Handle ArrayBuffer conversion from http.batch()

This is a breaking change part of #1020.

js/modules/k6/http/request.go

@@ -451,6 +451,7 @@ func (h *HTTP) Batch(ctx context.Context, reqsV goja.Value) (goja.Value, error)
 	errs := httpext.MakeBatchRequests(
 		ctx, batchReqs, reqCount,
 		int(state.Options.Batch.Int64), int(state.Options.BatchPerHost.Int64),
+		processResponse,
 	)
 
 	for i := 0; i < reqCount; i++ {

js/modules/k6/http/request_test.go

@@ -1722,6 +1722,27 @@ func TestResponseTypes(t *testing.T) {
 			}
 		}
 		http.post("HTTPBIN_URL/compare-bin", respBin.body);
+
+		// Check ArrayBuffer response
+		var respBin = http.get("HTTPBIN_URL/get-bin", { responseType: "binary" }).body;
+		if (respBin.byteLength !== expBinLength) {
+			throw new Error("response body length should be '" + expBinLength + "' but was '" + respBin.byteLength + "'");
+		}
+
+		// Check ArrayBuffer responses with http.batch()
+		var responses = http.batch([
+			["GET", "HTTPBIN_URL/get-bin", null, { responseType: "binary" }],
+			["GET", "HTTPBIN_URL/get-bin", null, { responseType: "binary" }],
+		]);
+		if (responses.length != 2) {
+			throw new Error("expected 2 responses, received " + responses.length);
+		}
+		for (var i = 0; i < responses.length; i++) {
+			if (responses[i].body.byteLength !== expBinLength) {
+				throw new Error("response body length should be '"
+					+ expBinLength + "' but was '" + responses[i].body.byteLength + "'");
+			}
+		}
 	`))
 	assert.NoError(t, err)
 

lib/netext/httpext/batch.go

@@ -42,10 +42,13 @@ type BatchParsedHTTPRequest struct {
 // pre-initialized. In addition, each processed request would emit either a nil
 // value, or an error, via the returned errors channel. The goroutines exit when
 // the requests channel is closed.
+// The processResponse callback can be used to modify the response, e.g.
+// to replace the body.
 func MakeBatchRequests(
 	ctx context.Context,
 	requests []BatchParsedHTTPRequest,
 	reqCount, globalLimit, perHostLimit int,
+	processResponse func(context.Context, *Response, ResponseType),
 ) <-chan error {
 	workers := globalLimit
 	if reqCount < workers {
@@ -62,6 +65,7 @@ func MakeBatchRequests(
 
 		resp, err := MakeRequest(ctx, req.ParsedHTTPRequest)
 		if resp != nil {
+			processResponse(ctx, resp, req.ParsedHTTPRequest.ResponseType)
 			*req.Response = *resp
 		}
 		result <- err