Restore tests and script deleted in b8661825

tests/lib/config.nix

@@ -0,0 +1,11 @@
+{
+    security.dhparams.defaultBitSize = 16; # really low for quicker tests
+
+    # For slow non-kvm tests.
+    # nixos/modules/testing/test-instrumentation.nix also sets this. I don't know if there's a better way than etc to override theirs.
+    environment.etc."systemd/system.conf.d/bigdefaulttimeout.conf".text = ''
+      [Manager]
+      # Allow extremely slow start (default for test-VMs is 5 minutes)
+      DefaultTimeoutStartSec=15min
+    '';
+}

tests/lib/pkgs.nokvm.nix

@@ -0,0 +1,31 @@
+let
+    pkgs = (import <nixpkgs> { system = builtins.currentSystem; config = {}; });
+    patchedMachinePM = pkgs.writeTextFile {
+        name = "Machine.pm.patched-to-wait-longer-for-vm";
+        text = builtins.replaceStrings ["alarm 600;"] ["alarm 1200;"] (builtins.readFile (<nixpkgs>+"/nixos/lib/test-driver/Machine.pm"));
+    };
+in
+(pkgs // {
+    qemu_test = with pkgs; stdenv.mkDerivation {
+        name = "qemu_test_no_kvm";
+        buildInputs = [ coreutils qemu_test ];
+        inherit qemu_test;
+        inherit coreutils;
+        builder = builtins.toFile "builder.sh" ''
+            PATH=$coreutils/bin:$PATH
+            mkdir -p $out/bin
+            cp $qemu_test/bin/* $out/bin/
+            ln -sf $out/bin/qemu-system-${stdenv.hostPlatform.qemuArch} $out/bin/qemu-kvm
+        '';
+    };
+    stdenv = pkgs.stdenv // {
+        mkDerivation = args: (pkgs.stdenv.mkDerivation (args // (
+            pkgs.lib.optionalAttrs (args.name == "nixos-test-driver") {
+                installPhase = args.installPhase + ''
+                    rm $libDir/Machine.pm
+                    cp ${patchedMachinePM} $libDir/Machine.pm
+                '';
+            }
+        )));
+    };
+})