Convert VM tests to Python

Perl-based tests are deprecated since NixOS 20.03 and subsequently got
removed in NixOS 20.09, which effectively means that tests are going to
fail as soon as we build it with NixOS 20.09 or anything newer.

I've put "# fmt: off" at the start of every testScript, because
formatting with Black really messes up indentation and I don't think it
really adds anything in value or readability for inlined Python scripts.

Signed-off-by: aszlig <aszlig@nix.build>

4 files changed, 209 insertions, 186 deletions

diff --git a/tests/github-flakes.nix b/tests/github-flakes.nix
index a47610d9a..2de3e2bc0 100644
--- a/tests/github-flakes.nix
+++ b/tests/github-flakes.nix
@@ -1,6 +1,6 @@
 { nixpkgs, system, overlay }:
 
-with import (nixpkgs + "/nixos/lib/testing.nix") {
+with import (nixpkgs + "/nixos/lib/testing-python.nix") {
   inherit system;
   extraConfigurations = [ { nixpkgs.overlays = [ overlay ]; } ];
 };
@@ -113,36 +113,37 @@ makeTest (
         };
     };
 
-  testScript = { nodes }:
-    ''
-      use POSIX qw(strftime);
-
-      startAll;
+  testScript = { nodes }: ''
+    # fmt: off
+    import json
+    import time
 
-      $github->waitForUnit("httpd.service");
+    start_all()
 
-      $client->succeed("curl -v https://github.com/ >&2");
+    github.wait_for_unit("httpd.service")
 
-      $client->succeed("nix registry list | grep nixpkgs");
+    client.succeed("curl -v https://github.com/ >&2")
+    client.succeed("nix registry list | grep nixpkgs")
 
-      $client->succeed("nix flake info nixpkgs --json | jq -r .revision") eq "${nixpkgs.rev}\n"
-        or die "revision mismatch";
+    rev = client.succeed("nix flake info nixpkgs --json | jq -r .revision")
+    assert rev.strip() == "${nixpkgs.rev}", "revision mismatch"
 
-      $client->succeed("nix registry pin nixpkgs");
+    client.succeed("nix registry pin nixpkgs")
 
-      $client->succeed("nix flake info nixpkgs --tarball-ttl 0 >&2");
+    client.succeed("nix flake info nixpkgs --tarball-ttl 0 >&2")
 
-      # Shut down the web server. The flake should be cached on the client.
-      $github->succeed("systemctl stop httpd.service");
+    # Shut down the web server. The flake should be cached on the client.
+    github.succeed("systemctl stop httpd.service")
 
-      my $date = $client->succeed("nix flake info nixpkgs --json | jq -M .lastModified");
-      strftime("%Y%m%d%H%M%S", gmtime($date)) eq "${nixpkgs.lastModifiedDate}" or die "time mismatch";
+    info = json.loads(client.succeed("nix flake info nixpkgs --json"))
+    date = time.strftime("%Y%m%d%H%M%S", time.gmtime(info['lastModified']))
+    assert date == "${nixpkgs.lastModifiedDate}", "time mismatch"
 
-      $client->succeed("nix build nixpkgs#hello");
+    client.succeed("nix build nixpkgs#hello")
 
-      # The build shouldn't fail even with --tarball-ttl 0 (the server
-      # being down should not be a fatal error).
-      $client->succeed("nix build nixpkgs#fuse --tarball-ttl 0");
-    '';
+    # The build shouldn't fail even with --tarball-ttl 0 (the server
+    # being down should not be a fatal error).
+    client.succeed("nix build nixpkgs#fuse --tarball-ttl 0")
+  '';
 
 })
diff --git a/tests/nix-copy-closure.nix b/tests/nix-copy-closure.nix
index 9c9d119b7..68f9c70b3 100644
--- a/tests/nix-copy-closure.nix
+++ b/tests/nix-copy-closure.nix
@@ -2,7 +2,7 @@
 
 { nixpkgs, system, overlay }:
 
-with import (nixpkgs + "/nixos/lib/testing.nix") {
+with import (nixpkgs + "/nixos/lib/testing-python.nix") {
   inherit system;
   extraConfigurations = [ { nixpkgs.overlays = [ overlay ]; } ];
 };
@@ -25,41 +25,46 @@ makeTest (let pkgA = pkgs.cowsay; pkgB = pkgs.wget; pkgC = pkgs.hello; in {
         };
     };
 
-  testScript = { nodes }:
-    ''
-      startAll;
+  testScript = { nodes }: ''
+    # fmt: off
+    import subprocess
 
-      # Create an SSH key on the client.
-      my $key = `${pkgs.openssh}/bin/ssh-keygen -t ed25519 -f key -N ""`;
-      $client->succeed("mkdir -m 700 /root/.ssh");
-      $client->copyFileFromHost("key", "/root/.ssh/id_ed25519");
-      $client->succeed("chmod 600 /root/.ssh/id_ed25519");
+    start_all()
 
-      # Install the SSH key on the server.
-      $server->succeed("mkdir -m 700 /root/.ssh");
-      $server->copyFileFromHost("key.pub", "/root/.ssh/authorized_keys");
-      $server->waitForUnit("sshd");
-      $client->waitForUnit("network.target");
-      $client->succeed("ssh -o StrictHostKeyChecking=no " . $server->name() . " 'echo hello world'");
+    # Create an SSH key on the client.
+    subprocess.run([
+      "${pkgs.openssh}/bin/ssh-keygen", "-t", "ed25519", "-f", "key", "-N", ""
+    ], capture_output=True, check=True)
 
-      # Copy the closure of package A from the client to the server.
-      $server->fail("nix-store --check-validity ${pkgA}");
-      $client->succeed("nix-copy-closure --to server --gzip ${pkgA} >&2");
-      $server->succeed("nix-store --check-validity ${pkgA}");
+    client.succeed("mkdir -m 700 /root/.ssh")
+    client.copy_from_host("key", "/root/.ssh/id_ed25519")
+    client.succeed("chmod 600 /root/.ssh/id_ed25519")
 
-      # Copy the closure of package B from the server to the client.
-      $client->fail("nix-store --check-validity ${pkgB}");
-      $client->succeed("nix-copy-closure --from server --gzip ${pkgB} >&2");
-      $client->succeed("nix-store --check-validity ${pkgB}");
+    # Install the SSH key on the server.
+    server.succeed("mkdir -m 700 /root/.ssh")
+    server.copy_from_host("key.pub", "/root/.ssh/authorized_keys")
+    server.wait_for_unit("sshd")
+    client.wait_for_unit("network.target")
+    client.succeed(f"ssh -o StrictHostKeyChecking=no {server.name} 'echo hello world'")
 
-      # Copy the closure of package C via the SSH substituter.
-      $client->fail("nix-store -r ${pkgC}");
-      # FIXME
-      #$client->succeed(
-      #  "nix-store --option use-ssh-substituter true"
-      #  . " --option ssh-substituter-hosts root\@server"
-      #  . " -r ${pkgC} >&2");
-      #$client->succeed("nix-store --check-validity ${pkgC}");
-    '';
+    # Copy the closure of package A from the client to the server.
+    server.fail("nix-store --check-validity ${pkgA}")
+    client.succeed("nix-copy-closure --to server --gzip ${pkgA} >&2")
+    server.succeed("nix-store --check-validity ${pkgA}")
 
+    # Copy the closure of package B from the server to the client.
+    client.fail("nix-store --check-validity ${pkgB}")
+    client.succeed("nix-copy-closure --from server --gzip ${pkgB} >&2")
+    client.succeed("nix-store --check-validity ${pkgB}")
+
+    # Copy the closure of package C via the SSH substituter.
+    client.fail("nix-store -r ${pkgC}")
+    # FIXME
+    # client.succeed(
+    #   "nix-store --option use-ssh-substituter true"
+    #   " --option ssh-substituter-hosts root\@server"
+    #   " -r ${pkgC} >&2"
+    # )
+    # client.succeed("nix-store --check-validity ${pkgC}")
+  '';
 })
diff --git a/tests/remote-builds.nix b/tests/remote-builds.nix
index 153956619..305c82394 100644
--- a/tests/remote-builds.nix
+++ b/tests/remote-builds.nix
@@ -2,7 +2,7 @@
 
 { nixpkgs, system, overlay }:
 
-with import (nixpkgs + "/nixos/lib/testing.nix") {
+with import (nixpkgs + "/nixos/lib/testing-python.nix") {
   inherit system;
   extraConfigurations = [ { nixpkgs.overlays = [ overlay ]; } ];
 };
@@ -66,44 +66,46 @@ in
         };
     };
 
-  testScript = { nodes }:
-    ''
-      startAll;
-
-      # Create an SSH key on the client.
-      my $key = `${pkgs.openssh}/bin/ssh-keygen -t ed25519 -f key -N ""`;
-      $client->succeed("mkdir -p -m 700 /root/.ssh");
-      $client->copyFileFromHost("key", "/root/.ssh/id_ed25519");
-      $client->succeed("chmod 600 /root/.ssh/id_ed25519");
-
-      # Install the SSH key on the builders.
-      $client->waitForUnit("network.target");
-      foreach my $builder ($builder1, $builder2) {
-          $builder->succeed("mkdir -p -m 700 /root/.ssh");
-          $builder->copyFileFromHost("key.pub", "/root/.ssh/authorized_keys");
-          $builder->waitForUnit("sshd");
-          $client->succeed("ssh -o StrictHostKeyChecking=no " . $builder->name() . " 'echo hello world'");
-      }
-
-      # Perform a build and check that it was performed on the builder.
-      my $out = $client->succeed(
-        "nix-build ${expr nodes.client.config 1} 2> build-output",
-        "grep -q Hello build-output"
-      );
-      $builder1->succeed("test -e $out");
-
-      # And a parallel build.
-      my ($out1, $out2) = split /\s/,
-          $client->succeed('nix-store -r $(nix-instantiate ${expr nodes.client.config 2})\!out $(nix-instantiate ${expr nodes.client.config 3})\!out');
-      $builder1->succeed("test -e $out1 -o -e $out2");
-      $builder2->succeed("test -e $out1 -o -e $out2");
-
-      # And a failing build.
-      $client->fail("nix-build ${expr nodes.client.config 5}");
-
-      # Test whether the build hook automatically skips unavailable builders.
-      $builder1->block;
-      $client->succeed("nix-build ${expr nodes.client.config 4}");
-    '';
-
+  testScript = { nodes }: ''
+    # fmt: off
+    import subprocess
+
+    start_all()
+
+    # Create an SSH key on the client.
+    subprocess.run([
+      "${pkgs.openssh}/bin/ssh-keygen", "-t", "ed25519", "-f", "key", "-N", ""
+    ], capture_output=True, check=True)
+    client.succeed("mkdir -p -m 700 /root/.ssh")
+    client.copy_from_host("key", "/root/.ssh/id_ed25519")
+    client.succeed("chmod 600 /root/.ssh/id_ed25519")
+
+    # Install the SSH key on the builders.
+    client.wait_for_unit("network.target")
+    for builder in [builder1, builder2]:
+      builder.succeed("mkdir -p -m 700 /root/.ssh")
+      builder.copy_from_host("key.pub", "/root/.ssh/authorized_keys")
+      builder.wait_for_unit("sshd")
+      client.succeed(f"ssh -o StrictHostKeyChecking=no {builder.name} 'echo hello world'")
+
+    # Perform a build and check that it was performed on the builder.
+    out = client.succeed(
+      "nix-build ${expr nodes.client.config 1} 2> build-output",
+      "grep -q Hello build-output"
+    )
+    builder1.succeed(f"test -e {out}")
+
+    # And a parallel build.
+    paths = client.succeed(r'nix-store -r $(nix-instantiate ${expr nodes.client.config 2})\!out $(nix-instantiate ${expr nodes.client.config 3})\!out')
+    out1, out2 = paths.split()
+    builder1.succeed(f"test -e {out1} -o -e {out2}")
+    builder2.succeed(f"test -e {out1} -o -e {out2}")
+
+    # And a failing build.
+    client.fail("nix-build ${expr nodes.client.config 5}")
+
+    # Test whether the build hook automatically skips unavailable builders.
+    builder1.block()
+    client.succeed("nix-build ${expr nodes.client.config 4}")
+  '';
 })
diff --git a/tests/setuid.nix b/tests/setuid.nix
index 6f2f7d392..8d31a18be 100644
--- a/tests/setuid.nix
+++ b/tests/setuid.nix
@@ -2,7 +2,7 @@
 
 { nixpkgs, system, overlay }:
 
-with import (nixpkgs + "/nixos/lib/testing.nix") {
+with import (nixpkgs + "/nixos/lib/testing-python.nix") {
   inherit system;
   extraConfigurations = [ { nixpkgs.overlays = [ overlay ]; } ];
 };
@@ -17,94 +17,109 @@ makeTest {
       virtualisation.pathsInNixDB = [ pkgs.stdenv pkgs.pkgsi686Linux.stdenv ];
     };
 
-  testScript = { nodes }:
-    ''
-      startAll;
-
-      # Copying to /tmp should succeed.
-      $machine->succeed('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" {} "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
-
-      $machine->succeed("rm /tmp/id");
-
-      # Creating a setuid binary should fail.
-      $machine->fail('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" {} "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-        chmod 4755 /tmp/id
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
-
-      $machine->succeed("rm /tmp/id");
-
-      # Creating a setgid binary should fail.
-      $machine->fail('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" {} "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-        chmod 2755 /tmp/id
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
-
-      $machine->succeed("rm /tmp/id");
-
-      # The checks should also work on 32-bit binaries.
-      $machine->fail('nix-build --no-sandbox -E \'(with import <nixpkgs> { system = "i686-linux"; }; runCommand "foo" {} "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-        chmod 2755 /tmp/id
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
-
-      $machine->succeed("rm /tmp/id");
-
-      # The tests above use fchmodat(). Test chmod() as well.
-      $machine->succeed('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-        perl -e \"chmod 0666, qw(/tmp/id) or die\"
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 666 ]]');
-
-      $machine->succeed("rm /tmp/id");
-
-      $machine->fail('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-        perl -e \"chmod 04755, qw(/tmp/id) or die\"
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
-
-      $machine->succeed("rm /tmp/id");
-
-      # And test fchmod().
-      $machine->succeed('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-        perl -e \"my \\\$x; open \\\$x, qw(/tmp/id); chmod 01750, \\\$x or die\"
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 1750 ]]');
-
-      $machine->succeed("rm /tmp/id");
-
-      $machine->fail('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
-        mkdir -p $out
-        cp ${pkgs.coreutils}/bin/id /tmp/id
-        perl -e \"my \\\$x; open \\\$x, qw(/tmp/id); chmod 04777, \\\$x or die\"
-      ")\' ');
-
-      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
-
-      $machine->succeed("rm /tmp/id");
-    '';
-
+  testScript = { nodes }: ''
+    # fmt: off
+    start_all()
+
+    # Copying to /tmp should succeed.
+    machine.succeed(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" {} "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]')
+
+    machine.succeed("rm /tmp/id")
+
+    # Creating a setuid binary should fail.
+    machine.fail(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" {} "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+      chmod 4755 /tmp/id
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]')
+
+    machine.succeed("rm /tmp/id")
+
+    # Creating a setgid binary should fail.
+    machine.fail(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" {} "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+      chmod 2755 /tmp/id
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]')
+
+    machine.succeed("rm /tmp/id")
+
+    # The checks should also work on 32-bit binaries.
+    machine.fail(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> { system = "i686-linux"; }; runCommand "foo" {} "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+      chmod 2755 /tmp/id
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]')
+
+    machine.succeed("rm /tmp/id")
+
+    # The tests above use fchmodat(). Test chmod() as well.
+    machine.succeed(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+      perl -e \"chmod 0666, qw(/tmp/id) or die\"
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 666 ]]')
+
+    machine.succeed("rm /tmp/id")
+
+    machine.fail(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+      perl -e \"chmod 04755, qw(/tmp/id) or die\"
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]')
+
+    machine.succeed("rm /tmp/id")
+
+    # And test fchmod().
+    machine.succeed(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+      perl -e \"my \\\$x; open \\\$x, qw(/tmp/id); chmod 01750, \\\$x or die\"
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 1750 ]]')
+
+    machine.succeed("rm /tmp/id")
+
+    machine.fail(r"""
+    nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } "
+      mkdir -p $out
+      cp ${pkgs.coreutils}/bin/id /tmp/id
+      perl -e \"my \\\$x; open \\\$x, qw(/tmp/id); chmod 04777, \\\$x or die\"
+    ")'
+    """.strip())
+
+    machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]')
+
+    machine.succeed("rm /tmp/id")
+  '';
 }