diff --git a/tests/Unit/Client/Transport/HttpTransportTest.php b/tests/Unit/Client/Transport/HttpTransportTest.php
index 100107d2..408980d7 100644
--- a/tests/Unit/Client/Transport/HttpTransportTest.php
+++ b/tests/Unit/Client/Transport/HttpTransportTest.php
@@ -43,8 +43,8 @@ public function testSseBufferIsBoundedByConfiguredCap(): void
 
         $this->invokeProcessSseStream($transport);
 
-        self::assertSame('', $this->readPrivate($transport, 'sseBuffer'), 'buffer must be cleared on abort');
-        self::assertNull($this->readPrivate($transport, 'activeStream'), 'stream must be released on abort');
+        $this->assertSame('', $this->readPrivate($transport, 'sseBuffer'), 'buffer must be cleared on abort');
+        $this->assertNull($this->readPrivate($transport, 'activeStream'), 'stream must be released on abort');
     }
 
     #[TestDox('aborting the SSE stream fails the in-flight request immediately instead of waiting for its timeout')]
@@ -60,9 +60,9 @@ public function testAbortFailsPendingRequestFast(): void
         $this->invokeProcessSseStream($transport);
 
         $response = $state->consumeResponse(1);
-        self::assertInstanceOf(Error::class, $response);
-        self::assertSame(Error::INTERNAL_ERROR, $response->code);
-        self::assertSame(1, $response->id);
+        $this->assertInstanceOf(Error::class, $response);
+        $this->assertSame(Error::INTERNAL_ERROR, $response->code);
+        $this->assertSame(1, $response->id);
     }
 
     #[TestDox('well-formed delimited events are parsed and dispatched')]
@@ -78,7 +78,7 @@ public function testWellFormedEventsStillParse(): void
 
         $this->invokeProcessSseStream($transport);
 
-        self::assertSame(['hello', 'world'], $messages);
+        $this->assertSame(['hello', 'world'], $messages);
     }
 
     #[TestDox('the buffer cap must be a positive number of bytes')]
diff --git a/tests/Unit/Client/Transport/StdioTransportTest.php b/tests/Unit/Client/Transport/StdioTransportTest.php
index ecc46b8f..fb314083 100644
--- a/tests/Unit/Client/Transport/StdioTransportTest.php
+++ b/tests/Unit/Client/Transport/StdioTransportTest.php
@@ -33,7 +33,7 @@ public function testInputBufferIsBounded(): void
 
         $this->invokeProcessInput($transport);
 
-        self::assertSame('', $this->readPrivate($transport, 'inputBuffer'), 'buffer must be cleared on abort');
+        $this->assertSame('', $this->readPrivate($transport, 'inputBuffer'), 'buffer must be cleared on abort');
     }
 
     #[TestDox('aborting the input fails the in-flight request immediately')]
@@ -49,9 +49,9 @@ public function testAbortFailsPendingRequestFast(): void
         $this->invokeProcessInput($transport);
 
         $response = $state->consumeResponse(1);
-        self::assertInstanceOf(Error::class, $response);
-        self::assertSame(Error::INTERNAL_ERROR, $response->code);
-        self::assertSame(1, $response->id);
+        $this->assertInstanceOf(Error::class, $response);
+        $this->assertSame(Error::INTERNAL_ERROR, $response->code);
+        $this->assertSame(1, $response->id);
     }
 
     #[TestDox('newline-delimited frames within the cap are parsed and dispatched')]
@@ -67,7 +67,7 @@ public function testWellFormedFramesStillParse(): void
 
         $this->invokeProcessInput($transport);
 
-        self::assertSame(['{"a":1}', '{"b":2}'], $messages);
+        $this->assertSame(['{"a":1}', '{"b":2}'], $messages);
     }
 
     #[TestDox('the buffer cap must be a positive number of bytes')]
diff --git a/tests/Unit/Server/Transport/StdioTransportTest.php b/tests/Unit/Server/Transport/StdioTransportTest.php
index 252454d8..dbfcec2f 100644
--- a/tests/Unit/Server/Transport/StdioTransportTest.php
+++ b/tests/Unit/Server/Transport/StdioTransportTest.php
@@ -26,7 +26,7 @@ public function testOverlongLineIsDiscarded(): void
 
         $this->pumpToEof($transport);
 
-        self::assertSame([], $messages, 'the over-length line must never be dispatched');
+        $this->assertSame([], $messages, 'the over-length line must never be dispatched');
     }
 
     #[TestDox('processing resumes with the next line after an over-length line is discarded')]
@@ -37,7 +37,7 @@ public function testRecoversAfterOverlongLine(): void
 
         $this->pumpToEof($transport);
 
-        self::assertSame(['{"valid":1}'], $messages);
+        $this->assertSame(['{"valid":1}'], $messages);
     }
 
     #[TestDox('a normal line within the cap is dispatched')]
@@ -48,7 +48,7 @@ public function testNormalLineIsDispatched(): void
 
         $this->pumpToEof($transport);
 
-        self::assertSame(['{"jsonrpc":"2.0","id":1}'], $messages);
+        $this->assertSame(['{"jsonrpc":"2.0","id":1}'], $messages);
     }
 
     #[TestDox('the line byte cap must be a positive number of bytes')]