fix: enable adding multiple modifiers to the same interaction (#47)

There was a bug which meant that modifiers based on attempt count would
be overwitten because they were stored with the same key in the
modifiers map. We fix this by adding the attempt count to the key so
that now the keys are different and multiple modifiers can be added for
the same interaction based on attempt.

Co-authored-by: Andrea Rosa <[email protected]>

internal/app/concurrent_proxy_stage_test.go

@@ -10,11 +10,12 @@ import (
 	"testing"
 	"time"
 
-	"github.com/form3tech-oss/pact-proxy/internal/app/configuration"
-	"github.com/form3tech-oss/pact-proxy/pkg/pactproxy"
 	"github.com/pact-foundation/pact-go/dsl"
 	log "github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
+
+	"github.com/form3tech-oss/pact-proxy/internal/app/configuration"
+	"github.com/form3tech-oss/pact-proxy/pkg/pactproxy"
 )
 
 const (
@@ -256,6 +257,26 @@ func (s *ConcurrentProxyStage) the_second_user_response_should_have_the_right_st
 	return s
 }
 
+func (s *ConcurrentProxyStage) all_responses_should_have_the_expected_return_values() *ConcurrentProxyStage {
+	statuses := make(map[int]int)
+	bodies := make(map[string]int)
+	for _, res := range s.userResponses {
+		statuses[res.StatusCode] += 1
+		bd, err := io.ReadAll(res.Body)
+		s.assert.NoError(err)
+		res.Body.Close()
+		bodies[strings.ReplaceAll(strings.TrimSpace(string(bd)), "\"", "")] += 1
+	}
+	s.assert.Len(statuses, 3)
+	s.assert.Len(bodies, 2)
+	s.assert.Equal(1, statuses[http.StatusInternalServerError])
+	s.assert.Equal(1, statuses[http.StatusOK])
+	s.assert.Equal(1, statuses[http.StatusTeapot])
+	s.assert.Equal(2, bodies["{name:any}"])
+	s.assert.Equal(1, bodies["{name:Form3}"])
+	return s
+}
+
 func (s *ConcurrentProxyStage) all_the_address_responses_should_have_the_right_status_code() *ConcurrentProxyStage {
 	expectedLen := s.concurrentAddressRequestsPerSecond * int(s.concurrentAddressRequestsDuration/time.Second)
 	s.assert.Len(s.addressResponses, expectedLen, "number of address responses is not as expected")
@@ -280,3 +301,40 @@ func (s *ConcurrentProxyStage) the_proxy_waits_for_all_address_responses() *Conc
 
 	return s
 }
+
+func (s *ConcurrentProxyStage) the_concurrent_requests_are_sent_with_multiple_modifiers_for_same_interaction() {
+	err := s.pact.Verify(func() (err error) {
+		attempt := 1
+		s.proxy.ForInteraction(postNamePactWithAnyName).AddModifier("$.status", fmt.Sprintf("%d", http.StatusTeapot), &attempt)
+		attempt = 2
+		s.proxy.ForInteraction(postNamePactWithAnyName).AddModifier("$.status", fmt.Sprintf("%d", http.StatusInternalServerError), &attempt)
+		attempt = 3
+		s.proxy.ForInteraction(postNamePactWithAnyName).AddModifier("$.body.name", "Form3", &attempt)
+
+		wg := sync.WaitGroup{}
+
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			s.makeUserRequest()
+		}()
+
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			s.makeUserRequest()
+		}()
+
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			s.makeUserRequest()
+		}()
+
+		wg.Wait()
+
+		return nil
+	})
+
+	s.assert.NoError(err)
+}

internal/app/concurrent_proxy_test.go

@@ -34,6 +34,17 @@ func TestConcurrentRequestsForSameModifierBasedOnAttempt(t *testing.T) {
 		the_second_user_response_should_have_the_right_status_code_and_body()
 }
 
+func TestMultipleModifiersForSameInteraction(t *testing.T) {
+	given, when, then := NewConcurrentProxyStage(t)
+	given.
+		a_pact_that_allows_any_names()
+	when.
+		the_concurrent_requests_are_sent_with_multiple_modifiers_for_same_interaction()
+	then.
+		all_responses_should_have_the_expected_return_values()
+
+}
+
 func TestConcurrentRequestsWaitForAllPacts(t *testing.T) {
 	given, when, then := NewConcurrentProxyStage(t)
 

internal/app/pactproxy/modifier.go

@@ -22,7 +22,13 @@ type interactionModifiers struct {
 }
 
 func (im *interactionModifier) Key() string {
-	return strings.Join([]string{im.Interaction, im.Path}, "_")
+	var key string
+	if im.Attempt != nil {
+		key = strings.Join([]string{im.Interaction, im.Path, strconv.Itoa(*im.Attempt)}, "_")
+	} else {
+		key = strings.Join([]string{im.Interaction, im.Path}, "_")
+	}
+	return key
 }
 
 func (ims *interactionModifiers) AddModifier(modifier *interactionModifier) {