Task 1: Calculator init

tasks/task_01/tests/CalculatorTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests;
+
+use PHPUnit\Framework\TestCase;
+use App\Calculator;
+use App\Operation;
+use InvalidArgumentException;
+
+class CalculatorTest extends TestCase
+{
+    private Calculator $calculator;
+
+    protected function setUp(): void
+    {
+        $this->calculator = new Calculator();
+    }
+
+    public function testAdd(): void
+    {
+        $result = $this->calculator->calculate(10, 5, Operation::ADD);
+        $this->assertEquals(15, $result);
+    }
+
+    public function testSubtract(): void
+    {
+        $result = $this->calculator->calculate(10, 5, Operation::SUBTRACT);
+        $this->assertEquals(5, $result);
+    }
+
+    public function testMultiply(): void
+    {
+        $result = $this->calculator->calculate(10, 5, Operation::MULTIPLY);
+        $this->assertEquals(50, $result);
+    }
+
+    public function testDivide(): void
+    {
+        $result = $this->calculator->calculate(10, 5, Operation::DIVIDE);
+        $this->assertEquals(2, $result);
+    }
+
+    public function testDivideByZero(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->calculator->calculate(10, 0, Operation::DIVIDE);
+    }
+}