Test --keep-going

Make sure that when `nix-build` runs with `--keep-going` we don't stop
the build too early

tests/keep-going.nix

@@ -0,0 +1,34 @@
+with import ./config.nix;
+
+rec {
+
+  # Hack to get the scheduler to do what we want: The `good` derivation can
+  # only be built after `delay_good` (which takes a long time to build) while
+  # the others don't have any dependency.
+  # This means that if we build this with parallelism (`-j2`), then we can be
+  # reasonably sure that the failing derivations will be scheduled _before_ the
+  # `good` one (and so we can check that `--keep-going` works fine)
+  delay_good = mkDerivation {
+    name = "delay-good";
+    buildCommand = "sleep 3; touch $out";
+  };
+
+  good = mkDerivation {
+    name = "good";
+    buildCommand = "mkdir $out; echo foo > $out/bar";
+    delay = delay_good;
+  };
+
+  failing = mkDerivation {
+    name = "failing";
+    buildCommand = false;
+  };
+
+  requiresFooSystemFeature = mkDerivation {
+    name = "requires-foo-system-feature";
+    buildCommand = "mkdir $out; echo foo > $out/bar";
+    requiredSystemFeatures = [ "foo" ];
+  };
+
+}
+

tests/keep-going.sh

@@ -0,0 +1,14 @@
+source common.sh
+
+clearStore
+
+# XXX: These invocations of nix-build should always return 100 according to the manpage, but often return 1
+(! nix-build ./keep-going.nix -j2)
+(! nix-build ./keep-going.nix -A good -j0) || \
+    fail "Hello shouldn't have been built because of earlier errors"
+
+clearStore
+
+(! nix-build ./keep-going.nix --keep-going -j2)
+nix-build ./keep-going.nix -A good -j0 || \
+    fail "Hello should have been built despite the errors because of '--keep-going'"

tests/local.mk

@@ -104,6 +104,7 @@ nix_tests = \
   ssh-relay.sh \
   plugins.sh \
   build.sh \
+  keep-going.sh \
   build-delete.sh \
   output-normalization.sh \
   selfref-gc.sh \