diff --git a/nix/cargo-pgrx/mkPgrxExtension.nix b/nix/cargo-pgrx/mkPgrxExtension.nix
index 0bf99e3de4..cee5eae1a8 100644
--- a/nix/cargo-pgrx/mkPgrxExtension.nix
+++ b/nix/cargo-pgrx/mkPgrxExtension.nix
@@ -42,7 +42,7 @@ let
           import (builtins.fetchTarball {
             url = "https://channels.nixos.org/nixos-22.11/nixexprs.tar.xz";
             sha256 = "1j7h75a9hwkkm97jicky5rhvzkdwxsv5v46473rl6agvq2sj97y1";
-          }) { system = stdenv.hostPlatform.system; }
+          }) { inherit (stdenv.hostPlatform) system; }
         );
       in
       rustPlatform.bindgenHook.overrideAttrs {
diff --git a/nix/checks.nix b/nix/checks.nix
index a721964761..4af756f1d4 100644
--- a/nix/checks.nix
+++ b/nix/checks.nix
@@ -439,21 +439,19 @@
             ;
           devShell = self'.devShells.default;
         }
-        // pkgs.lib.optionalAttrs (pkgs.stdenv.isLinux) (
-          {
-            inherit (self'.packages)
-              postgresql_15_debug
-              postgresql_15_src
-              postgresql_orioledb-17_debug
-              postgresql_orioledb-17_src
-              postgresql_17_debug
-              postgresql_17_src
-              ;
-          }
-          // (import ./ext/tests {
-            inherit self;
-            inherit pkgs;
-          })
-        );
+        // (import ./ext/tests {
+          inherit self;
+          inherit pkgs;
+        })
+        // pkgs.lib.optionalAttrs (pkgs.stdenv.isLinux) {
+          inherit (self'.packages)
+            postgresql_15_debug
+            postgresql_15_src
+            postgresql_orioledb-17_debug
+            postgresql_orioledb-17_src
+            postgresql_17_debug
+            postgresql_17_src
+            ;
+        };
     };
 }
diff --git a/nix/ext/tests/default.nix b/nix/ext/tests/default.nix
index b0918ae22b..6b02f1562d 100644
--- a/nix/ext/tests/default.nix
+++ b/nix/ext/tests/default.nix
@@ -16,7 +16,7 @@ let
 
       installedExtension =
         postgresMajorVersion:
-        self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+        self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
           pname
         }";
       versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -25,7 +25,7 @@ let
         let
           majorVersion =
             if postgresql.isOrioleDB then "orioledb-17" else lib.versions.major postgresql.version;
-          pkg = pkgs.buildEnv {
+          pkg = pkgs.pkgsLinux.buildEnv {
             name = "postgresql-${majorVersion}-${pname}";
             paths = [
               postgresql
@@ -33,7 +33,7 @@ let
               (installedExtension majorVersion)
             ]
             ++ lib.optional (postgresql.isOrioleDB
-            ) self.legacyPackages.${pkgs.stdenv.hostPlatform.system}.psql_orioledb-17.exts.orioledb;
+            ) self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.psql_orioledb-17.exts.orioledb;
             passthru = {
               inherit (postgresql) version psqlSchema;
               lib = pkg;
@@ -42,7 +42,7 @@ let
               withoutJIT = pkg;
               installedExtensions = [ (installedExtension majorVersion) ];
             };
-            nativeBuildInputs = [ pkgs.makeWrapper ];
+            nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
             pathsToLink = [
               "/"
               "/bin"
@@ -56,27 +56,21 @@ let
           };
         in
         pkg;
-      psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-      psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+      psql_15 =
+        postgresqlWithExtension
+          self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+      psql_17 =
+        postgresqlWithExtension
+          self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
       orioledb_17 =
         postgresqlWithExtension
-          self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17;
+          self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
     in
-    self.inputs.nixpkgs.lib.nixos.runTest {
+    pkgs.testers.runNixOSTest {
       name = pname;
-      hostPkgs = pkgs;
       nodes.server =
         { config, ... }:
         {
-          virtualisation = {
-            forwardPorts = [
-              {
-                from = "host";
-                host.port = 13022;
-                guest.port = 22;
-              }
-            ];
-          };
           services.openssh = {
             enable = true;
           };
@@ -153,7 +147,8 @@ let
           specialisation.orioledb17.configuration = {
             services.postgresql = {
               package = lib.mkForce (
-                postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17
+                postgresqlWithExtension
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17
               );
               settings = lib.mkForce (
                 ((installedExtension "17").defaultSettings or { })
@@ -191,7 +186,7 @@ let
                 let
                   newPostgresql =
                     postgresqlWithExtension
-                      self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17;
+                      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
                 in
                 ''
                   if [[ -z "${newPostgresql.psqlSchema}" ]]; then
diff --git a/nix/ext/tests/http.nix b/nix/ext/tests/http.nix
index 2879ad2ca2..edc2d31681 100644
--- a/nix/ext/tests/http.nix
+++ b/nix/ext/tests/http.nix
@@ -2,9 +2,10 @@
 let
   pname = "http";
   inherit (pkgs) lib;
+  mockServer = ../../tests/http-mock-server.py;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -13,7 +14,7 @@ let
     let
       majorVersion =
         if postgresql.isOrioleDB then "orioledb-17" else lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -21,7 +22,7 @@ let
           (installedExtension majorVersion)
         ]
         ++ lib.optional (postgresql.isOrioleDB
-        ) self.legacyPackages.${pkgs.stdenv.hostPlatform.system}.psql_orioledb-17.exts.orioledb;
+        ) self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.psql_orioledb-17.exts.orioledb;
         passthru = {
           inherit (postgresql) version psqlSchema;
           installedExtensions = [ (installedExtension majorVersion) ];
@@ -30,7 +31,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -44,34 +45,30 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
   orioledb_17 =
     postgresqlWithExtension
-      self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17;
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
 
       services.postgresql = {
         enable = true;
-        package = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+        package =
+          postgresqlWithExtension
+            self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
         settings = (installedExtension "15").defaultSettings or { };
         authentication = ''
           local all postgres peer map=postgres
@@ -89,24 +86,40 @@ self.inputs.nixpkgs.lib.nixos.runTest {
         ];
         initialScript = pkgs.writeText "init-postgres" ''
           CREATE TABLE IF NOT EXISTS test_config (key TEXT PRIMARY KEY, value TEXT);
-          INSERT INTO test_config (key, value) VALUES ('http_mock_port', '8880') ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value;
         '';
       };
 
       systemd.services.http-mock-server = {
         wantedBy = [ "multi-user.target" ];
+        before = [ "postgresql.service" ];
         serviceConfig = {
           Type = "simple";
+          Restart = "on-failure";
+          RestartSec = "2";
+          TimeoutStartSec = "30";
+          User = "root";
+        };
+        environment = {
+          HTTP_MOCK_PORT_FILE = "/tmp/http-mock-port";
+          PYTHONUNBUFFERED = "1";
         };
         script = ''
-          ${pkgs.python3}/bin/python3 ${../../tests/http-mock-server.py}
+          # Ensure temp directory exists
+          mkdir -p /tmp
+
+          # Start the mock server
+          exec ${pkgs.pkgsLinux.python3}/bin/python3 ${mockServer}
         '';
       };
 
+      systemd.services.postgresql = {
+        after = [ "http-mock-server.service" ];
+      };
+
       specialisation.postgresql17.configuration = {
         services.postgresql = {
           package = lib.mkForce (
-            postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17
+            postgresqlWithExtension self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17
           );
           settings = ((installedExtension "17").defaultSettings or { });
         };
@@ -124,10 +137,10 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             let
               oldPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
               newPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
               oldDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${oldPostgresql.psqlSchema}";
               newDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${newPostgresql.psqlSchema}";
             in
@@ -152,7 +165,8 @@ self.inputs.nixpkgs.lib.nixos.runTest {
       specialisation.orioledb17.configuration = {
         services.postgresql = {
           package = lib.mkForce (
-            postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17
+            postgresqlWithExtension
+              self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17
           );
           settings = lib.mkForce (
             ((installedExtension "17").defaultSettings or { })
@@ -175,7 +189,6 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             pkgs.writeText "init-postgres-with-orioledb" ''
               CREATE EXTENSION orioledb CASCADE;
               CREATE TABLE IF NOT EXISTS test_config (key TEXT PRIMARY KEY, value TEXT);
-              INSERT INTO test_config (key, value) VALUES ('http_mock_port', '8880') ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value;
             ''
           );
         };
@@ -194,7 +207,7 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             let
               newPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
             in
             ''
               if [[ -z "${newPostgresql.psqlSchema}" ]]; then
@@ -243,8 +256,37 @@ self.inputs.nixpkgs.lib.nixos.runTest {
       start_all()
 
       server.wait_for_unit("multi-user.target")
+      server.wait_for_unit("http-mock-server.service")
       server.wait_for_unit("postgresql.service")
 
+      # Read the HTTP mock port and configure it in PostgreSQL
+      # Wait for the port file to be created with retry logic
+      server.succeed("""
+        for i in {1..30}; do
+          if [ -f /tmp/http-mock-port ]; then
+            break
+          fi
+          echo "Waiting for HTTP mock server port file... ($i/30)"
+          sleep 1
+        done
+        
+        if [ ! -f /tmp/http-mock-port ]; then
+          echo "ERROR: HTTP mock server port file not found after 30 seconds"
+          systemctl status http-mock-server.service || true
+          journalctl -u http-mock-server.service --no-pager || true
+          exit 1
+        fi
+      """)
+
+      http_port = server.succeed("cat /tmp/http-mock-port").strip()
+      server.succeed(f"""
+        sudo -u postgres psql -d postgres -c '
+          CREATE TABLE IF NOT EXISTS test_config (key TEXT PRIMARY KEY, value TEXT);
+          INSERT INTO test_config (key, value) VALUES ('"'"'http_mock_port'"'"', '"'"'{http_port}'"'"')
+          ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value;
+        '
+      """)
+
       test = PostgresExtensionTest(server, extension_name, versions, sql_test_directory, support_upgrade, ext_schema, lib_name)
       test.create_schema()
 
@@ -269,6 +311,14 @@ self.inputs.nixpkgs.lib.nixos.runTest {
         server.succeed(
           "${pg17-configuration}/bin/switch-to-configuration test >&2"
         )
+        server.wait_for_unit("postgresql.service")
+        # Reconfigure the HTTP mock port after switching PostgreSQL version
+        server.succeed(f"""
+          sudo -u postgres psql -d postgres -c '
+            INSERT INTO test_config (key, value) VALUES ('"'"'http_mock_port'"'"', '"'"'{http_port}'"'"')
+            ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value;
+          '
+        """)
 
       with subtest("Check last version of the extension after postgresql upgrade"):
         test.assert_version_matches(last_version)
@@ -289,6 +339,14 @@ self.inputs.nixpkgs.lib.nixos.runTest {
         server.succeed(
           "${orioledb17-configuration}/bin/switch-to-configuration test >&2"
         )
+        server.wait_for_unit("postgresql.service")
+        # Reconfigure the HTTP mock port after switching to orioledb
+        server.succeed(f"""
+          sudo -u postgres psql -d postgres -c '
+            INSERT INTO test_config (key, value) VALUES ('"'"'http_mock_port'"'"', '"'"'{http_port}'"'"')
+            ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value;
+          '
+        """)
         installed_extensions=test.run_sql("""SELECT extname FROM pg_extension WHERE extname = 'orioledb';""")
         assert "orioledb" in installed_extensions
         test.create_schema()
diff --git a/nix/ext/tests/index_advisor.nix b/nix/ext/tests/index_advisor.nix
index 564ec350bc..b936cb0369 100644
--- a/nix/ext/tests/index_advisor.nix
+++ b/nix/ext/tests/index_advisor.nix
@@ -4,14 +4,14 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.system}."psql_${postgresMajorVersion}".exts.index_advisor;
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts.index_advisor;
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
   postgresqlWithExtension =
     postgresql:
     let
       majorVersion =
         if postgresql.isOrioleDB then "orioledb-17" else lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -19,7 +19,7 @@ let
           (installedExtension majorVersion)
         ]
         ++ lib.optional (postgresql.isOrioleDB
-        ) self.legacyPackages.${pkgs.system}.psql_orioledb-17.exts.orioledb;
+        ) self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.psql_orioledb-17.exts.orioledb;
         passthru = {
           inherit (postgresql) version psqlSchema;
           installedExtensions = [ (installedExtension majorVersion) ];
@@ -28,7 +28,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -42,25 +42,21 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.system}.postgresql_17;
-  orioledb_17 = postgresqlWithExtension self.packages.${pkgs.system}.postgresql_orioledb-17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
+  orioledb_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
@@ -130,7 +126,10 @@ self.inputs.nixpkgs.lib.nixos.runTest {
 
       specialisation.orioledb17.configuration = {
         services.postgresql = {
-          package = lib.mkForce (postgresqlWithExtension self.packages.${pkgs.system}.postgresql_orioledb-17);
+          package = lib.mkForce (
+            postgresqlWithExtension
+              self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17
+          );
           settings = lib.mkForce (
             ((installedExtension "17").defaultSettings or { })
             // {
@@ -167,7 +166,7 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             let
               newPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
             in
             ''
               if [[ -z "${newPostgresql.psqlSchema}" ]]; then
diff --git a/nix/ext/tests/orioledb.nix b/nix/ext/tests/orioledb.nix
index de50710b50..bb1a3125f1 100644
--- a/nix/ext/tests/orioledb.nix
+++ b/nix/ext/tests/orioledb.nix
@@ -6,24 +6,24 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
           postgresql.lib
-          (self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_orioledb-17".exts.orioledb)
+          (self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_orioledb-17".exts.orioledb)
         ];
         passthru = {
           inherit (postgresql) version psqlSchema;
           installedExtensions = [
-            (self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_orioledb-17".exts.orioledb)
+            (self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_orioledb-17".exts.orioledb)
           ];
           lib = pkg;
           withPackages = _: pkg;
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -39,23 +39,13 @@ let
     pkg;
   psql_orioledb =
     postgresqlWithExtension
-      self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17;
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
diff --git a/nix/ext/tests/pg_plan_filter.nix b/nix/ext/tests/pg_plan_filter.nix
index f8d1c9ca63..30e1170e01 100644
--- a/nix/ext/tests/pg_plan_filter.nix
+++ b/nix/ext/tests/pg_plan_filter.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -41,18 +41,21 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
       services.postgresql = {
         enable = true;
-        package = (postgresqlWithExtension psql_15);
+        package = psql_15;
         settings = (installedExtension "15").defaultSettings or { };
       };
 
diff --git a/nix/ext/tests/pg_repack.nix b/nix/ext/tests/pg_repack.nix
index c81e29b2d1..7ca0da128d 100644
--- a/nix/ext/tests/pg_repack.nix
+++ b/nix/ext/tests/pg_repack.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -42,28 +42,20 @@ let
     in
     pkg;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
 
       services.postgresql = {
         enable = true;
-        package = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+        package =
+          postgresqlWithExtension
+            self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
         enableTCPIP = true;
         authentication = ''
           local all postgres peer map=postgres
@@ -86,7 +78,7 @@ self.inputs.nixpkgs.lib.nixos.runTest {
       specialisation.postgresql17.configuration = {
         services.postgresql = {
           package = lib.mkForce (
-            postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17
+            postgresqlWithExtension self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17
           );
         };
 
@@ -103,10 +95,10 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             let
               oldPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
               newPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
               oldDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${oldPostgresql.psqlSchema}";
               newDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${newPostgresql.psqlSchema}";
             in
diff --git a/nix/ext/tests/pg_safeupdate.nix b/nix/ext/tests/pg_safeupdate.nix
index 4f168f8b0a..83c2b080b0 100644
--- a/nix/ext/tests/pg_safeupdate.nix
+++ b/nix/ext/tests/pg_safeupdate.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -41,18 +41,21 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
       services.postgresql = {
         enable = true;
-        package = (postgresqlWithExtension psql_15);
+        package = psql_15;
         settings = (installedExtension "15").defaultSettings or { };
       };
 
diff --git a/nix/ext/tests/pgjwt.nix b/nix/ext/tests/pgjwt.nix
index 2f0cc9efcd..39fcd18f66 100644
--- a/nix/ext/tests/pgjwt.nix
+++ b/nix/ext/tests/pgjwt.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -41,25 +41,18 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
-
       services.postgresql = {
         enable = true;
         package = psql_15;
diff --git a/nix/ext/tests/pgmq.nix b/nix/ext/tests/pgmq.nix
index 3e2dc7f919..eac0c350d0 100644
--- a/nix/ext/tests/pgmq.nix
+++ b/nix/ext/tests/pgmq.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -41,18 +41,21 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
-  name = "timescaledb";
-  hostPkgs = pkgs;
+pkgs.testers.runNixOSTest {
+  name = "pgmq";
   nodes.server =
     { config, ... }:
     {
       services.postgresql = {
         enable = true;
-        package = (postgresqlWithExtension psql_15);
+        package = psql_15;
         authentication = ''
           local all postgres peer map=postgres
           local all all peer map=root
diff --git a/nix/ext/tests/pgroonga.nix b/nix/ext/tests/pgroonga.nix
index 4316d4a720..ee9c505c42 100644
--- a/nix/ext/tests/pgroonga.nix
+++ b/nix/ext/tests/pgroonga.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -41,24 +41,18 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
@@ -83,11 +77,11 @@ self.inputs.nixpkgs.lib.nixos.runTest {
         ];
       };
       systemd.services.postgresql.environment.MECAB_DICDIR = "${
-        self.packages.${pkgs.stdenv.hostPlatform.system}.mecab-naist-jdic
+        self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.mecab-naist-jdic
       }/lib/mecab/dic/naist-jdic";
-      systemd.services.postgresql.environment.MECAB_CONFIG = "${pkgs.mecab}/bin/mecab-config";
+      systemd.services.postgresql.environment.MECAB_CONFIG = "${pkgs.pkgsLinux.mecab}/bin/mecab-config";
       systemd.services.postgresql.environment.GRN_PLUGINS_DIR = "${
-        self.packages.${pkgs.stdenv.hostPlatform.system}.supabase-groonga
+        self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.supabase-groonga
       }/lib/groonga/plugins";
 
       specialisation.postgresql17.configuration = {
diff --git a/nix/ext/tests/pgrouting.nix b/nix/ext/tests/pgrouting.nix
index 5a023d5caa..845246d8e6 100644
--- a/nix/ext/tests/pgrouting.nix
+++ b/nix/ext/tests/pgrouting.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,16 +12,17 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
           postgresql.lib
           (installedExtension majorVersion)
-          (self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${majorVersion}".exts.postgis)
+          (self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${majorVersion}".exts.postgis
+          )
         ]
         ++ lib.optional (postgresql.isOrioleDB) (
-          self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_orioledb-17".exts.orioledb
+          self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_orioledb-17".exts.orioledb
         );
         passthru = {
           inherit (postgresql) version psqlSchema;
@@ -31,7 +32,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -46,24 +47,14 @@ let
     in
     pkg;
   pg_regress = pkgs.callPackage ../pg_regress.nix {
-    postgresql = self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+    postgresql = self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
   };
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
@@ -73,13 +64,15 @@ self.inputs.nixpkgs.lib.nixos.runTest {
 
       services.postgresql = {
         enable = true;
-        package = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+        package =
+          postgresqlWithExtension
+            self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
       };
 
       specialisation.postgresql17.configuration = {
         services.postgresql = {
           package = lib.mkForce (
-            postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17
+            postgresqlWithExtension self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17
           );
         };
 
@@ -96,10 +89,10 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             let
               oldPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
               newPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
               oldDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${oldPostgresql.psqlSchema}";
               newDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${newPostgresql.psqlSchema}";
             in
@@ -124,7 +117,8 @@ self.inputs.nixpkgs.lib.nixos.runTest {
       specialisation.orioledb17.configuration = {
         services.postgresql = {
           package = lib.mkForce (
-            postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17
+            postgresqlWithExtension
+              self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17
           );
           settings = {
             shared_preload_libraries = "orioledb";
@@ -155,7 +149,7 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             let
               newPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_orioledb-17;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_orioledb-17;
             in
             ''
               set -x
diff --git a/nix/ext/tests/pgsodium.nix b/nix/ext/tests/pgsodium.nix
index 00a2bf44f2..4d2962803e 100644
--- a/nix/ext/tests/pgsodium.nix
+++ b/nix/ext/tests/pgsodium.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,13 +12,14 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
           postgresql.lib
           (installedExtension majorVersion)
-          (self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${majorVersion}".exts.hypopg)
+          (self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${majorVersion}".exts.hypopg
+          )
         ];
         passthru = {
           inherit (postgresql) version psqlSchema;
@@ -28,7 +29,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -48,25 +49,16 @@ let
     ''
   );
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
-
       services.postgresql = {
         enable = true;
-        package = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+        package =
+          postgresqlWithExtension
+            self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
         settings = {
           "shared_preload_libraries" = pname;
           "pgsodium.getkey_script" = pgsodiumGetKey;
@@ -76,7 +68,7 @@ self.inputs.nixpkgs.lib.nixos.runTest {
       specialisation.postgresql17.configuration = {
         services.postgresql = {
           package = lib.mkForce (
-            postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17
+            postgresqlWithExtension self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17
           );
         };
 
@@ -93,10 +85,10 @@ self.inputs.nixpkgs.lib.nixos.runTest {
             let
               oldPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
               newPostgresql =
                 postgresqlWithExtension
-                  self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
               oldDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${oldPostgresql.psqlSchema}";
               newDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${newPostgresql.psqlSchema}";
             in
diff --git a/nix/ext/tests/plpgsql_check.nix b/nix/ext/tests/plpgsql_check.nix
index 3beac0c720..e4b381fee3 100644
--- a/nix/ext/tests/plpgsql_check.nix
+++ b/nix/ext/tests/plpgsql_check.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -41,24 +41,18 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
diff --git a/nix/ext/tests/plv8.nix b/nix/ext/tests/plv8.nix
index 91d7d29d13..381cbcae48 100644
--- a/nix/ext/tests/plv8.nix
+++ b/nix/ext/tests/plv8.nix
@@ -5,7 +5,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -13,7 +13,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -28,7 +28,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -42,30 +42,24 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
       services.openssh = {
         enable = true;
       };
 
       services.postgresql = {
         enable = true;
-        package = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+        package =
+          postgresqlWithExtension
+            self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
         authentication = ''
           local all postgres peer map=postgres
           local all all peer map=root
diff --git a/nix/ext/tests/postgis.nix b/nix/ext/tests/postgis.nix
new file mode 100644
index 0000000000..d7b8ccb3bd
--- /dev/null
+++ b/nix/ext/tests/postgis.nix
@@ -0,0 +1,158 @@
+{ self, pkgs }:
+let
+  pname = "postgis";
+  inherit (pkgs) lib;
+  installedExtension =
+    postgresMajorVersion:
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+      pname
+    }";
+  versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
+  postgresqlWithExtension =
+    postgresql:
+    let
+      majorVersion = lib.versions.major postgresql.version;
+      pkg = pkgs.pkgsLinux.buildEnv {
+        name = "postgresql-${majorVersion}-${pname}";
+        paths = [
+          postgresql
+          postgresql.lib
+          (installedExtension majorVersion)
+        ];
+        passthru = {
+          inherit (postgresql) version psqlSchema;
+          installedExtensions = [ (installedExtension majorVersion) ];
+          lib = pkg;
+          withPackages = _: pkg;
+          withJIT = pkg;
+          withoutJIT = pkg;
+        };
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
+        pathsToLink = [
+          "/"
+          "/bin"
+          "/lib"
+        ];
+        postBuild = ''
+          wrapProgram $out/bin/postgres --set NIX_PGLIBDIR $out/lib
+          wrapProgram $out/bin/pg_ctl --set NIX_PGLIBDIR $out/lib
+          wrapProgram $out/bin/pg_upgrade --set NIX_PGLIBDIR $out/lib
+        '';
+      };
+    in
+    pkg;
+in
+pkgs.testers.runNixOSTest {
+  name = pname;
+  nodes.server =
+    { config, ... }:
+    {
+      services.openssh = {
+        enable = true;
+      };
+
+      services.postgresql = {
+        enable = true;
+        package =
+          postgresqlWithExtension
+            self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+      };
+
+      specialisation.postgresql17.configuration = {
+        services.postgresql = {
+          package = lib.mkForce (
+            postgresqlWithExtension self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17
+          );
+        };
+
+        systemd.services.postgresql-migrate = {
+          serviceConfig = {
+            Type = "oneshot";
+            RemainAfterExit = true;
+            User = "postgres";
+            Group = "postgres";
+            StateDirectory = "postgresql";
+            WorkingDirectory = "${builtins.dirOf config.services.postgresql.dataDir}";
+          };
+          script =
+            let
+              oldPostgresql =
+                postgresqlWithExtension
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+              newPostgresql =
+                postgresqlWithExtension
+                  self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
+              oldDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${oldPostgresql.psqlSchema}";
+              newDataDir = "${builtins.dirOf config.services.postgresql.dataDir}/${newPostgresql.psqlSchema}";
+            in
+            ''
+              if [[ ! -d ${newDataDir} ]]; then
+                install -d -m 0700 -o postgres -g postgres "${newDataDir}"
+                ${newPostgresql}/bin/initdb -D "${newDataDir}"
+                ${newPostgresql}/bin/pg_upgrade --old-datadir "${oldDataDir}" --new-datadir "${newDataDir}" \
+                  --old-bindir "${oldPostgresql}/bin" --new-bindir "${newPostgresql}/bin"
+              else
+                echo "${newDataDir} already exists"
+              fi
+            '';
+        };
+
+        systemd.services.postgresql = {
+          after = [ "postgresql-migrate.service" ];
+          requires = [ "postgresql-migrate.service" ];
+        };
+      };
+    };
+  testScript =
+    { nodes, ... }:
+    let
+      pg17-configuration = "${nodes.server.system.build.toplevel}/specialisation/postgresql17";
+    in
+    ''
+      versions = {
+        "15": [${lib.concatStringsSep ", " (map (s: ''"${s}"'') (versions "15"))}],
+        "17": [${lib.concatStringsSep ", " (map (s: ''"${s}"'') (versions "17"))}],
+      }
+
+      def run_sql(query):
+        return server.succeed(f"""sudo -u postgres psql -t -A -F\",\" -c \"{query}\" """).strip()
+
+      def check_upgrade_path(pg_version):
+        with subtest("Check ${pname} upgrade path"):
+          firstVersion = versions[pg_version][0]
+          server.succeed("sudo -u postgres psql -c 'DROP EXTENSION IF EXISTS ${pname};'")
+          run_sql(f"""CREATE EXTENSION ${pname} WITH VERSION '{firstVersion}' CASCADE;""")
+          installed_version = run_sql(r"""SELECT extversion FROM pg_extension WHERE extname = '${pname}';""")
+          assert installed_version == firstVersion, f"Expected ${pname} version {firstVersion}, but found {installed_version}"
+          for version in versions[pg_version][1:]:
+            run_sql(f"""ALTER EXTENSION ${pname} UPDATE TO '{version}';""")
+            installed_version = run_sql(r"""SELECT extversion FROM pg_extension WHERE extname = '${pname}';""")
+            assert installed_version == version, f"Expected ${pname} version {version}, but found {installed_version}"
+
+      start_all()
+
+      server.wait_for_unit("multi-user.target")
+      server.wait_for_unit("postgresql.service")
+
+      check_upgrade_path("15")
+
+      with subtest("Check ${pname} latest extension version"):
+        server.succeed("sudo -u postgres psql -c 'DROP EXTENSION ${pname};'")
+        server.succeed("sudo -u postgres psql -c 'CREATE EXTENSION ${pname} CASCADE;'")
+        installed_extensions=run_sql(r"""SELECT extname, extversion FROM pg_extension where extname = '${pname}';""")
+        latestVersion = versions["15"][-1]
+        assert f"${pname},{latestVersion}" in installed_extensions, f"Expected ${pname} version {latestVersion}, but found {installed_extensions}"
+
+      with subtest("switch to postgresql 17"):
+        server.succeed(
+          "${pg17-configuration}/bin/switch-to-configuration test >&2"
+        )
+
+      with subtest("Check ${pname} latest extension version after upgrade"):
+        installed_extensions=run_sql(r"""SELECT extname, extversion FROM pg_extension;""")
+        latestVersion = versions["17"][-1]
+        assert f"${pname},{latestVersion}" in installed_extensions
+
+      check_upgrade_path("17")
+    '';
+}
diff --git a/nix/ext/tests/timescaledb.nix b/nix/ext/tests/timescaledb.nix
index a98d1f5ebe..285ad39ce1 100644
--- a/nix/ext/tests/timescaledb.nix
+++ b/nix/ext/tests/timescaledb.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = (installedExtension "15").versions;
@@ -12,7 +12,7 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
@@ -27,7 +27,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -41,17 +41,18 @@ let
       };
     in
     pkg;
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = "timescaledb";
-  hostPkgs = pkgs;
   nodes.server =
     { ... }:
     {
       services.postgresql = {
         enable = true;
-        package = (postgresqlWithExtension psql_15);
+        package = psql_15;
         authentication = ''
           local all postgres peer map=postgres
           local all all peer map=root
diff --git a/nix/ext/tests/vault.nix b/nix/ext/tests/vault.nix
index 42fafacabd..28ad6b6298 100644
--- a/nix/ext/tests/vault.nix
+++ b/nix/ext/tests/vault.nix
@@ -4,7 +4,7 @@ let
   inherit (pkgs) lib;
   installedExtension =
     postgresMajorVersion:
-    self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
+    self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${postgresMajorVersion}".exts."${
       pname
     }";
   versions = postgresqlMajorVersion: (installedExtension postgresqlMajorVersion).versions;
@@ -12,13 +12,14 @@ let
     postgresql:
     let
       majorVersion = lib.versions.major postgresql.version;
-      pkg = pkgs.buildEnv {
+      pkg = pkgs.pkgsLinux.buildEnv {
         name = "postgresql-${majorVersion}-${pname}";
         paths = [
           postgresql
           postgresql.lib
           (installedExtension majorVersion)
-          (self.legacyPackages.${pkgs.stdenv.hostPlatform.system}."psql_${majorVersion}".exts.pgsodium) # dependency
+          (self.legacyPackages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}."psql_${majorVersion}".exts.pgsodium
+          ) # dependency
         ];
         passthru = {
           inherit (postgresql) version psqlSchema;
@@ -28,7 +29,7 @@ let
           withJIT = pkg;
           withoutJIT = pkg;
         };
-        nativeBuildInputs = [ pkgs.makeWrapper ];
+        nativeBuildInputs = [ pkgs.pkgsLinux.makeWrapper ];
         pathsToLink = [
           "/"
           "/bin"
@@ -47,25 +48,18 @@ let
       echo 0000000000000000000000000000000000000000000000000000000000000000
     ''
   );
-  psql_15 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_15;
-  psql_17 = postgresqlWithExtension self.packages.${pkgs.stdenv.hostPlatform.system}.postgresql_17;
+  psql_15 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_15;
+  psql_17 =
+    postgresqlWithExtension
+      self.packages.${pkgs.pkgsLinux.stdenv.hostPlatform.system}.postgresql_17;
 in
-self.inputs.nixpkgs.lib.nixos.runTest {
+pkgs.testers.runNixOSTest {
   name = pname;
-  hostPkgs = pkgs;
   nodes.server =
     { config, ... }:
     {
-      virtualisation = {
-        forwardPorts = [
-          {
-            from = "host";
-            host.port = 13022;
-            guest.port = 22;
-          }
-        ];
-      };
-
       services.postgresql = {
         enable = true;
         package = psql_15;
diff --git a/nix/postgresql/generic.nix b/nix/postgresql/generic.nix
index a99ecad6d2..6eaf873aef 100644
--- a/nix/postgresql/generic.nix
+++ b/nix/postgresql/generic.nix
@@ -322,7 +322,7 @@ let
 
           tests = {
             postgresql-wal-receiver = import ../../../../nixos/tests/postgresql-wal-receiver.nix {
-              system = stdenv.hostPlatform.system;
+              inherit (stdenv.hostPlatform) system;
               pkgs = self;
               package = this;
             };
@@ -330,7 +330,7 @@ let
           }
           // lib.optionalAttrs jitSupport {
             postgresql-jit = import ../../../../nixos/tests/postgresql-jit.nix {
-              system = stdenv.hostPlatform.system;
+              inherit (stdenv.hostPlatform) system;
               pkgs = self;
               package = this;
             };
diff --git a/nix/tests/http-mock-server.py b/nix/tests/http-mock-server.py
index fedeb40ade..005c892f25 100644
--- a/nix/tests/http-mock-server.py
+++ b/nix/tests/http-mock-server.py
@@ -237,10 +237,16 @@ def run_server(port=None):
 
         port_file = os.environ.get("HTTP_MOCK_PORT_FILE", "/tmp/http-mock-port")
         try:
+            # Ensure directory exists (if any)
+            port_dir = os.path.dirname(port_file)
+            if port_dir:
+                os.makedirs(port_dir, exist_ok=True)
             with open(port_file, "w") as f:
                 f.write(str(port))
-        except:
-            pass  # Ignore if we can't write the port file
+            print(f"Port file written to {port_file}")
+        except Exception as e:
+            print(f"ERROR: Failed to write port file {port_file}: {e}")
+            raise  # Don't ignore port file write errors
 
         server.serve_forever()
     except OSError as e: