Add test for batched http target requests

Adapted existing tests to suit implementation of batching tests without implementing the same/similar test logic again.

This adapts things to rely on acks to manage the waitgroup as opposed to the test server. Originally it was constructed that way because the test also tests the acking, so if that was broken the test might hang and it wouldn't be obvious that acking was responsible.

Got around that issue by adding a timeout to wait for the waitgroup. So now, if it doesn't ack enough, that timeout will occur, and if it acks too many times waitgroup will panic (which was the case already).

We could just as easily preserve the old behaviour and simply add a new test for this, if things are getting too complex here.

pkg/target/http_test.go

@@ -331,10 +331,12 @@ func TestHttpWrite_Simple(t *testing.T) {
 	testCases := []struct {
 		Name         string
 		ResponseCode int
+		BatchSize    int
 	}{
-		{Name: "200 response Code", ResponseCode: 200},
-		{Name: "201 response Code", ResponseCode: 201},
-		{Name: "226 response Code", ResponseCode: 226},
+		{Name: "200 response Code", ResponseCode: 200, BatchSize: 1},
+		{Name: "201 response Code", ResponseCode: 201, BatchSize: 1},
+		{Name: "226 response Code", ResponseCode: 226, BatchSize: 1},
+		{Name: "Batched", ResponseCode: 200, BatchSize: 20},
 	}
 
 	for _, tt := range testCases {
@@ -346,7 +348,7 @@ func TestHttpWrite_Simple(t *testing.T) {
 			server := createTestServerWithResponseCode(&results, tt.ResponseCode)
 			defer server.Close()
 
-			target, err := newHTTPTarget(server.URL, 5, 1, 1048576, 1048576, "application/json", "", "", "", "", "", "", true, false, "", "", "", "")
+			target, err := newHTTPTarget(server.URL, 5, tt.BatchSize, 1048576, 1048576, "application/json", "", "", "", "", "", "", true, false, "", "", "", "")
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -358,22 +360,29 @@ func TestHttpWrite_Simple(t *testing.T) {
 				wg.Done()
 			}
 
-			messages := testutil.GetTestMessages(501, "Hello Server!!", ackFunc)
-			wg.Add(501)
+			messages := testutil.GetTestMessages(200, "Hello Server!!", ackFunc)
+			wg.Add(200)
 			writeResult, err1 := target.Write(messages)
 
 			if ok := WaitForAcksWithTimeout(2*time.Second, &wg); !ok {
 				assert.Fail("Timed out waiting for acks")
 			}
 
 			assert.Nil(err1)
-			assert.Equal(501, len(writeResult.Sent))
-			assert.Equal(501, len(results))
+			assert.Equal(200, len(writeResult.Sent))
+			assert.Equal(200/tt.BatchSize, len(results))
 			for _, result := range results {
-				assert.Equal("[\"Hello Server!!\"]", string(result))
+				var res []string
+				err := json.Unmarshal(result, &res)
+				if err != nil {
+					assert.Fail("Request not an array as expected - got error unmarshalling: " + err.Error())
+				}
+				for _, r := range res {
+					assert.Equal("Hello Server!!", string(r))
+				}
 			}
 
-			assert.Equal(int64(501), ackOps)
+			assert.Equal(int64(200), ackOps)
 		})
 	}
 }