diff --git a/composer.json b/composer.json
index 3024ee7..6c2dd75 100644
--- a/composer.json
+++ b/composer.json
@@ -29,8 +29,13 @@
     "phpunit/phpunit": ">=8.0"
   },
   "autoload": {
-    "psr-0": {
-      "NXP": "src/"
+    "psr-4": {
+      "NXP\\": "src/NXP"
+    }
+  },
+  "autoload-dev": {
+    "psr-4": {
+      "NXP\\Tests\\": "tests/"
     }
   }
 }
diff --git a/tests/MathTest.php b/tests/MathTest.php
index a5061ad..47d89b8 100644
--- a/tests/MathTest.php
+++ b/tests/MathTest.php
@@ -504,7 +504,7 @@ public function testSetVarsAcceptsAllScalars()
         $calculator->setVar('null', null);
         $calculator->setVar('float', 1.1);
         $calculator->setVar('string', 'string');
-        $this->assertEquals(8, count($calculator->getVars()));
+        $this->assertCount(8, $calculator->getVars());
         $this->assertEquals(true, $calculator->getVar('boolTrue'));
         $this->assertEquals(false, $calculator->getVar('boolFalse'));
         $this->assertEquals(1, $calculator->getVar('int'));