test: add unit tests for NdJson stream reading functionality

Author: awu

tests/Stream/NdJsonTest.php

@@ -0,0 +1,143 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Thenativeweb\Eventsourcingdb\Tests\Stream;
+
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\StreamInterface;
+use RuntimeException;
+use Thenativeweb\Eventsourcingdb\Stream\NdJson;
+use Thenativeweb\Eventsourcingdb\Stream\ReadEventLine;
+
+final class NdJsonTest extends TestCase
+{
+    public function getEofReturnValues(string $jsonLines): array
+    {
+        $byteLine = $this->getReadReturnValues($jsonLines);
+
+        $eofReturnValues = array_fill(0, count($byteLine), false);
+        $eofReturnValues[] = true;
+
+        return $eofReturnValues;
+    }
+
+    public function getReadReturnValues(string $jsonLines): array
+    {
+        $eofFixChar = '-';
+        $jsonLineCount = substr_count($jsonLines, "\n");
+        return str_split($jsonLines . str_repeat($eofFixChar, $jsonLineCount));
+    }
+
+    public function testReadLineReadsUntilNewline(): void
+    {
+        $stream = $this->createMock(StreamInterface::class);
+        $stream->method('eof')
+            ->willReturnOnConsecutiveCalls(false, false, false, true);
+
+        $stream->method('read')
+            ->willReturnOnConsecutiveCalls('f', 'o', "\n");
+
+        $line = NdJson::readLine($stream);
+        $this->assertSame("fo\n", $line);
+    }
+
+    public function testReadLineReturnsEmptyStringIfNothingToRead(): void
+    {
+        $stream = $this->createMock(StreamInterface::class);
+        $stream->method('eof')->willReturn(false);
+        $stream->method('read')->willReturn('');
+
+        $line = NdJson::readLine($stream);
+        $this->assertSame('', $line);
+    }
+
+    public function testReadStreamYieldsEventLines(): void
+    {
+        $json1 = json_encode([
+            'type' => 'event1',
+            'payload' => [
+                'foo' => 'bar',
+            ],
+        ]) . "\n";
+        $json2 = json_encode([
+            'type' => 'event2',
+            'payload' => [
+                'baz' => 'qux',
+            ],
+        ]) . "\n";
+        $jsonLines = $json1 . $json2;
+
+        $stream = $this->createMock(StreamInterface::class);
+        $stream->method('eof')
+            ->willReturnOnConsecutiveCalls(...$this->getEofReturnValues($jsonLines));
+        $stream->method('read')
+            ->willReturnOnConsecutiveCalls(...$this->getReadReturnValues($jsonLines));
+
+        $events = iterator_to_array(NdJson::readStream($stream));
+
+        $this->assertCount(2, $events);
+        $this->assertInstanceOf(ReadEventLine::class, $events[0]);
+        $this->assertSame('event1', $events[0]->type);
+        $this->assertSame([
+            'foo' => 'bar',
+        ], $events[0]->payload);
+
+        $this->assertInstanceOf(ReadEventLine::class, $events[1]);
+        $this->assertSame('event2', $events[1]->type);
+        $this->assertSame([
+            'baz' => 'qux',
+        ], $events[1]->payload);
+    }
+
+    public function testReadStreamSkipsEmptyLines(): void
+    {
+        $jsonLines = json_encode([
+            'type' => 'event',
+            'payload' => [],
+        ]) . "\n";
+
+        $stream = $this->createMock(StreamInterface::class);
+        $stream->method('eof')
+            ->willReturnOnConsecutiveCalls(...$this->getEofReturnValues($jsonLines));
+        $stream->method('read')
+            ->willReturnOnConsecutiveCalls(...$this->getReadReturnValues($jsonLines));
+
+        $events = iterator_to_array(NdJson::readStream($stream));
+
+        $this->assertCount(1, $events);
+        $this->assertSame('event', $events[0]->type);
+    }
+
+    public function testReadStreamThrowsOnInvalidJson(): void
+    {
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage('Failed to read events.');
+
+        $jsonLines = "{ invalid json }\n";
+
+        $stream = $this->createMock(StreamInterface::class);
+        $stream->method('eof')
+            ->willReturnOnConsecutiveCalls(...$this->getEofReturnValues($jsonLines));
+        $stream->method('read')
+            ->willReturnOnConsecutiveCalls(...$this->getReadReturnValues($jsonLines));
+
+        iterator_to_array(NdJson::readStream($stream));
+    }
+
+    public function testReadStreamThrowsIfDecodedJsonIsNotArray(): void
+    {
+        $this->expectException(RuntimeException::class);
+        $this->expectExceptionMessage('Failed to read events, expected an array.');
+
+        $jsonLines = json_encode('just a string') . "\n";
+
+        $stream = $this->createMock(StreamInterface::class);
+        $stream->method('eof')
+            ->willReturnOnConsecutiveCalls(...$this->getEofReturnValues($jsonLines));
+        $stream->method('read')
+            ->willReturnOnConsecutiveCalls(...$this->getReadReturnValues($jsonLines));
+
+        iterator_to_array(NdJson::readStream($stream));
+    }
+}