diff --git a/.circleci/config.yml b/.circleci/config.yml
index 8cf3de8..02f4369 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,29 +1,24 @@
-version: 2.0
+version: 2.1
 jobs:
   build:
-    machine:
-      image: ubuntu-2004:202010-01
+    docker:
+      - image: circleci/php:7.3
     environment:
       CC_TEST_REPORTER_ID: 7b1ac919c90c8ea384b4998b267e0f629185a26ffdf0f96ef4f4a09f53488ed2
+      XDEBUG_MODE: coverage
     working_directory: ~/repo
     steps:
       - checkout
       - run:
-          name: Setup DDEV
-          command: |
-            curl -LO https://raw.githubusercontent.com/drud/ddev/master/scripts/install_ddev.sh && bash install_ddev.sh
-      - run:
-          name: Setup Code Climate test-reporter
+          name: Set up Code Climate test-reporter
           command: |
             curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 > ./cc-test-reporter
             chmod +x ./cc-test-reporter
       - run:
           name: Run tests
           command: |
-            ddev start
-            ddev xdebug
-            ddev composer install
+            composer install
             ./cc-test-reporter before-build
-            ddev exec ./vendor/bin/phpunit --testsuite all --coverage-clover clover.xml
+            ./vendor/bin/phpunit --testsuite all --coverage-clover clover.xml
             sed -i 's+/var/www/html/+/home/circleci/repo/+g' clover.xml
             ./cc-test-reporter after-build --coverage-input-type clover --exit-code $?
diff --git a/.gitignore b/.gitignore
index f42423d..983cd7b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@
 vendor
 composer.lock
 coverage
+.vscode
+.phpunit*
\ No newline at end of file
diff --git a/README.md b/README.md
index 3559da6..9075bb3 100644
--- a/README.md
+++ b/README.md
@@ -20,21 +20,21 @@ Creating a double for the body object with plain phpunit might look like this:
 ```php
 $organ = $this->getMockBuilder(Organ::class)
     ->disableOriginalConstructor()
-    ->setMethods(['getName'])
+    ->onlyMethods(['getName'])
     ->getMock();
 
 $organ->method('getName')->willReturn('brain');
 
 $system = $this->getMockBuilder(System::class)
   ->disableOriginalConstructor()
-  ->setMethods(['getOrgan'])
+  ->onlyMethods(['getOrgan'])
   ->getMock();
 
 $system->method('getOrgan')->willReturn($organ);
 
 $body = $this->getMockBuilder(Body::class)
   ->disableOriginalConstructor()
-  ->setMethods(['getSystem'])
+  ->onlyMethods(['getSystem'])
   ->getMock();
 
 $body->method('getSystem')->willReturn($system);
diff --git a/phpunit.xml b/phpunit.xml
index b4d7c1e..444f5b1 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,18 +1,13 @@
-<phpunit
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/6.3/phpunit.xsd"
-    verbose="false">
-
-    <testsuites>
-        <testsuite name="all">
-            <directory suffix="Test.php" phpVersion="7.2" phpVersionOperator=">=">test</directory>
-        </testsuite>
-    </testsuites>
-
-    <filter>
-        <whitelist processUncoveredFilesFromWhitelist="true">
-            <directory suffix=".php">src</directory>
-        </whitelist>
-    </filter>
-
+<?xml version="1.0"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd" verbose="false">
+  <coverage processUncoveredFiles="true">
+    <include>
+      <directory suffix=".php">src</directory>
+    </include>
+  </coverage>
+  <testsuites>
+    <testsuite name="all">
+      <directory suffix="Test.php" phpVersion="7.2" phpVersionOperator="&gt;=">test</directory>
+    </testsuite>
+  </testsuites>
 </phpunit>
diff --git a/src/Chain.php b/src/Chain.php
index dc542d3..31a9b94 100644
--- a/src/Chain.php
+++ b/src/Chain.php
@@ -72,7 +72,7 @@ private function build($objectClass)
         $builder = $this->getBuilder($objectClass);
 
         if (!empty($methods)) {
-            $builder->setMethods($methods);
+            $builder->onlyMethods($methods);
         }
         $mock = $builder->getMockForAbstractClass();
 
diff --git a/test/ChainTest.php b/test/ChainTest.php
index 7f7757e..e12a8ee 100644
--- a/test/ChainTest.php
+++ b/test/ChainTest.php
@@ -12,7 +12,8 @@
 
 class ChainTest extends TestCase
 {
-    public function test() {
+    public function test()
+    {
         $organNames = (new Sequence())->add('mouth')->add('stomach');
 
         $organ = (new Chain($this))
@@ -33,7 +34,8 @@ public function test() {
         $this->assertEquals($body->getSystem('digestive')->getOrgan('mouth')->getName(), 'mouth');
     }
 
-    public function test2() {
+    public function test2()
+    {
         $organNames = (new Sequence())->add('mouth')->add('stomach');
 
         $organ = (new Chain($this))
@@ -56,7 +58,8 @@ public function test2() {
     }
 
 
-    public function test3() {
+    public function test3()
+    {
         $organs = (new Options())
           ->add('mouth', Organ::class)
           ->add('stomach', Organ::class);
@@ -81,7 +84,8 @@ public function test3() {
         $this->assertEquals(json_encode(['stomach']), json_encode($chain->getStoredInput('organ')));
     }
 
-    public function test4() {
+    public function test4()
+    {
         $this->expectExceptionMessage("blah");
 
         $system = (new Chain($this))
@@ -94,19 +98,22 @@ public function test4() {
         $body->getSystem("blah");
     }
 
-    public function testNonExistentMethod() {
-      $this->expectExceptionMessage("method blah does not exist in MockChainTest\Anatomy\Organ");
-      (new Chain($this))
+    public function testNonExistentMethod()
+    {
+        $this->expectExceptionMessage('Trying to set mock method "blah" with onlyMethods');
+        (new Chain($this))
         ->add(Organ::class, 'blah', null)
         ->getMock();
     }
 
-    public function testUsingAdddIncorrectly() {
-      $this->expectExceptionMessage("You should use the add method before using addd.");
-      (new Chain($this))->addd("hello");
+    public function testUsingAdddIncorrectly()
+    {
+        $this->expectExceptionMessage("You should use the add method before using addd.");
+        (new Chain($this))->addd("hello");
     }
 
-    public function testNonExistentOption() {
+    public function testNonExistentOption()
+    {
         $this->expectExceptionMessage('Option digestive does not exist');
         $options = new Options();
         $mock = (new Chain($this))
@@ -114,4 +121,4 @@ public function testNonExistentOption() {
             ->getMock();
         $mock->getSystem("digestive");
     }
-}
\ No newline at end of file
+}
diff --git a/test/OptionsTest.php b/test/OptionsTest.php
index c55a956..8f52ed9 100644
--- a/test/OptionsTest.php
+++ b/test/OptionsTest.php
@@ -8,18 +8,21 @@
 
 class OptionsTest extends TestCase
 {
-  public function test() {
-      $options = new Options();
-      $options->add("hello", "goodbye");
-      $options->add("hola", "chao");
-      $options->add("multi", (new Sequence())->add('adieu')->add('shalom'));
+    public function test()
+    {
+        $options = new Options();
+        $options->add("hello", "goodbye");
+        $options->add("hola", "chao");
+        $options->add("multi", (new Sequence())->add('adieu')->add('shalom'));
 
-      $this->assertEquals(json_encode($options->options()), json_encode(["hello", "hola", "multi"]));
-      $this->assertEquals($options->return("hello"), "goodbye");
-      $this->assertEquals($options->return("hola"), "chao");
-      $this->assertEquals($options->return("multi"), "adieu");
-      $this->assertEquals($options->return("multi"), "shalom");
-      $this->assertEquals($options->return("multi"), "shalom");
-      $this->assertNull($options->return('not-an-option'));
-  }
-}
\ No newline at end of file
+        $this->assertEquals(json_encode($options->options()), json_encode(["hello", "hola", "multi"]));
+        $this->assertEquals($options->return("hello"), "goodbye");
+        $this->assertEquals($options->return("hola"), "chao");
+        $this->assertEquals($options->return("multi"), "adieu");
+        $this->assertEquals($options->return("multi"), "shalom");
+        $this->assertEquals($options->return("multi"), "shalom");
+        $this->assertNull($options->return('not-an-option'));
+        $options->index(2);
+        $this->assertEquals(2, $options->getIndex());
+    }
+}
diff --git a/test/SequenceTest.php b/test/SequenceTest.php
index 54ec6b6..f8a2a6c 100644
--- a/test/SequenceTest.php
+++ b/test/SequenceTest.php
@@ -10,7 +10,8 @@
 
 class SequenceTest extends TestCase
 {
-    public function test() {
+    public function test()
+    {
         $sequence = new Sequence();
         $sequence->add(null);
         $sequence->add(1);
@@ -22,16 +23,17 @@ public function test() {
         $this->assertEquals($sequence->return(), 2);
     }
 
-    public function testSequenceThroughChain() {
-      $sequence = (new Sequence())
+    public function testSequenceThroughChain()
+    {
+        $sequence = (new Sequence())
         ->add(null)
         ->add("hello");
 
-      $mock = (new Chain($this))
+        $mock = (new Chain($this))
         ->add(Organ::class, 'getName', $sequence)
         ->getMock();
 
-      $this->assertNull($mock->getName());
-      $this->assertEquals("hello", $mock->getName());
+        $this->assertNull($mock->getName());
+        $this->assertEquals("hello", $mock->getName());
     }
-}
\ No newline at end of file
+}