[mezmoexporter] Test refactoring (open-telemetry#10585)

Some light refactoring in the `mezmoexporter` test suite to facilitate
easier testing in the future.

exporter/mezmoexporter/exporter_test.go

@@ -96,54 +96,88 @@ func createSizedPayloadLogData(payloadSize int) plog.Logs {
  return logs
 }
 
-func TestLogsExporter(t *testing.T) {
- // Spin up a HTTP server to receive the test exporters...
- server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
- assert.Equal(t, "application/json", r.Header.Get("Content-Type"))
- assert.Equal(t, "mezmo-otel-exporter/"+buildInfo.Version, r.Header.Get("User-Agent"))
+type testServer struct {
+ instance *httptest.Server
+ url string
+}
+
+type httpAssertionCallback func(req *http.Request, body MezmoLogBody)
+type testServerParams struct {
+ t *testing.T
+ assertionsCallback httpAssertionCallback
+}
 
+// Creates an HTTP server to test log delivery payloads by applying a set of
+// assertions through the assertCB function.
+func createHTTPServer(params *testServerParams) testServer {
+ httpServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  body, err := ioutil.ReadAll(r.Body)
  if err != nil {
- t.Fatal(err)
+ params.t.Fatal(err)
  }
 
  var logBody MezmoLogBody
  if err = json.Unmarshal(body, &logBody); err != nil {
  w.WriteHeader(http.StatusUnprocessableEntity)
  }
 
+ params.assertionsCallback(r, logBody)
+
  w.WriteHeader(http.StatusOK)
  }))
- defer server.Close()
 
- serverURL, err := url.Parse(server.URL)
- assert.NoError(t, err)
+ serverURL, err := url.Parse(httpServer.URL)
+ assert.NoError(params.t, err)
 
- config := &Config{
- IngestURL: serverURL.String(),
+ server := testServer{
+ instance: httpServer,
+ url: serverURL.String(),
  }
 
- exp := newLogsExporter(config, componenttest.NewNopTelemetrySettings(), buildInfo)
- require.NotNil(t, exp)
+ return server
+}
+
+func createExporter(t *testing.T, config *Config) *mezmoExporter {
+ exporter := newLogsExporter(config, componenttest.NewNopTelemetrySettings(), buildInfo)
+ require.NotNil(t, exporter)
 
- err = exp.start(context.Background(), componenttest.NewNopHost())
+ err := exporter.start(context.Background(), componenttest.NewNopHost())
  require.NoError(t, err)
 
+ return exporter
+}
+
+func TestLogsExporter(t *testing.T) {
+ httpServerParams := testServerParams{
+ t: t,
+ assertionsCallback: func(req *http.Request, body MezmoLogBody) {
+ assert.Equal(t, "application/json", req.Header.Get("Content-Type"))
+ assert.Equal(t, "mezmo-otel-exporter/"+buildInfo.Version, req.Header.Get("User-Agent"))
+ },
+ }
+ server := createHTTPServer(&httpServerParams)
+ defer server.instance.Close()
+
+ config := &Config{
+ IngestURL: server.url,
+ }
+ exporter := createExporter(t, config)
+
  t.Run("Test simple log data", func(t *testing.T) {
  var logs = createSimpleLogData(3)
- err = exp.pushLogData(context.Background(), logs)
+ err := exporter.pushLogData(context.Background(), logs)
  require.NoError(t, err)
  })
 
  t.Run("Test max message size", func(t *testing.T) {
  var logs = createSizedPayloadLogData(maxMessageSize)
- err = exp.pushLogData(context.Background(), logs)
+ err := exporter.pushLogData(context.Background(), logs)
  require.NoError(t, err)
  })
 
  t.Run("Test max body size", func(t *testing.T) {
  var logs = createMaxLogData()
- err = exp.pushLogData(context.Background(), logs)
+ err := exporter.pushLogData(context.Background(), logs)
  require.NoError(t, err)
  })
 }