feat: multiple responses responder

response.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/jarcoal/httpmock/internal"
 )
@@ -125,6 +126,48 @@ func ResponderFromResponse(resp *http.Response) Responder {
 	}
 }
 
+// ResponderFromMultipleResponses wraps an *http.Response list in a Responder.
+//
+// Each response will be returned in the order of the provided list.
+// If the responder is called more than the size of the provided list, an error
+// will be thrown.
+//
+// Be careful, except for responses generated by httpmock
+// (NewStringResponse and NewBytesResponse functions) for which there
+// is no problems, it is the caller responsibility to ensure the
+// response body can be read several times and concurrently if needed,
+// as it is shared among all Responder returned responses.
+//
+// For home-made responses, NewRespBodyFromString and
+// NewRespBodyFromBytes functions can be used to produce response
+// bodies that can be read several times and concurrently.
+func ResponderFromMultipleResponses(responses []*http.Response, fn ...func(...interface{})) Responder {
+	responseIndex := 0
+	mutex := sync.Mutex{}
+	return func(req *http.Request) (*http.Response, error) {
+		mutex.Lock()
+		defer mutex.Unlock()
+		defer func() { responseIndex++ }()
+		if responseIndex >= len(responses) {
+			err := internal.StackTracer{
+				Err: fmt.Errorf("not enough responses provided: responder called %d time(s) but %d response(s) provided", responseIndex+1, len(responses)),
+			}
+			if len(fn) > 0 {
+				err.CustomFn = fn[0]
+			}
+			return nil, err
+		}
+		res := *responses[responseIndex]
+		// Our stuff: generate a new io.ReadCloser instance sharing the same buffer
+		if body, ok := responses[responseIndex].Body.(*dummyReadCloser); ok {
+			res.Body = body.copy()
+		}
+
+		res.Request = req
+		return &res, nil
+	}
+}
+
 // NewErrorResponder creates a Responder that returns an empty request and the
 // given error. This can be used to e.g. imitate more deep http errors for the
 // client.

response_test.go

@@ -53,6 +53,76 @@ func TestResponderFromResponse(t *testing.T) {
 	}
 }
 
+func TestResponderFromResponses(t *testing.T) {
+	jsonResponse, err := NewJsonResponse(200, map[string]string{"test": "toto"})
+	if err != nil {
+		t.Errorf("NewJsonResponse failed: %s", err)
+	}
+
+	responder := ResponderFromMultipleResponses(
+		[]*http.Response{
+			jsonResponse,
+			NewStringResponse(200, "hello world"),
+		},
+	)
+
+	req, err := http.NewRequest(http.MethodGet, testURL, nil)
+	if err != nil {
+		t.Fatal("Error creating request")
+	}
+	response1, err := responder(req)
+	if err != nil {
+		t.Error("Error should be nil")
+	}
+
+	testURLWithQuery := testURL + "?a=1"
+	req, err = http.NewRequest(http.MethodGet, testURLWithQuery, nil)
+	if err != nil {
+		t.Fatal("Error creating request")
+	}
+	response2, err := responder(req)
+	if err != nil {
+		t.Error("Error should be nil")
+	}
+
+	// Body should be the same for both responses
+	assertBody(t, response1, `{"test":"toto"}`)
+	assertBody(t, response2, "hello world")
+
+	// Request should be non-nil and different for each response
+	if response1.Request != nil && response2.Request != nil {
+		if response1.Request.URL.String() != testURL {
+			t.Errorf("Expected request url %s, got: %s", testURL, response1.Request.URL.String())
+		}
+		if response2.Request.URL.String() != testURLWithQuery {
+			t.Errorf("Expected request url %s, got: %s", testURLWithQuery, response2.Request.URL.String())
+		}
+	} else {
+		t.Error("response.Request should not be nil")
+	}
+
+	// ensure we can't call the responder more than the number of responses it embeds
+	_, err = responder(req)
+	if err == nil {
+		t.Error("Error should not be nil")
+	} else if err.Error() != "not enough responses provided: responder called 3 time(s) but 2 response(s) provided" {
+		t.Error("Invalid error message")
+	}
+
+	// fn usage
+	responder = ResponderFromMultipleResponses([]*http.Response{}, func(args ...interface{}) {})
+	_, err = responder(req)
+	if err == nil {
+		t.Error("Error should not be nil")
+	} else if err.Error() != "not enough responses provided: responder called 1 time(s) but 0 response(s) provided" {
+		t.Errorf("Invalid error message")
+	} else if ne, ok := err.(internal.StackTracer); !ok {
+		t.Errorf(`err type mismatch, got %T, expected internal.StackTracer`, err)
+	} else if ne.CustomFn == nil {
+		t.Error(`ne.CustomFn should not be nil`)
+	}
+}
+
 func TestNewNotFoundResponder(t *testing.T) {
 	responder := NewNotFoundResponder(func(args ...interface{}) {})