test: initial tests

Author: Greg Bowler

.gitignore

@@ -0,0 +1,3 @@
+/.idea/
+/vendor/
+.phpunit.result.cache

src/Cache.php

@@ -0,0 +1,23 @@
+<?php
+namespace Gt\FileCache;
+
+class Cache {
+	public function __construct(
+		private string $path = "cache"
+	) {
+		if(!is_dir($path)) {
+			mkdir($path, 0775, true);
+		}
+	}
+
+	public function get(string $name, callable $callback):mixed {
+		$fileName = $this->path . "/$name";
+		if(file_exists($fileName)) {
+			return unserialize(file_get_contents($fileName));
+		}
+
+		$value = $callback();
+		file_put_contents($fileName, serialize($value));
+		return $value;
+	}
+}

test/phpunit/CacheTest.php

@@ -1,10 +1,42 @@
 <?php
 namespace Gt\FileCache\Test;
 
+use Gt\FileCache\Cache;
 use PHPUnit\Framework\TestCase;
 
 class CacheTest extends TestCase {
-	public function test():void {
-		self::assertTrue(true);
+	public function testGet_expectedValueReturned():void {
+		$sut = new Cache(sys_get_temp_dir() . "/phpgt-filecache");
+		$value = "test-value";
+		$result = $sut->get("test", fn() => $value);
+		self::assertSame($value, $result);
+	}
+
+	public function testGet_expectedValueReturnedOnMultipleCalls():void {
+		$sut = new Cache(sys_get_temp_dir() . "/phpgt-filecache");
+		$value = "test-value";
+		$result = $sut->get("test", fn() => $value);
+		self::assertSame($value, $result);
+		$result = $sut->get("test", fn() => $value);
+		self::assertSame($value, $result);
+	}
+
+	public function testGet_multipleCallsDoesNotCallbackMultipleTimes():void {
+		$sut = new Cache(sys_get_temp_dir() . "/phpgt/filecache");
+		$name = uniqid("test-");
+		$value = "test-value-123";
+		$count = 0;
+
+		$callback = function()use($value, &$count):string {
+			$count++;
+			return $value;
+		};
+		$result = $sut->get($name, $callback);
+		self::assertSame($value, $result);
+		self::assertSame(1, $count);
+
+		$result = $sut->get($name, $callback);
+		self::assertSame($value, $result);
+		self::assertSame(1, $count);
 	}
 }