adding one more unit test

Author: Ashish Aggarwal

core/src/main/java/com/expedia/www/haystack/client/dispatchers/clients/HttpCollectorClient.java

@@ -81,8 +81,9 @@ public boolean send(Span span) throws ClientException {
         if (headers != null && headers.length > 0) {
             post.setHeaders(headers);
         }
-        post.setHeader(new BasicHeader("Content-Type", "application/octet-stream"));
-        post.setEntity(new ByteArrayEntity(spanBytes));
+        final ByteArrayEntity entity = new ByteArrayEntity(spanBytes);
+        entity.setContentType("application/octet-stream");
+        post.setEntity(entity);
         CloseableHttpResponse response = null;
         try {
             response = httpClient.execute(post);

core/src/test/java/com/expedia/www/haystack/client/dispatchers/clients/HttpCollectorClientTest.java

@@ -102,10 +102,22 @@ public void testFailedDispatch() throws Exception {
         client.send(span);
     }
 
+    @Test(expected = ClientException.class)
+    public void testAnotherFailedDispatch() throws Exception {
+        final Span span = tracer.buildSpan("sad-path").start();
+        span.finish();
+        final ArgumentCaptor<HttpPost> httpPostCapture = ArgumentCaptor.forClass(HttpPost.class);
+        final CloseableHttpClient http = Mockito.mock(CloseableHttpClient.class);
+        when(http.execute(httpPostCapture.capture())).thenThrow(new IOException());
+
+        final HttpCollectorClient client = new HttpCollectorClient("http://myendpoint:8080/span", new HashMap<>(), http);
+        client.send(span);
+    }
+
     private void verifyCapturedHttpPost(final HttpPost httpPost) throws IOException {
         assertEquals(httpPost.getMethod(), "POST");
         assertEquals(httpPost.getURI().toString(), "http://myendpoint:8080/span");
-        assertEquals(httpPost.getFirstHeader("Content-Type").getValue(), "application/octet-stream");
+        assertEquals(httpPost.getEntity().getContentType().getValue(), "application/octet-stream");
         assertEquals(httpPost.getFirstHeader("client-id").getValue(), "my-client");
         com.expedia.open.tracing.Span span = com.expedia.open.tracing.Span.parseFrom(httpPost.getEntity().getContent());
         assertEquals(span.getServiceName(), serviceName);