feat(json-format): lowercase span name and service name as per swagger definition (#175)

https://zipkin.io/zipkin-api/\#/default/post_spans.

Author: jcchavezs

src/Zipkin/Reporters/JsonV2Serializer.php

@@ -31,9 +31,9 @@ public function serialize(array $spans): string
         return '[' . implode(',', $spansAsArray) . ']';
     }
 
-    private function serializeEndpoint(Endpoint $endpoint): string
+    private static function serializeEndpoint(Endpoint $endpoint): string
     {
-        $endpointStr =  '{"serviceName":"' . $endpoint->getServiceName() . '"';
+        $endpointStr =  '{"serviceName":"' . \strtolower($endpoint->getServiceName()) . '"';
 
         if ($endpoint->getIpv4() !== null) {
             $endpointStr .= ',"ipv4":"' . $endpoint->getIpv4() . '"';
@@ -54,10 +54,13 @@ private function serializeSpan(ReadbackSpan $span): string
     {
         $spanStr =
             '{"id":"' . $span->getSpanId() . '"'
-            . ',"name":"' . $span->getName() . '"'
             . ',"traceId":"' . $span->getTraceId() . '"'
             . ',"timestamp":' . $span->getTimestamp();
 
+        if ($span->getName() !== null) {
+            $spanStr .= ',"name":"' . \strtolower($span->getName()) . '"';
+        }
+
         if ($span->getDuration() !== null) {
             $spanStr .= ',"duration":' . $span->getDuration();
         }

tests/Unit/Reporters/HttpTest.php

@@ -15,8 +15,8 @@
 
 final class HttpTest extends TestCase
 {
-    const PAYLOAD = '[{"id":"%s","name":"test","traceId":"%s",'
-        . '"timestamp":%d,"localEndpoint":{"serviceName":""}}]';
+    const PAYLOAD = '[{"id":"%s","traceId":"%s",'
+        . '"timestamp":%d,"name":"test","localEndpoint":{"serviceName":""}}]';
 
     public function testConstructorIsRetrocompatible()
     {

tests/Unit/Propagation/JsonV2SerializerTest.php renamed to tests/Unit/Reporters/JsonV2SerializerTest.php

@@ -1,6 +1,6 @@
 <?php
 
-namespace ZipkinTests\Unit\Propagation;
+namespace ZipkinTests\Unit\Reporters;
 
 use Zipkin\Reporters\JsonV2Serializer;
 use Zipkin\Recording\Span;
@@ -17,9 +17,9 @@ public function testSpanIsSerializedSuccessfully()
         $span = Span::createFromContext($context, $localEndpoint);
         $startTime = 1594044779509687;
         $span->start($startTime);
-        $span->setName('test');
+        $span->setName('Test');
         $span->setKind('CLIENT');
-        $remoteEndpoint = Endpoint::create('service2', null, '2001:0db8:85a3:0000:0000:8a2e:0370:7334', 3302);
+        $remoteEndpoint = Endpoint::create('SERVICE2', null, '2001:0db8:85a3:0000:0000:8a2e:0370:7334', 3302);
         $span->setRemoteEndpoint($remoteEndpoint);
         $span->tag('test_key', 'test_value');
         $span->annotate($startTime + 100, 'test_annotarion');
@@ -29,7 +29,7 @@ public function testSpanIsSerializedSuccessfully()
         $serializedSpans = $serializer->serialize([$span]);
 
         $expectedSerialization = '[{'
-            . '"id":"186f11b67460db4d","name":"test","traceId":"186f11b67460db4d","timestamp":1594044779509687,'
+            . '"id":"186f11b67460db4d","traceId":"186f11b67460db4d","timestamp":1594044779509687,"name":"test",'
             . '"duration":1000,"localEndpoint":{"serviceName":"service1","ipv4":"192.168.0.11","port":3301},'
             . '"kind":"CLIENT",'
             . '"remoteEndpoint":{"serviceName":"service2","ipv6":"2001:0db8:85a3:0000:0000:8a2e:0370:7334","port":3302}'
@@ -55,7 +55,7 @@ public function testErrorTagIsNotClobberedBySpanError()
         $serializedSpans = $serializer->serialize([$span]);
 
         $expectedSerialization = '[{'
-            . '"id":"186f11b67460db4d","name":"test","traceId":"186f11b67460db4d","timestamp":1594044779509688,'
+            . '"id":"186f11b67460db4d","traceId":"186f11b67460db4d","timestamp":1594044779509688,"name":"test",'
             . '"duration":1000,"localEndpoint":{"serviceName":"service1","ipv4":"192.168.0.11","port":3301},'
             . '"tags":{"test_key":"test_value","error":"priority_error"}'
             . '}]';