diff --git a/tests/cases/Conf/TestConf.php b/tests/cases/Conf/TestConf.php
index edfcfbb..73bec5f 100644
--- a/tests/cases/Conf/TestConf.php
+++ b/tests/cases/Conf/TestConf.php
@@ -39,20 +39,20 @@ class TestConf extends \JKingWeb\Arsse\Test\AbstractTest {
     }
 
     public function testLoadDefaultValues() {
-        $this->assertInstanceOf(Conf::class, new Conf());
+        $this->assertInstanceOf(Conf::class, new Conf);
     }
 
     /** @depends testLoadDefaultValues */
     public function testImportFromArray() {
         $arr = ['lang' => "xx"];
-        $conf = new Conf();
+        $conf = new Conf;
         $conf->import($arr);
         $this->assertEquals("xx", $conf->lang);
     }
 
     /** @depends testImportFromArray */
     public function testImportFromFile() {
-        $conf = new Conf();
+        $conf = new Conf;
         $conf->importFile(self::$path."confGood");
         $this->assertEquals("xx", $conf->lang);
         $conf = new Conf(self::$path."confGood");
@@ -97,7 +97,7 @@ class TestConf extends \JKingWeb\Arsse\Test\AbstractTest {
     }
 
     public function testExportToArray() {
-        $conf = new Conf();
+        $conf = new Conf;
         $conf->lang = ["en", "fr"]; // should not be exported: not scalar
         $conf->dbSQLite3File = "test.db"; // should be exported: value changed
         $conf->userDriver = null; // should be exported: changed value, even when null
@@ -116,7 +116,7 @@ class TestConf extends \JKingWeb\Arsse\Test\AbstractTest {
     /** @depends testExportToArray
      * @depends testImportFromFile */
     public function testExportToFile() {
-        $conf = new Conf();
+        $conf = new Conf;
         $conf->lang = ["en", "fr"]; // should not be exported: not scalar
         $conf->dbSQLite3File = "test.db"; // should be exported: value changed
         $conf->userDriver = null; // should be exported: changed value, even when null
diff --git a/tests/cases/Db/SQLite3/TestCreation.php b/tests/cases/Db/SQLite3/TestCreation.php
index 4f04918..f9ac55b 100644
--- a/tests/cases/Db/SQLite3/TestCreation.php
+++ b/tests/cases/Db/SQLite3/TestCreation.php
@@ -107,8 +107,7 @@ class TestCreation extends \JKingWeb\Arsse\Test\AbstractTest {
         chmod($path."Awal/arsse.db-wal", 0111);
         chmod($path."Ashm/arsse.db-shm", 0111);
         // set up configuration
-        Arsse::$conf = new Conf();
-        Arsse::$conf->dbSQLite3File = ":memory:";
+        $this->setConf(['dbSQLite3File' => ":memory:"]);
     }
 
     public function tearDown() {
diff --git a/tests/cases/Db/SQLite3/TestDriver.php b/tests/cases/Db/SQLite3/TestDriver.php
index 6453326..835ad09 100644
--- a/tests/cases/Db/SQLite3/TestDriver.php
+++ b/tests/cases/Db/SQLite3/TestDriver.php
@@ -26,11 +26,11 @@ class TestDriver extends \JKingWeb\Arsse\Test\AbstractTest {
             $this->markTestSkipped("SQLite extension not loaded");
         }
         $this->clearData();
-        $conf = new Conf();
-        Arsse::$conf = $conf;
-        $conf->dbDriver = Driver::class;
-        $conf->dbSQLite3Timeout = 0;
-        $conf->dbSQLite3File = tempnam(sys_get_temp_dir(), 'ook');
+        $this->setConf([
+            'dbDriver' => Driver::class,
+            'dbSQLite3Timeout' => 0,
+            'dbSQLite3File' => tempnam(sys_get_temp_dir(), 'ook'),
+        ]);
         $this->drv = new Driver();
         $this->ch = new \SQLite3(Arsse::$conf->dbSQLite3File);
         $this->ch->enableExceptions(true);
diff --git a/tests/cases/Db/SQLite3/TestUpdate.php b/tests/cases/Db/SQLite3/TestUpdate.php
index d6c8fc3..2ff02e8 100644
--- a/tests/cases/Db/SQLite3/TestUpdate.php
+++ b/tests/cases/Db/SQLite3/TestUpdate.php
@@ -31,9 +31,7 @@ class TestUpdate extends \JKingWeb\Arsse\Test\AbstractTest {
         }
         $this->clearData();
         $this->vfs = vfsStream::setup("schemata", null, ['SQLite3' => []]);
-        if (!$conf) {
-            $conf = new Conf();
-        }
+        $conf = $conf ?? new Conf;
         $conf->dbDriver = Driver::class;
         $conf->dbSQLite3File = ":memory:";
         Arsse::$conf = $conf;
@@ -111,7 +109,7 @@ class TestUpdate extends \JKingWeb\Arsse\Test\AbstractTest {
 
     public function testDeclineManualUpdate() {
         // turn auto-updating off
-        $conf = new Conf();
+        $conf = new Conf;
         $conf->dbAutoUpdate = false;
         $this->setUp($conf);
         $this->assertException("updateManual", "Db");
diff --git a/tests/cases/Db/SQLite3PDO/TestCreation.php b/tests/cases/Db/SQLite3PDO/TestCreation.php
index 34cb824..4f2e1a2 100644
--- a/tests/cases/Db/SQLite3PDO/TestCreation.php
+++ b/tests/cases/Db/SQLite3PDO/TestCreation.php
@@ -108,8 +108,7 @@ class TestCreation extends \JKingWeb\Arsse\Test\AbstractTest {
         chmod($path."Awal/arsse.db-wal", 0111);
         chmod($path."Ashm/arsse.db-shm", 0111);
         // set up configuration
-        Arsse::$conf = new Conf();
-        Arsse::$conf->dbSQLite3File = ":memory:";
+        $this->setConf(['dbSQLite3File' => ":memory:"]);
     }
 
     public function tearDown() {
diff --git a/tests/cases/Db/SQLite3PDO/TestDriver.php b/tests/cases/Db/SQLite3PDO/TestDriver.php
index 1fec09c..6d58f51 100644
--- a/tests/cases/Db/SQLite3PDO/TestDriver.php
+++ b/tests/cases/Db/SQLite3PDO/TestDriver.php
@@ -27,11 +27,11 @@ class TestDriver extends \JKingWeb\Arsse\Test\AbstractTest {
             $this->markTestSkipped("PDO-SQLite extension not loaded");
         }
         $this->clearData();
-        $conf = new Conf();
-        Arsse::$conf = $conf;
-        $conf->dbDriver = PDODriver::class;
-        $conf->dbSQLite3Timeout = 0;
-        $conf->dbSQLite3File = tempnam(sys_get_temp_dir(), 'ook');
+        $this->setConf([
+            'dbDriver' => PDODriver::class,
+            'dbSQLite3Timeout' => 0,
+            'dbSQLite3File' => tempnam(sys_get_temp_dir(), 'ook'),
+        ]);
         $this->drv = new PDODriver();
         $this->ch = new \PDO("sqlite:".Arsse::$conf->dbSQLite3File, "", "", [\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION]);
     }
diff --git a/tests/cases/Feed/TestFeed.php b/tests/cases/Feed/TestFeed.php
index fde0195..a1ca84b 100644
--- a/tests/cases/Feed/TestFeed.php
+++ b/tests/cases/Feed/TestFeed.php
@@ -96,7 +96,7 @@ class TestFeed extends \JKingWeb\Arsse\Test\AbstractTest {
         }
         $this->base = self::$host."Feed/";
         $this->clearData();
-        Arsse::$conf = new Conf();
+        $this->setConf();
         Arsse::$db = Phake::mock(Database::class);
     }
 
diff --git a/tests/cases/Feed/TestFetching.php b/tests/cases/Feed/TestFetching.php
index afe1391..25d4d7c 100644
--- a/tests/cases/Feed/TestFetching.php
+++ b/tests/cases/Feed/TestFetching.php
@@ -26,7 +26,7 @@ class TestFetching extends \JKingWeb\Arsse\Test\AbstractTest {
         }
         $this->base = self::$host."Feed/";
         $this->clearData();
-        Arsse::$conf = new Conf();
+        $this->setConf();
     }
 
     public function testHandle400() {
diff --git a/tests/cases/REST/NextCloudNews/TestV1_2.php b/tests/cases/REST/NextCloudNews/TestV1_2.php
index 2ee0b1b..d3a9a9b 100644
--- a/tests/cases/REST/NextCloudNews/TestV1_2.php
+++ b/tests/cases/REST/NextCloudNews/TestV1_2.php
@@ -340,7 +340,7 @@ class TestV1_2 extends \JKingWeb\Arsse\Test\AbstractTest {
 
     public function setUp() {
         $this->clearData();
-        Arsse::$conf = new Conf();
+        $this->setConf();
         // create a mock user manager
         Arsse::$user = Phake::mock(User::class);
         Phake::when(Arsse::$user)->auth->thenReturn(true);
diff --git a/tests/cases/REST/TinyTinyRSS/TestAPI.php b/tests/cases/REST/TinyTinyRSS/TestAPI.php
index 9aea12e..62ba256 100644
--- a/tests/cases/REST/TinyTinyRSS/TestAPI.php
+++ b/tests/cases/REST/TinyTinyRSS/TestAPI.php
@@ -177,7 +177,7 @@ LONG_STRING;
 
     public function setUp() {
         $this->clearData();
-        Arsse::$conf = new Conf();
+        $this->setConf();
         // create a mock user manager
         Arsse::$user = Phake::mock(User::class);
         Phake::when(Arsse::$user)->auth->thenReturn(true);
@@ -226,7 +226,7 @@ LONG_STRING;
     /** @dataProvider provideLoginRequests */
     public function testLogIn(array $conf, $httpUser, array $data, $sessions) {
         Arsse::$user->id = null;
-        Arsse::$conf = (new Conf)->import($conf);
+        $this->setConf($conf);
         Phake::when(Arsse::$user)->auth->thenReturn(false);
         Phake::when(Arsse::$user)->auth("john.doe@example.com", "secret")->thenReturn(true);
         Phake::when(Arsse::$user)->auth("jane.doe@example.com", "superman")->thenReturn(true);
@@ -260,7 +260,7 @@ LONG_STRING;
     /** @dataProvider provideResumeRequests */
     public function testValidateASession(array $conf, $httpUser, string $data, $result) {
         Arsse::$user->id = null;
-        Arsse::$conf = (new Conf)->import($conf);
+        $this->setConf($conf);
         Phake::when(Arsse::$db)->sessionResume("PriestsOfSyrinx")->thenReturn([
             'id' => "PriestsOfSyrinx",
             'created' => "2000-01-01 00:00:00",
diff --git a/tests/cases/REST/TinyTinyRSS/TestIcon.php b/tests/cases/REST/TinyTinyRSS/TestIcon.php
index cb74f67..53db57c 100644
--- a/tests/cases/REST/TinyTinyRSS/TestIcon.php
+++ b/tests/cases/REST/TinyTinyRSS/TestIcon.php
@@ -24,7 +24,7 @@ class TestIcon extends \JKingWeb\Arsse\Test\AbstractTest {
 
     public function setUp() {
         $this->clearData();
-        Arsse::$conf = new Conf();
+        $this->setConf();
         // create a mock user manager
         Arsse::$user = Phake::mock(User::class);
         // create a mock database interface
@@ -108,7 +108,7 @@ class TestIcon extends \JKingWeb\Arsse\Test\AbstractTest {
         $this->assertMessage($exp, $this->reqAuthFailed("42.ico"));
         $this->assertMessage($exp, $this->reqAuthFailed("1337.ico"));
         // with HTTP auth required, only authenticated requests should succeed
-        Arsse::$conf = (new Conf())->import(['userHTTPAuthRequired' => true]);
+        $this->setConf(['userHTTPAuthRequired' => true]);
         $exp = new Response(301, ['Location' => "http://example.org/icon.gif"]);
         $this->assertMessage($exp, $this->reqAuth("42.ico"));
         $this->assertMessage($exp, $this->reqAuth("1337.ico"));
diff --git a/tests/cases/Service/TestService.php b/tests/cases/Service/TestService.php
index 1ec4a3d..3ba18e0 100644
--- a/tests/cases/Service/TestService.php
+++ b/tests/cases/Service/TestService.php
@@ -19,7 +19,7 @@ class TestService extends \JKingWeb\Arsse\Test\AbstractTest {
 
     public function setUp() {
         $this->clearData();
-        Arsse::$conf = new Conf();
+        $this->setConf();
         Arsse::$db = Phake::mock(Database::class);
         $this->srv = new Service();
     }
diff --git a/tests/lib/Database/Setup.php b/tests/lib/Database/Setup.php
index c9b982f..0a98edf 100644
--- a/tests/lib/Database/Setup.php
+++ b/tests/lib/Database/Setup.php
@@ -22,8 +22,7 @@ trait Setup {
     public function setUp() {
         // establish a clean baseline
         $this->clearData();
-        // create a default configuration
-        Arsse::$conf = new Conf();
+        $this->setConf();
         // configure and create the relevant database driver
         $this->setUpDriver();
         // create the database interface with the suitable driver