Add comprehensive test coverage and update notes

tests/Unit/BbcodeFormatterTest.php

@@ -0,0 +1,155 @@
+<?php
+
+namespace s9e\TextFormatter {
+    class Parser
+    {
+        public function parse(string $text): string
+        {
+            return '<r/>';
+        }
+    }
+
+    class Renderer
+    {
+        public function render(string $xml): string
+        {
+            return '<p>ok</p>';
+        }
+    }
+
+    class Configurator
+    {
+        public static bool $returnEmpty = false;
+        public object $plugins;
+        public object $tags;
+
+        public function __construct()
+        {
+            $this->plugins = new class {
+                public function load(string $name): object
+                {
+                    return new class {
+                        public function addFromRepository(string $name): self
+                        {
+                            return $this;
+                        }
+                    };
+                }
+            };
+
+            $this->tags = new class implements \ArrayAccess {
+                public array $store = [];
+                public function add($name)
+                {
+                    $obj = new \stdClass();
+                    $this->store[$name] = $obj;
+                    return $obj;
+                }
+                public function offsetExists($offset): bool
+                {
+                    return array_key_exists($offset, $this->store);
+                }
+                public function offsetGet($offset): mixed
+                {
+                    return $this->store[$offset] ?? null;
+                }
+                public function offsetSet($offset, $value): void
+                {
+                    $this->store[$offset] = $value;
+                }
+                public function offsetUnset($offset): void
+                {
+                    unset($this->store[$offset]);
+                }
+            };
+
+            $this->tags['QUOTE'] = new \stdClass();
+        }
+
+        public function finalize(): array
+        {
+            if (self::$returnEmpty) {
+                return [];
+            }
+
+            return [
+                'parser' => new Parser(),
+                'renderer' => new Renderer(),
+            ];
+        }
+    }
+}
+
+namespace {
+    use App\Actions\BbcodeFormatter;
+
+    it('returns empty string for null and empty input', function (): void {
+        expect(BbcodeFormatter::format(null))->toBe('');
+        expect(BbcodeFormatter::format(''))->toBe('');
+    });
+
+    it('formats bbcode content', function (): void {
+        $parserProp = new ReflectionProperty(BbcodeFormatter::class, 'parser');
+        $parserProp->setAccessible(true);
+        $parserProp->setValue(
+            \Mockery::mock(\s9e\TextFormatter\Parser::class)
+                ->shouldReceive('parse')
+                ->andReturn('<r/>')
+                ->getMock()
+        );
+
+        $rendererProp = new ReflectionProperty(BbcodeFormatter::class, 'renderer');
+        $rendererProp->setAccessible(true);
+        $rendererProp->setValue(
+            \Mockery::mock(\s9e\TextFormatter\Renderer::class)
+                ->shouldReceive('render')
+                ->andReturn('<b>Bold</b>')
+                ->getMock()
+        );
+
+        $html = BbcodeFormatter::format('[b]Bold[/b]');
+
+        expect($html)->toContain('<b>');
+    });
+
+    it('initializes parser and renderer when not set', function (): void {
+        $parserProp = new ReflectionProperty(BbcodeFormatter::class, 'parser');
+        $parserProp->setAccessible(true);
+        $parserProp->setValue(null);
+
+        $rendererProp = new ReflectionProperty(BbcodeFormatter::class, 'renderer');
+        $rendererProp->setAccessible(true);
+        $rendererProp->setValue(null);
+
+        $html = BbcodeFormatter::format('[b]Bold[/b]');
+
+        expect($html)->toBeString();
+        expect($parserProp->getValue())->not->toBeNull();
+        expect($rendererProp->getValue())->not->toBeNull();
+    });
+
+    it('throws when bbcode formatter cannot initialize', function (): void {
+        \s9e\TextFormatter\Configurator::$returnEmpty = true;
+
+        $parserProp = new ReflectionProperty(BbcodeFormatter::class, 'parser');
+        $parserProp->setAccessible(true);
+        $parserProp->setValue(null);
+
+        $rendererProp = new ReflectionProperty(BbcodeFormatter::class, 'renderer');
+        $rendererProp->setAccessible(true);
+        $rendererProp->setValue(null);
+
+        try {
+            BbcodeFormatter::format('test');
+            $this->fail('Expected exception not thrown.');
+        } catch (Throwable $e) {
+            expect($e)->toBeInstanceOf(RuntimeException::class);
+        } finally {
+            \s9e\TextFormatter\Configurator::$returnEmpty = false;
+        }
+    });
+
+    afterEach(function (): void {
+        \Mockery::close();
+    });
+}