Add shouldImplement and related missing tests

rules-tests/Rector/Class_/PromisesToAssertsRector/Fixture/should_be_instance_of.php.inc

@@ -0,0 +1,61 @@
+<?php
+
+namespace spec\Rector\PhpSpecToPHPUnit;
+
+use PhpSpec\ObjectBehavior;
+
+class TestClassMethod extends ObjectBehavior
+{
+    public function let_1()
+    {
+        $this->shouldBeAnInstanceOf(\stdClass::class);
+    }
+
+    public function let_2()
+    {
+        $this->shouldHaveType(\stdClass::class);
+    }
+
+    public function let_3()
+    {
+        $this->shouldReturnAnInstanceOf(\stdClass::class);
+    }
+
+    public function let_4()
+    {
+        $this->shouldImplement(\stdClass::class);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace spec\Rector\PhpSpecToPHPUnit;
+
+use PhpSpec\ObjectBehavior;
+
+class TestClassMethod extends ObjectBehavior
+{
+    public function let_1()
+    {
+        $this->assertInstanceOf(\stdClass::class, $this->testClassMethod);
+    }
+
+    public function let_2()
+    {
+        $this->assertInstanceOf(\stdClass::class, $this->testClassMethod);
+    }
+
+    public function let_3()
+    {
+        $this->assertInstanceOf(\stdClass::class, $this->testClassMethod);
+    }
+
+    public function let_4()
+    {
+        $this->assertInstanceOf(\stdClass::class, $this->testClassMethod);
+    }
+}
+
+?>

src/Enum/ProphecyPromisesToPHPUnitAssertMap.php

@@ -13,7 +13,7 @@ final class ProphecyPromisesToPHPUnitAssertMap
      * @var array<string, string[]>
      */
     public const PROMISES_BY_ASSERT_METHOD = [
-        'assertInstanceOf' => ['shouldBeAnInstanceOf', 'shouldHaveType', 'shouldReturnAnInstanceOf'],
+        'assertInstanceOf' => ['shouldBeAnInstanceOf', 'shouldHaveType', 'shouldReturnAnInstanceOf', 'shouldImplement'],
         'assertSame' => ['shouldBe', 'shouldReturn'],
         'assertNotSame' => ['shouldNotBe', 'shouldNotReturn'],
         'assertCount' => ['shouldHaveCount'],