --archive ${derivation}/ ./${version}.expected
+              ${pkgsNew.rsync}/bin/rsync --archive ${../. + "/${version}"}/ ./${version}.actual
+
+              ${pkgsNew.diffutils}/bin/diff --recursive ./${version}.{actual,expected}
+
+              touch $out
+            '';
+        };
+
+      in
+        pkgsNew.lib.mapAttrs' process pkgsNew.dhall-kubernetes;
+
     haskellPackages = pkgsOld.haskellPackages.override (old: {
         overrides =
            let

release.nix

@@ -12,7 +12,9 @@ let
     # master in).
     rev = pkgs.runCommand "rev" {} ''echo "${src.rev}" > $out'';
   } // builtins.removeAttrs pkgs.dhall-kubernetes
-         [ "override" "overrideDerivation" ];
+         [ "override" "overrideDerivation" ]
+    // builtins.removeAttrs pkgs.dhall-kubernetes-tests
+         [ "override-test" "overrideDerivation-test" ];
 
   dhall-kubernetes = pkgs.releaseTools.aggregate {
     name = "dhall-kubernetes-aggregate";