Merge pull request NixOS#9096 from NixOS/dont-rebuild-twice-on-ci

 Don't run the tests that require building if we're not building

(cherry picked from commit 8cfa582)
Change-Id: I6085ca6107349669407340d7a5e52639a2febc90

flake.nix

@@ -253,6 +253,7 @@
       testNixVersions = pkgs: client: daemon: with commonDeps { inherit pkgs; }; with pkgs.lib; pkgs.stdenv.mkDerivation {
         NIX_DAEMON_PACKAGE = daemon;
         NIX_CLIENT_PACKAGE = client;
+        HAVE_LOCAL_NIX_BUILD = false;
         name =
           "nix-tests"
           + optionalString
@@ -272,9 +273,13 @@
         enableParallelBuilding = true;
 
         configureFlags = testConfigureFlags; # otherwise configure fails
-        dontBuild = true;
         doInstallCheck = true;
 
+        buildPhase = ''
+          # Remove the source files to make sure that we're not accidentally rebuilding Nix
+          rm src/**/*.cc
+        '';
+
         installPhase = ''
           mkdir -p $out
         '';

tests/functional/local.mk

@@ -1,3 +1,7 @@
+# whether to run the tests that assume that we have a local build of
+# Nix
+HAVE_LOCAL_NIX_BUILD ?= 1
+
 nix_tests = \
   test-infra.sh \
   init.sh \
@@ -118,7 +122,6 @@ nix_tests = \
   flakes/show.sh \
   impure-derivations.sh \
   path-from-hash-part.sh \
-  test-libstoreconsumer.sh \
   toString-path.sh \
   read-only-store.sh \
   nested-sandboxing.sh
@@ -127,8 +130,12 @@ ifeq ($(HAVE_LIBCPUID), 1)
 	nix_tests += compute-levels.sh
 endif
 
-ifeq ($(BUILD_SHARED_LIBS), 1)
-	nix_tests += plugins.sh
+ifeq ($(HAVE_LOCAL_NIX_BUILD), 1)
+	nix_tests += test-libstoreconsumer.sh
+
+	ifeq ($(BUILD_SHARED_LIBS), 1)
+		nix_tests += plugins.sh
+	endif
 endif
 
 $(d)/test-libstoreconsumer.sh.test $(d)/test-libstoreconsumer.sh.test-debug: \