diff --git a/.travis.yml b/.travis.yml
index 46ac9a0..2e19896 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,12 +3,9 @@ language: php
 sudo: false
 
 php:
-    - 5.3
-    - 5.4
-    - 5.5
-    - 5.6
-    - hhvm
+    - 7.3
+    - 7.4
 
 install: composer install
 
-script: phpunit --coverage-text
+script: ./vendor/bin/phpunit --coverage-text
diff --git a/ProphecyTestCase.php b/ProphecyTestCase.php
index 2229677..4e21da5 100644
--- a/ProphecyTestCase.php
+++ b/ProphecyTestCase.php
@@ -1,51 +1,64 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Prophecy\PhpUnit;
 
+use PHPUnit\Framework\AssertionFailedError;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Exception\Doubler\DoubleException;
+use Prophecy\Exception\Doubler\InterfaceNotFoundException;
 use Prophecy\Exception\Prediction\PredictionException;
+use Prophecy\Prophecy\MethodProphecy;
+use Prophecy\Prophecy\ObjectProphecy;
 use Prophecy\Prophet;
 
-abstract class ProphecyTestCase extends \PHPUnit_Framework_TestCase
+abstract class ProphecyTestCase extends TestCase
 {
     /**
      * @var Prophet|null
      */
     private $prophet;
 
+    /**
+     * @var bool
+     */
     private $prophecyAssertionsCounted = false;
 
     /**
-     * @param string|null $classOrInterface
+     * @throws DoubleException
+     * @throws InterfaceNotFoundException
      *
-     * @return \Prophecy\Prophecy\ObjectProphecy
+     * @psalm-param class-string|null $type
      */
-    protected function prophesize($classOrInterface = null)
+    protected function prophesize(?string $classOrInterface = null): ObjectProphecy
     {
+        if (\is_string($classOrInterface)) {
+            $this->recordDoubledType($classOrInterface);
+        }
+
         return $this->getProphet()->prophesize($classOrInterface);
     }
 
-    protected function verifyMockObjects()
+    protected function verifyMockObjects(): void
     {
         parent::verifyMockObjects();
 
-        if (null === $this->prophet) {
+        if ($this->prophet === null) {
             return;
         }
 
         try {
             $this->prophet->checkPredictions();
-        } catch (\Exception $e) {
-            /** Intentionally left empty */
-        }
-
-        $this->countProphecyAssertions();
-
-        if (isset($e)) {
-            throw $e;
+        } catch (PredictionException $e) {
+            throw new AssertionFailedError($e->getMessage());
+        } finally {
+            $this->countProphecyAssertions();
         }
     }
 
-    protected function tearDown()
+    /**
+     * @after
+     */
+    protected function prophecyTearDown(): void
     {
         if (null !== $this->prophet && !$this->prophecyAssertionsCounted) {
             // Some Prophecy assertions may have been done in tests themselves even when a failure happened before checking mock objects.
@@ -55,37 +68,27 @@ protected function tearDown()
         $this->prophet = null;
     }
 
-    protected function onNotSuccessfulTest(\Exception $e)
-    {
-        if ($e instanceof PredictionException) {
-            $e = new \PHPUnit_Framework_AssertionFailedError($e->getMessage(), $e->getCode(), $e);
-        }
-
-        return parent::onNotSuccessfulTest($e);
-    }
-
-    /**
-     * @return Prophet
-     */
-    private function getProphet()
-    {
-        if (null === $this->prophet) {
-            $this->prophet = new Prophet();
-        }
-
-        return $this->prophet;
-    }
-
-    private function countProphecyAssertions()
+    private function countProphecyAssertions(): void
     {
         $this->prophecyAssertionsCounted = true;
 
         foreach ($this->prophet->getProphecies() as $objectProphecy) {
             foreach ($objectProphecy->getMethodProphecies() as $methodProphecies) {
                 foreach ($methodProphecies as $methodProphecy) {
-                    $this->addToAssertionCount(count($methodProphecy->getCheckedPredictions()));
+                    \assert($methodProphecy instanceof MethodProphecy);
+
+                    $this->addToAssertionCount(\count($methodProphecy->getCheckedPredictions()));
                 }
             }
         }
     }
+
+    private function getProphet(): Prophet
+    {
+        if ($this->prophet === null) {
+            $this->prophet = new Prophet;
+        }
+
+        return $this->prophet;
+    }
 }
diff --git a/Tests/ProphecyTestCaseTest.php b/Tests/ProphecyTestCaseTest.php
index 0750d16..74b0d6e 100644
--- a/Tests/ProphecyTestCaseTest.php
+++ b/Tests/ProphecyTestCaseTest.php
@@ -1,63 +1,71 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Prophecy\PhpUnit\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Prophecy\PhpUnit\Tests\Fixtures\Error;
 use Prophecy\PhpUnit\Tests\Fixtures\MockFailure;
 use Prophecy\PhpUnit\Tests\Fixtures\SpyFailure;
 use Prophecy\PhpUnit\Tests\Fixtures\Success;
 
-class ProphecyTestCaseTest extends \PHPUnit_Framework_TestCase
+/**
+ * @covers \Prophecy\PhpUnit\ProphecyTestCase
+ */
+final class ProphecyTestCaseTest extends TestCase
 {
-    protected function setUp()
+    protected function setUp(): void
     {
-        // Define the constant because our tests are running PHPUnit testcases themselves
-        if (!defined('PHPUNIT_TESTSUITE')) {
-            define('PHPUNIT_TESTSUITE', true);
+        // Define the constant because our tests are running PHPUnit test cases themselves
+        if (!\defined('PHPUNIT_TESTSUITE')) {
+            \define('PHPUNIT_TESTSUITE', true);
         }
     }
 
-    public function testSuccess()
+    public function testSuccess(): void
     {
         $test = new Success('testMethod');
+
         $result = $test->run();
 
-        $this->assertEquals(0, $result->errorCount());
-        $this->assertEquals(0, $result->failureCount());
+        $this->assertSame(0, $result->errorCount());
+        $this->assertSame(0, $result->failureCount());
         $this->assertCount(1, $result);
-        $this->assertEquals(1, $test->getNumAssertions());
+        $this->assertSame(1, $test->getNumAssertions());
     }
 
-    public function testSpyPredictionFailure()
+    public function testSpyPredictionFailure(): void
     {
         $test = new SpyFailure('testMethod');
+
         $result = $test->run();
 
-        $this->assertEquals(0, $result->errorCount());
-        $this->assertEquals(1, $result->failureCount());
+        $this->assertSame(0, $result->errorCount());
+        $this->assertSame(1, $result->failureCount());
         $this->assertCount(1, $result);
-        $this->assertEquals(1, $test->getNumAssertions());
+        $this->assertSame(1, $test->getNumAssertions());
     }
 
-    public function testMockPredictionFailure()
+    public function testMockPredictionFailure(): void
     {
         $test = new MockFailure('testMethod');
+
         $result = $test->run();
 
-        $this->assertEquals(0, $result->errorCount());
-        $this->assertEquals(1, $result->failureCount());
+        $this->assertSame(0, $result->errorCount());
+        $this->assertSame(1, $result->failureCount());
         $this->assertCount(1, $result);
-        $this->assertEquals(1, $test->getNumAssertions());
+        $this->assertSame(1, $test->getNumAssertions());
     }
 
-    public function testDoublingError()
+    public function testDoublingError(): void
     {
         $test = new Error('testMethod');
+
         $result = $test->run();
 
-        $this->assertEquals(1, $result->errorCount());
-        $this->assertEquals(0, $result->failureCount());
+        $this->assertSame(1, $result->errorCount());
+        $this->assertSame(0, $result->failureCount());
         $this->assertCount(1, $result);
-        $this->assertEquals(0, $test->getNumAssertions());
+        $this->assertSame(0, $test->getNumAssertions());
     }
 }
diff --git a/composer.json b/composer.json
index 6937d75..6490597 100644
--- a/composer.json
+++ b/composer.json
@@ -11,12 +11,12 @@
             "email": "stof@notk.org"
         }
     ],
+    "minimum-stability": "dev",
+    "prefer-stable": true,
     "require": {
-        "php": ">=5.3.3",
-        "phpspec/prophecy": "~1.3"
-    },
-    "suggest": {
-        "phpunit/phpunit": "if it is not installed globally"
+        "php": "^7.3",
+        "phpspec/prophecy": "^1.3",
+        "phpunit/phpunit":"^9.1"
     },
     "autoload": {
         "psr-4": {
@@ -25,7 +25,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "1.0.x-dev"
+            "dev-master": "2.0-dev"
         }
     }
 }