postgresql: remove thisAttr argument by calling tests directly

Previously, it was not possible to run tests on an overridden derivation, because
the derivation under test was always pulled from pkgs.

With this change, the following will return the same test:

postgresql_jit.tests

and

(postgresql.override { jitSupport = true; }).tests

nixos/tests/postgresql-jit.nix

···
 { system ? builtins.currentSystem
 , config ? {}
 , pkgs ? import ../.. { inherit system config; }
+, package ? null
 }:
 
 with import ../lib/testing-python.nix { inherit system pkgs; };
···
   inherit (pkgs) lib;
   packages = builtins.attrNames (import ../../pkgs/servers/sql/postgresql pkgs);
 
-  mkJitTest = packageName: makeTest {
-    name = "${packageName}";
+  mkJitTestFromName = name:
+    mkJitTest pkgs.${name};
+
+  mkJitTest = package: makeTest {
+    name = package.name;
     meta.maintainers = with lib.maintainers; [ ma27 ];
     nodes.machine = { pkgs, lib, ... }: {
       services.postgresql = {
+        inherit package;
         enable = true;
         enableJIT = true;
-        package = pkgs.${packageName};
         initialScript = pkgs.writeText "init.sql" ''
           create table demo (id int);
           insert into demo (id) select generate_series(1, 5);
···
     '';
   };
 in
-lib.genAttrs packages mkJitTest
+if package == null then
+  lib.genAttrs packages mkJitTestFromName
+else
+  mkJitTest package

nixos/tests/postgresql-wal-receiver.nix

···
 { system ? builtins.currentSystem,
   config ? {},
-  pkgs ? import ../.. { inherit system config; }
+  pkgs ? import ../.. { inherit system config; },
+  package ? null
 }:
 
 with import ../lib/testing-python.nix { inherit system pkgs; };
···
   lib = pkgs.lib;
 
   # Makes a test for a PostgreSQL package, given by name and looked up from `pkgs`.
-  makePostgresqlWalReceiverTest = postgresqlPackage:
+  makeTestAttribute = name:
   {
-    name = postgresqlPackage;
-    value =
-      let
-        pkg = pkgs."${postgresqlPackage}";
-        postgresqlDataDir = "/var/lib/postgresql/${pkg.psqlSchema}";
-        replicationUser = "wal_receiver_user";
-        replicationSlot = "wal_receiver_slot";
-        replicationConn = "postgresql://${replicationUser}@localhost";
-        baseBackupDir = "/tmp/pg_basebackup";
-        walBackupDir = "/tmp/pg_wal";
-        atLeast12 = lib.versionAtLeast pkg.version "12.0";
+    inherit name;
+    value = makePostgresqlWalReceiverTest pkgs."${name}";
+  };
 
-        recoveryFile = if atLeast12
-            then pkgs.writeTextDir "recovery.signal" ""
-            else pkgs.writeTextDir "recovery.conf" "restore_command = 'cp ${walBackupDir}/%f %p'";
+  makePostgresqlWalReceiverTest = pkg:
+    let
+      postgresqlDataDir = "/var/lib/postgresql/${pkg.psqlSchema}";
+      replicationUser = "wal_receiver_user";
+      replicationSlot = "wal_receiver_slot";
+      replicationConn = "postgresql://${replicationUser}@localhost";
+      baseBackupDir = "/tmp/pg_basebackup";
+      walBackupDir = "/tmp/pg_wal";
+      atLeast12 = lib.versionAtLeast pkg.version "12.0";
 
-      in makeTest {
-        name = "postgresql-wal-receiver-${postgresqlPackage}";
-        meta.maintainers = with lib.maintainers; [ pacien ];
+      recoveryFile = if atLeast12
+          then pkgs.writeTextDir "recovery.signal" ""
+          else pkgs.writeTextDir "recovery.conf" "restore_command = 'cp ${walBackupDir}/%f %p'";
 
-        nodes.machine = { ... }: {
-          services.postgresql = {
-            package = pkg;
-            enable = true;
-            settings = lib.mkMerge [
-              {
-                wal_level = "archive"; # alias for replica on pg >= 9.6
-                max_wal_senders = 10;
-                max_replication_slots = 10;
-              }
-              (lib.mkIf atLeast12 {
-                restore_command = "cp ${walBackupDir}/%f %p";
-                recovery_end_command = "touch recovery.done";
-              })
-            ];
-            authentication = ''
-              host replication ${replicationUser} all trust
-            '';
-            initialScript = pkgs.writeText "init.sql" ''
-              create user ${replicationUser} replication;
-              select * from pg_create_physical_replication_slot('${replicationSlot}');
-            '';
-          };
+    in makeTest {
+      name = "postgresql-wal-receiver-${pkg.name}";
+      meta.maintainers = with lib.maintainers; [ pacien ];
+
+      nodes.machine = { ... }: {
+        services.postgresql = {
+          package = pkg;
+          enable = true;
+          settings = lib.mkMerge [
+            {
+              wal_level = "archive"; # alias for replica on pg >= 9.6
+              max_wal_senders = 10;
+              max_replication_slots = 10;
+            }
+            (lib.mkIf atLeast12 {
+              restore_command = "cp ${walBackupDir}/%f %p";
+              recovery_end_command = "touch recovery.done";
+            })
+          ];
+          authentication = ''
+            host replication ${replicationUser} all trust
+          '';
+          initialScript = pkgs.writeText "init.sql" ''
+            create user ${replicationUser} replication;
+            select * from pg_create_physical_replication_slot('${replicationSlot}');
+          '';
+        };
 
-          services.postgresqlWalReceiver.receivers.main = {
-            postgresqlPackage = pkg;
-            connection = replicationConn;
-            slot = replicationSlot;
-            directory = walBackupDir;
-          };
-          # This is only to speedup test, it isn't time racing. Service is set to autorestart always,
-          # default 60sec is fine for real system, but is too much for a test
-          systemd.services.postgresql-wal-receiver-main.serviceConfig.RestartSec = lib.mkForce 5;
+        services.postgresqlWalReceiver.receivers.main = {
+          postgresqlPackage = pkg;
+          connection = replicationConn;
+          slot = replicationSlot;
+          directory = walBackupDir;
         };
+        # This is only to speedup test, it isn't time racing. Service is set to autorestart always,
+        # default 60sec is fine for real system, but is too much for a test
+        systemd.services.postgresql-wal-receiver-main.serviceConfig.RestartSec = lib.mkForce 5;
+      };
 
-        testScript = ''
-          # make an initial base backup
-          machine.wait_for_unit("postgresql")
-          machine.wait_for_unit("postgresql-wal-receiver-main")
-          # WAL receiver healthchecks PG every 5 seconds, so let's be sure they have connected each other
-          # required only for 9.4
-          machine.sleep(5)
-          machine.succeed(
-              "${pkg}/bin/pg_basebackup --dbname=${replicationConn} --pgdata=${baseBackupDir}"
-          )
+      testScript = ''
+        # make an initial base backup
+        machine.wait_for_unit("postgresql")
+        machine.wait_for_unit("postgresql-wal-receiver-main")
+        # WAL receiver healthchecks PG every 5 seconds, so let's be sure they have connected each other
+        # required only for 9.4
+        machine.sleep(5)
+        machine.succeed(
+            "${pkg}/bin/pg_basebackup --dbname=${replicationConn} --pgdata=${baseBackupDir}"
+        )
 
-          # create a dummy table with 100 records
-          machine.succeed(
-              "sudo -u postgres psql --command='create table dummy as select * from generate_series(1, 100) as val;'"
-          )
+        # create a dummy table with 100 records
+        machine.succeed(
+            "sudo -u postgres psql --command='create table dummy as select * from generate_series(1, 100) as val;'"
+        )
 
-          # stop postgres and destroy data
-          machine.systemctl("stop postgresql")
-          machine.systemctl("stop postgresql-wal-receiver-main")
-          machine.succeed("rm -r ${postgresqlDataDir}/{base,global,pg_*}")
+        # stop postgres and destroy data
+        machine.systemctl("stop postgresql")
+        machine.systemctl("stop postgresql-wal-receiver-main")
+        machine.succeed("rm -r ${postgresqlDataDir}/{base,global,pg_*}")
 
-          # restore the base backup
-          machine.succeed(
-              "cp -r ${baseBackupDir}/* ${postgresqlDataDir} && chown postgres:postgres -R ${postgresqlDataDir}"
-          )
+        # restore the base backup
+        machine.succeed(
+            "cp -r ${baseBackupDir}/* ${postgresqlDataDir} && chown postgres:postgres -R ${postgresqlDataDir}"
+        )
 
-          # prepare WAL and recovery
-          machine.succeed("chmod a+rX -R ${walBackupDir}")
-          machine.execute(
-              "for part in ${walBackupDir}/*.partial; do mv $part ''${part%%.*}; done"
-          )  # make use of partial segments too
-          machine.succeed(
-              "cp ${recoveryFile}/* ${postgresqlDataDir}/ && chmod 666 ${postgresqlDataDir}/recovery*"
-          )
+        # prepare WAL and recovery
+        machine.succeed("chmod a+rX -R ${walBackupDir}")
+        machine.execute(
+            "for part in ${walBackupDir}/*.partial; do mv $part ''${part%%.*}; done"
+        )  # make use of partial segments too
+        machine.succeed(
+            "cp ${recoveryFile}/* ${postgresqlDataDir}/ && chmod 666 ${postgresqlDataDir}/recovery*"
+        )
 
-          # replay WAL
-          machine.systemctl("start postgresql")
-          machine.wait_for_file("${postgresqlDataDir}/recovery.done")
-          machine.systemctl("restart postgresql")
-          machine.wait_for_unit("postgresql")
+        # replay WAL
+        machine.systemctl("start postgresql")
+        machine.wait_for_file("${postgresqlDataDir}/recovery.done")
+        machine.systemctl("restart postgresql")
+        machine.wait_for_unit("postgresql")
 
-          # check that our records have been restored
-          machine.succeed(
-              "test $(sudo -u postgres psql --pset='pager=off' --tuples-only --command='select count(distinct val) from dummy;') -eq 100"
-          )
-        '';
-      };
+        # check that our records have been restored
+        machine.succeed(
+            "test $(sudo -u postgres psql --pset='pager=off' --tuples-only --command='select count(distinct val) from dummy;') -eq 100"
+        )
+      '';
     };
 
-# Maps the generic function over all attributes of PostgreSQL packages
-in builtins.listToAttrs (map makePostgresqlWalReceiverTest (builtins.attrNames (import ../../pkgs/servers/sql/postgresql pkgs)))
+in
+if package == null then
+  # all-tests.nix: Maps the generic function over all attributes of PostgreSQL packages
+  builtins.listToAttrs (map makeTestAttribute (builtins.attrNames (import ../../pkgs/servers/sql/postgresql pkgs)))
+else
+  # Called directly from <package>.tests
+  makePostgresqlWalReceiverTest package

pkgs/servers/sql/postgresql/default.nix

···
       in
       self.lib.nameValuePair attrName (import path {
         inherit jitSupport self;
-        thisAttr = attrName;
       })
     ) versions;
 

pkgs/servers/sql/postgresql/generic.nix

···
       , version, hash, muslPatches
 
       # for tests
-      , testers, nixosTests, thisAttr
+      , testers, nixosTests
 
       # JIT
       , jitSupport
···
                      this.pkgs;
 
       tests = {
-        postgresql = nixosTests.postgresql-wal-receiver.${thisAttr};
+        postgresql-wal-receiver = import ../../../../nixos/tests/postgresql-wal-receiver.nix {
+          inherit (stdenv) system;
+          pkgs = self;
+          package = this;
+        };
         pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;
       } // lib.optionalAttrs jitSupport {
-        postgresql-jit = nixosTests.postgresql-jit.${thisAttr};
+        postgresql-jit = import ../../../../nixos/tests/postgresql-jit.nix {
+          inherit (stdenv) system;
+          pkgs = self;
+          package = this;
+        };
       };
     };