Add test for EventSource implementation

src/main/php/web/io/EventSource.class.php

@@ -3,7 +3,13 @@
 use IteratorAggregate, Traversable;
 use io\streams\{InputStream, StringReader};
 
-/** @see https://developer.mozilla.org/en-US/docs/Web/API/EventSource */
+/**
+ * Event source is the receiving end for server-sent events, handling the
+ * `text/event-stream` wire format.
+ *
+ * @test  web.unittest.io.EventSourceTest
+ * @see   https://developer.mozilla.org/en-US/docs/Web/API/EventSource
+ */
 class EventSource implements IteratorAggregate {
   private $reader;
 
@@ -15,7 +21,7 @@ public function __construct(InputStream $in) {
   /** Yields events and associated data */
   public function getIterator(): Traversable {
     $event= null;
-    while ($line= $this->reader->readLine()) {
+    while (null !== ($line= $this->reader->readLine())) {
       if (0 === strncmp($line, 'event: ', 7)) {
         $event= substr($line, 7);
       } else if (0 === strncmp($line, 'data: ', 6)) {

src/test/php/web/unittest/io/EventSourceTest.class.php

@@ -0,0 +1,39 @@
+<?php namespace web\unittest\io;
+
+use io\streams\{InputStream, MemoryInputStream};
+use test\{Assert, Test, Values};
+use web\io\EventSource;
+
+class EventSourceTest {
+
+  /** Returns an input stream from the given lines */
+  private function stream(array $lines): InputStream {
+    return new MemoryInputStream(implode("\n", $lines));
+  }
+
+  /** @return iterable */
+  private function inputs() {
+    yield [[], []];
+    yield [[''], []];
+    yield [['data: One'], [[null => 'One']]];
+    yield [['', 'data: One'], [[null => 'One']]];
+    yield [['data: One', '', 'data: Two'], [[null => 'One'], [null => 'Two']]];
+    yield [['event: test', 'data: One'], [['test' => 'One']]];
+    yield [['event: test', 'data: One', '', 'data: Two'], [['test' => 'One'], [null => 'Two']]];
+  }
+
+  #[Test]
+  public function can_create() {
+    new EventSource($this->stream([]));
+  }
+
+  #[Test, Values(from: 'inputs')]
+  public function events($lines, $expected) {
+    $events= new EventSource($this->stream($lines));
+    $actual= [];
+    foreach ($events as $type => $event) {
+      $actual[]= [$type => $event];
+    }
+    Assert::equals($expected, $actual);
+  }
+}