diff --git a/flake.nix b/flake.nix
index ed8ca4241..fef117d58 100644
--- a/flake.nix
+++ b/flake.nix
@@ -194,7 +194,7 @@
 
         buildDeps = calledPackage.buildInputs;
 
-        checkDeps = calledPackage.finalAttrs._checkInputs;
+        checkDeps = calledPackage.finalAttrs.passthru._checkInputs;
 
         internalApiDocsDeps = [
           buildPackages.doxygen
@@ -237,51 +237,40 @@
             echo "file installer $out/install" >> $out/nix-support/hydra-build-products
           '';
 
-      testNixVersions = pkgs: client: daemon: with commonDeps { inherit pkgs; }; with pkgs.lib; pkgs.stdenv.mkDerivation {
+      testNixVersions = pkgs: client: daemon: let
+        nix = pkgs.callPackage ./package.nix {
+          pname =
+            "nix-tests"
+            + lib.optionalString
+            (lib.versionAtLeast daemon.version "2.4pre20211005" &&
+            lib.versionAtLeast client.version "2.4pre20211005")
+            "-${client.version}-against-${daemon.version}";
+
+            inherit fileset;
+        };
+      in nix.overrideAttrs (prevAttrs: {
         NIX_DAEMON_PACKAGE = daemon;
         NIX_CLIENT_PACKAGE = client;
-        name =
-          "nix-tests"
-          + optionalString
-            (versionAtLeast daemon.version "2.4pre20211005" &&
-             versionAtLeast client.version "2.4pre20211005")
-            "-${client.version}-against-${daemon.version}";
-        inherit version;
 
-        src = fileset.toSource {
-          root = ./.;
-          fileset = fileset.intersection baseFiles (fileset.unions [
-            configureFiles
-            topLevelBuildFiles
-            functionalTestFiles
-          ]);
-        };
-
-        VERSION_SUFFIX = versionSuffix;
-
-        nativeBuildInputs = nativeBuildDeps;
-        buildInputs = buildDeps ++ awsDeps ++ checkDeps;
-        propagatedBuildInputs = propagatedDeps;
-
-        enableParallelBuilding = true;
-
-        configureFlags =
-          testConfigureFlags # otherwise configure fails
-          ++ [ "--disable-build" ];
         dontBuild = true;
         doInstallCheck = true;
 
+        configureFlags = [
+          "RAPIDCHECK_HEADERS=${lib.getDev pkgs.rapidcheck}/extras/gtest/include"
+          "--disable-build"
+        ];
+
         installPhase = ''
           mkdir -p $out
         '';
 
-        installCheckPhase = (optionalString pkgs.stdenv.hostPlatform.isDarwin ''
+        installCheckPhase = (lib.optionalString pkgs.stdenv.hostPlatform.isDarwin ''
           export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES
         '') + ''
           mkdir -p src/nix-channel
           make installcheck -j$NIX_BUILD_CORES -l$NIX_BUILD_CORES
         '';
-      };
+      });
 
       binaryTarball = nix: pkgs:
         let
diff --git a/package.nix b/package.nix
index 15c683cfe..f526f5867 100644
--- a/package.nix
+++ b/package.nix
@@ -88,24 +88,63 @@
     customMemoryManagement = false;
   };
 
- testConfigureFlags = [
-   "RAPIDCHECK_HEADERS=${lib.getDev rapidcheck}/extras/gtest/include"
+   testConfigureFlags = [
+     "RAPIDCHECK_HEADERS=${lib.getDev rapidcheck}/extras/gtest/include"
+   ];
+
+  configureFiles = fileset.unions [
+    ./.version
+    ./configure.ac
+    ./m4
+    # TODO: do we really need README.md? It doesn't seem used in the build.
+    ./README.md
+  ];
+
+  topLevelBuildFiles = fileset.unions [
+    ./local.mk
+    ./Makefile
+    ./Makefile.config.in
+    ./mk
+  ];
+
+ functionalTestFiles = fileset.unions [
+    ./tests/functional
+    ./tests/unit
+    (fileset.fileFilter (f: lib.strings.hasPrefix "nix-profile" f.name) ./scripts)
  ];
 
 in stdenv.mkDerivation (finalAttrs: {
   inherit pname version;
 
-  inherit src;
+  src = fileset.toSource {
+    root = ./.;
+    fileset = fileset.intersection baseFiles (fileset.unions ([
+      configureFiles
+      topLevelBuildFiles
+      functionalTestFiles
+      ./unit-test-data
+    ] ++ lib.optionals finalAttrs.doBuild [
+      ./boehmgc-coroutine-sp-fallback.diff
+      ./doc
+      ./misc
+      ./precompiled-headers.h
+      ./src
+      ./COPYING
+      ./scripts/local.mk
+    ]));
+  };
 
   VERSION_SUFFIX = versionSuffix;
 
-  outputs = [ "out" "dev" "doc" ];
+  outputs = [ "out" ]
+    ++ lib.optionals finalAttrs.doBuild [ "dev" "doc" ];
 
   doBuild = !(finalAttrs.dontBuild or false);
 
   nativeBuildInputs = [
     bison
     flex
+  ] ++ [
     (lib.getBin lowdown)
     mdbook
     mdbook-linkcheck
@@ -149,6 +188,9 @@ in stdenv.mkDerivation (finalAttrs: {
     rapidcheck
   ];
 
+  # FIXME(Qyriad): remove at the end of refactoring.
+  checkInputs = finalAttrs.passthru._checkInputs;
+
   propagatedBuildInputs = [
     boehmgc
     nlohmann_json
@@ -158,7 +200,7 @@ in stdenv.mkDerivation (finalAttrs: {
     boost
   ];
 
-  preConfigure = lib.optionalString (! stdenv.hostPlatform.isStatic) ''
+  preConfigure = lib.optionalString (finalAttrs.doBuild && (! stdenv.hostPlatform.isStatic)) ''
       # Copy libboost_context so we don't get all of Boost in our closure.
       # https://github.com/NixOS/nixpkgs/issues/45462
       mkdir -p $out/lib
@@ -221,7 +263,7 @@ in stdenv.mkDerivation (finalAttrs: {
     export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES
   '';
 
-  separateDebugInfo = !stdenv.hostPlatform.isStatic;
+  separateDebugInfo = !stdenv.hostPlatform.isStatic && finalAttrs.doBuild;
 
   strictDeps = true;