From 5cc908478babb01523ca078bef8054e247f4b566 Mon Sep 17 00:00:00 2001
From: widmogrod <widmogrod@gmail.com>
Date: Wed, 20 Dec 2017 18:20:48 +0100
Subject: [PATCH] Functiona\filter test

---
 src/Functional/listt.php       | 23 ----------------------
 test/Functional/FilterTest.php | 44 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 23 deletions(-)
 create mode 100644 test/Functional/FilterTest.php

diff --git a/src/Functional/listt.php b/src/Functional/listt.php
index 89bfb94..f757a38 100644
--- a/src/Functional/listt.php
+++ b/src/Functional/listt.php
@@ -52,29 +52,6 @@ function concat(Foldable $xs)
     }, Listt::mempty(), $xs);
 }
 
-///**
-// * map f xs is the list obtained by applying f to each element of xs, i.e.,
-// *
-// * map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn]
-// * map f [x1, x2, ...] == [f x1, f x2, ...]
-// */
-//function map()
-//{
-//    // TODO
-//}
-//
-///**
-// * filter :: (a -> Bool) -> [a] -> [a] Source #
-// *
-// * filter, applied to a predicate and a list, returns the list of those elements that satisfy the predicate; i.e.,
-// *
-// * filter p xs = [ x | x <- xs, p x]
-// */
-//function filter()
-//{
-//    // TODO
-//}
-
 const prepend = 'Widmogrod\Functional\prepend';
 
 /**
diff --git a/test/Functional/FilterTest.php b/test/Functional/FilterTest.php
new file mode 100644
index 0000000..7242c57
--- /dev/null
+++ b/test/Functional/FilterTest.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace test\Functional;
+
+use function Widmogrod\Functional\filter;
+use function Widmogrod\Functional\fromIterable;
+
+class FilterTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function test_it_should_filter_with_maybe(
+        $list,
+        $expected
+    ) {
+        $filter = function (int $i): bool {
+            return $i % 2 === 1;
+        };
+
+        $this->assertEquals(
+            $expected,
+            filter($filter, $list)
+        );
+    }
+
+    public function provideData()
+    {
+        return [
+            'simple list' => [
+                '$list' => fromIterable([1, 2, 3, 4, 5]),
+                '$expected' => fromIterable([1, 3, 5])
+            ],
+            'empty list' => [
+                '$list' => fromIterable([]),
+                '$expected' => fromIterable([])
+            ],
+            'traversable' => [
+                '$list' => fromIterable(new \ArrayIterator([1, 2, 3, 4, 5])),
+                '$expected' => fromIterable([1, 3, 5]),
+            ],
+        ];
+    }
+}
-- 
2.11.0