From 14c001d6133b5dadc16b086ebaf940eb9f6ffe32 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Tue, 26 Aug 2025 21:33:12 +0200
Subject: [PATCH] Add a test for `nix flake check` building checks

---
 tests/functional/flakes/check.sh | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/tests/functional/flakes/check.sh b/tests/functional/flakes/check.sh
index 27e73444a..50a2b21c9 100755
--- a/tests/functional/flakes/check.sh
+++ b/tests/functional/flakes/check.sh
@@ -135,3 +135,35 @@ EOF
 
 checkRes=$(nix flake check --all-systems $flakeDir 2>&1 && fail "nix flake check --all-systems should have failed" || true)
 echo "$checkRes" | grepQuiet "formatter.system-1"
+
+# Test whether `nix flake check` builds checks.
+cat > $flakeDir/flake.nix <<EOF
+{
+  outputs = { self }: {
+    checks.$system.foo = with import ./config.nix; mkDerivation {
+      name = "simple";
+      buildCommand = "mkdir \$out";
+    };
+  };
+}
+EOF
+
+cp "${config_nix}" "$flakeDir/"
+
+expectStderr 0 nix flake check "$flakeDir" | grepQuiet 'running 1 flake check'
+
+cat > $flakeDir/flake.nix <<EOF
+{
+  outputs = { self }: {
+    checks.$system.foo = with import ./config.nix; mkDerivation {
+      name = "simple";
+      buildCommand = "false";
+    };
+  };
+}
+EOF
+
+# FIXME: error code 100 doesn't get propagated from the daemon.
+if !isTestOnNixOS && $NIX_REMOTE != daemon; then
+    expectStderr 100 nix flake check "$flakeDir" | grepQuiet 'builder failed with exit code 1'
+fi