Fix CI
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 19e4b60..e0ff8c0 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -48,7 +48,7 @@
       - name: 'Install Dependencies'
         run: |
           sudo luarocks install luaunit
-          sudo luarocks install luasocket
+          sudo luarocks install lua-cjson
       - name: 'Run Tests'
         run: |
           cd lib/skywalking
diff --git a/lib/skywalking/span_test.lua b/lib/skywalking/span_test.lua
index e685142..5ed2ffa 100644
--- a/lib/skywalking/span_test.lua
+++ b/lib/skywalking/span_test.lua
@@ -19,6 +19,7 @@
 local TC = require('tracing_context')
 local Span = require('span')
 local SpanLayer = require("span_layer")
+local cjson = require("cjson")
 
 TestSpan = {}
     function TestSpan:testNewEntry()
@@ -137,10 +138,14 @@
         local spanBuilder = span1:transform()
         lu.assertEquals(#spanBuilder.refs, 1)
         lu.assertNil(spanBuilder.spanLayer)
-        lu.assertEquals(#spanBuilder.spanType, "Entry")
+        lu.assertEquals(spanBuilder.spanType, "Entry")
         lu.assertEquals(#spanBuilder.logs, 1)
         lu.assertEquals(spanBuilder.logs[1].data["logkey"], "logvalue")
         lu.assertEquals(spanBuilder.logs[1].data["logkey1"], "logvalue2")
+
+        local inJSON = cjson.encode(spanBuilder)
+        lu.assertTrue(string.len(inJSON) > 0)
+        -- print(inJSON)
     end
 -- end TestSpan