add filter validation

Author: samsonasik

src/Assert/Filter.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ArrayLookup\Assert;
+
+use InvalidArgumentException;
+use ReflectionFunction;
+use ReflectionMethod;
+use ReflectionNamedType;
+use TypeError;
+
+use function sprintf;
+
+final class Filter
+{
+    public static function boolean(callable $filter): void
+    {
+        try {
+            $reflection = new ReflectionFunction($filter);
+        } catch (TypeError) {
+            $reflection = new ReflectionMethod($filter, '__invoke');
+        }
+
+        $returnType = $reflection->getReturnType();
+
+        if (! $returnType instanceof ReflectionNamedType) {
+            throw new InvalidArgumentException('Expected a bool return type on callable filter, null given');
+        }
+
+        $returnTypeName = $returnType->getName();
+        if ($returnTypeName !== 'bool') {
+            throw new InvalidArgumentException(sprintf(
+                'Expected a bool return type on callable filter, %s given',
+                $returnTypeName
+            ));
+        }
+    }
+}

tests/FilterTest.php

@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ArrayLookup\Tests;
+
+use ArrayLookup\AtLeast;
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
+
+final class FilterTest extends TestCase
+{
+    public function testOnceWithFilterInvokableClass(): void
+    {
+        $data   = [1, 2, 3];
+        $filter = new class {
+            public function __invoke(int $datum): bool
+            {
+                return $datum === 1;
+            }
+        };
+
+        $this->assertTrue(AtLeast::once($data, $filter));
+    }
+
+    public function testWithoutReturnTypeCallable(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Expected a bool return type on callable filter, null given');
+
+        $data = [1, 2, 3];
+
+        // phpcs:disable
+        $filter = new class {
+            public function __invoke(int $datum)
+            {
+                return $datum === 1;
+            }
+        };
+        // phpcs:enable
+
+        $this->assertTrue(AtLeast::once($data, $filter));
+    }
+
+    public function testWithNonBoolReturnTypeCallable(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Expected a bool return type on callable filter, string given');
+
+        $data   = [1, 2, 3];
+        $filter = new class {
+            public function __invoke(int $datum): string
+            {
+                return 'test';
+            }
+        };
+
+        $this->assertTrue(AtLeast::once($data, $filter));
+    }
+}