Add missing annotations

Author: sebastianbergmann

src/Framework/TestCase.php

@@ -343,6 +343,8 @@ protected function tearDown(): void
      * Returns a string representation of the test case.
      *
      * @throws Exception
+     *
+     * @internal This method is not covered by the backward compatibility promise for PHPUnit
      */
     public function toString(): string
     {
@@ -355,6 +357,9 @@ public function toString(): string
         return $buffer . $this->dataSetAsStringWithData();
     }
 
+    /**
+     * @internal This method is not covered by the backward compatibility promise for PHPUnit
+     */
     final public function count(): int
     {
         return 1;
@@ -417,6 +422,9 @@ final public function expectNotToPerformAssertions(): void
         $this->doesNotPerformAssertions = true;
     }
 
+    /**
+     * @internal This method is not covered by the backward compatibility promise for PHPUnit
+     */
     final public function status(): TestStatus
     {
         return $this->status;