writeDirectReferencesToFile: init

pkgs/build-support/trivial-builders/test.nix

@@ -0,0 +1,20 @@
+{ lib, nixosTest, path, writeText, hello, figlet, stdenvNoCC }:
+
+nixosTest {
+  name = "nixpkgs-trivial-builders";
+  nodes.machine = { ... }: {
+    virtualisation.writableStore = true;
+
+    # Test runs without network, so we don't substitute and prepare our deps
+    nix.binaryCaches = lib.mkForce [];
+    environment.etc."pre-built-paths".source = writeText "pre-built-paths" (
+      builtins.toJSON [hello figlet stdenvNoCC]
+    );
+  };
+  testScript = ''
+    machine.succeed("""
+      cd ${lib.cleanSource path}
+      ./pkgs/build-support/trivial-builders/test.sh 2>/dev/console
+    """)
+  '';
+}

pkgs/build-support/trivial-builders/test.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+# -------------------------------------------------------------------------- #
+#
+#                         trivial-builders test
+#
+# -------------------------------------------------------------------------- #
+#
+#  This file can be run independently (quick):
+#
+#      $ pkgs/build-support/trivial-builders/test.sh
+#
+#  or in the build sandbox with a ~20s VM overhead
+#
+#      $ nix-build -A tests.trivial-builders
+#
+# -------------------------------------------------------------------------- #
+
+# strict bash
+set -euo pipefail
+
+# debug
+# set -x
+# PS4='+(${BASH_SOURCE}:${LINENO}): ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'
+
+cd "$(dirname ${BASH_SOURCE[0]})"  # nixpkgs root
+
+testDirectReferences() {
+  expr="$1"
+  diff -U3 \
+    <(sort <$(nix-build --no-out-link --expr "with import ../../.. {}; writeDirectReferencesToFile ($expr)")) \
+    <(nix-store -q --references $(nix-build --no-out-link --expr "with import ../../.. {}; ($expr)") | sort)
+}
+
+testDirectReferences 'hello'
+testDirectReferences 'figlet'
+testDirectReferences 'writeText "hi" "hello"'
+testDirectReferences 'writeText "hi" "hello ${hello}"'
+testDirectReferences 'writeText "hi" "hello ${hello} ${figlet}"'
+
+echo 'OK!'