Add basic container implementation

tests/.snapshots/success.txt

@@ -118,6 +118,15 @@
    PASS  Tests\Unit\Support\Backtrace
   ✓ it gets file name from called file
 
+   PASS  Tests\Unit\Support\Container
+  ✓ it exists
+  ✓ it gets an instance
+  ✓ it creates an instance and resolves parameters
+  ✓ it creates an instance and resolves also sub parameters
+  ✓ it can resolve builtin value types
+  ✓ it cannot resolve a parameter that requires additional dependencies
+  ✓ it cannot resolve a parameter without type
+
    PASS  Tests\Unit\Support\Reflection
   ✓ it gets file name from closure
   ✓ it gets property values
@@ -134,5 +143,10 @@
    WARN  Tests\Visual\Success
   s visual snapshot of test suite on success
 
+<<<<<<< HEAD
   Tests:  6 skipped, 71 passed
   Time:   2.89s
+=======
+  Tests:  6 skipped, 76 passed
+  Time:   3.32s
+>>>>>>> 84c9078... Add basic container implementation

tests/Unit/Support/Container.php

@@ -0,0 +1,71 @@
+<?php
+
+use Pest\Exceptions\ShouldNotHappen;
+use Pest\Support\Container;
+use Pest\TestSuite;
+
+uses()->group('container');
+
+beforeEach(function () {
+    $this->container = new Container();
+});
+
+it('exists')
+    ->assertTrue(class_exists(Container::class));
+
+it('gets an instance', function () {
+    $this->container->add(Container::class, $this->container);
+    assertSame($this->container, $this->container->get(Container::class));
+});
+
+it('creates an instance and resolves parameters', function () {
+    $this->container->add(Container::class, $this->container);
+    $instance = $this->container->get(ClassWithDependency::class);
+
+    assertInstanceOf(ClassWithDependency::class, $instance);
+});
+
+it('creates an instance and resolves also sub parameters', function () {
+    $this->container->add(Container::class, $this->container);
+    $instance = $this->container->get(ClassWithSubDependency::class);
+
+    assertInstanceOf(ClassWithSubDependency::class, $instance);
+});
+
+it('can resolve builtin value types', function () {
+    $this->container->add('rootPath', getcwd());
+
+    $instance = $this->container->get(TestSuite::class);
+    assertInstanceOf(TestSuite::class, $instance);
+});
+
+it('cannot resolve a parameter that requires additional dependencies', function () {
+    $this->expectException(ShouldNotHappen::class);
+    $this->container->get(ClassWithDependency::class);
+});
+
+it('cannot resolve a parameter without type', function () {
+    $this->expectException(ShouldNotHappen::class);
+    $this->container->get(ClassWithoutTypeParameter::class);
+});
+
+class ClassWithDependency
+{
+    public function __construct(Container $container)
+    {
+    }
+}
+
+class ClassWithSubDependency
+{
+    public function __construct(ClassWithDependency $param)
+    {
+    }
+}
+
+class ClassWithoutTypeParameter
+{
+    public function __construct($param)
+    {
+    }
+}