refactor (#3712)

* test: refactor test suite

* docs

* refactor

* yup

* docs

tests/CacheImplementationTest.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace RssBridge\Tests;
+
+use CacheInterface;
+use PHPUnit\Framework\TestCase;
+
+class CacheImplementationTest extends TestCase
+{
+    public function getCacheClassNames()
+    {
+        $caches = [];
+        foreach (glob(PATH_LIB_CACHES . '*.php') as $path) {
+            $caches[] = [basename($path, '.php')];
+        }
+        return $caches;
+    }
+
+    /**
+     * @dataProvider getCacheClassNames
+     */
+    public function testClassName($path)
+    {
+        $this->assertTrue($path === ucfirst($path), 'class name must start with uppercase character');
+        $this->assertEquals(0, substr_count($path, ' '), 'class name must not contain spaces');
+        $this->assertStringEndsWith('Cache', $path, 'class name must end with "Cache"');
+    }
+
+    /**
+     * @dataProvider getCacheClassNames
+     */
+    public function testClassType($path)
+    {
+        $this->assertTrue(is_subclass_of($path, CacheInterface::class), 'class must be subclass of CacheInterface');
+    }
+}