Merge pull request #2 from snowio/feature/segment-filteration

Add segment filtration

src/SegmentSet.php

@@ -85,6 +85,19 @@ public function getIterator()
         }
     }
 
+    public function filter(callable $predicate): SegmentSet
+    {
+        return self::of(array_filter($this->segments, $predicate));
+    }
+
+    public function first(): ?Segment
+    {
+        if ($this->size() === 0) {
+            return null;
+        }
+        return reset($this->segments);
+    }
+
     public function toJson(?string $action): array
     {
         $itemData = [];

tests/unit/SegmentSetTest.php

@@ -3,6 +3,7 @@
 namespace SnowIO\DataLakeDataModel\Test;
 
 use PHPUnit\Framework\TestCase;
+use SnowIO\DataLakeDataModel\Segment;
 use SnowIO\DataLakeDataModel\SegmentSet;
 use SnowIO\DataLakeDataModel\Test\ACME\DataLake\Segments\Price;
 use SnowIO\DataLakeDataModel\Test\ACME\DataLake\Segments\Stock;
@@ -68,4 +69,36 @@ public function testEquals()
         self::assertFalse($otherSegments->equals($segments));
     }
 
+    public function testFiltration()
+    {
+        $segments = SegmentSet::of([
+            Price::fromJson(SegmentTest::getPriceJson()),
+            Stock::fromJson(SegmentTest::getStockJson())
+        ]);
+
+        $filteredSegments = $segments->filter(function (Segment $segment) {
+           return $segment->getSegmentId()  === Price::NAME;
+        });
+
+        self::assertEquals(1, $filteredSegments->size());
+    }
+
+    public function testFirst()
+    {
+        $segments = SegmentSet::of([
+            $price = Price::fromJson(SegmentTest::getPriceJson()),
+            Stock::fromJson(SegmentTest::getStockJson())
+        ]);
+
+        $actual = $segments->first();
+        self::assertTrue($actual->equals($price));
+    }
+
+    public function testFirstWithEmptySegmentSet()
+    {
+        $segments = SegmentSet::of([]);
+
+        $actual = $segments->first();
+        self::assertNull($actual);
+    }
 }