add responses delta

delta/delta.go

@@ -11,9 +11,9 @@ func Get(asymmetric bool, diffReport *diff.Diff) float64 {
 		return 0
 	}
 
-	delta := getEndpointsDelta(asymmetric, diffReport.EndpointsDiff)
+	deltaEndpoints := getEndpointsDelta(asymmetric, diffReport.EndpointsDiff)
 
-	return delta
+	return weightedAverage(deltaEndpoints)
 }
 
 func ratio(asymmetric bool, added int, deleted int, modifiedDelta float64, all int) float64 {
@@ -23,3 +23,18 @@ func ratio(asymmetric bool, added int, deleted int, modifiedDelta float64, all i
 
 	return (float64(added+deleted) + modifiedDelta) / float64(all)
 }
+
+type WeightedDelta struct {
+	delta  float64
+	weight int
+}
+
+func weightedAverage(weightedDeltas ...WeightedDelta) float64 {
+	dividend := 0.0
+	divisor := 0
+	for _, weightedDelta := range weightedDeltas {
+		dividend += weightedDelta.delta
+		divisor += weightedDelta.weight
+	}
+	return dividend / float64(divisor)
+}

delta/delta_test.go

@@ -119,3 +119,16 @@ func TestParameters(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, 0.25, delta.Get(true, d))
 }
+
+func TestResponses(t *testing.T) {
+	loader := openapi3.NewLoader()
+	s1, err := loader.LoadFromFile("../data/simple2.yaml")
+	require.NoError(t, err)
+
+	s2, err := loader.LoadFromFile("../data/simple4.yaml")
+	require.NoError(t, err)
+
+	d, err := diff.Get(diff.NewConfig(), s1, s2)
+	require.NoError(t, err)
+	require.Equal(t, 0.0625, delta.Get(true, d))
+}

delta/doc.go

@@ -1,5 +1,16 @@
 /*
 Package delta provides a distance function for OpenAPI Spec 3.
-The delta is a numeric value representing the distance between base and revision specs.
+The delta is a numeric value between 0 and 1 representing the distance between base and revision specs.
+
+For any spec, a: delta(a, a) = 0
+For any two specs, a and b, with no common elements: delta(a, b) = 1
+
+Symmetric mode:
+Delta considers both elements of base that are deleted in revision and elements of base that are added in revision.
+For any two specs, a and b: delta(a, b) = delta(b, a)
+
+Asymmetric mode:
+Delta only considers elements of base that are deleted in revision but not elements of base that are added in revision.
+For any two specs, a and b:  Delta(a, b) + Delta(b, a) = 1
 */
 package delta

delta/endpoints.go

@@ -4,9 +4,9 @@ import (
 	"github.com/tufin/oasdiff/diff"
 )
 
-func getEndpointsDelta(asymmetric bool, d *diff.EndpointsDiff) float64 {
+func getEndpointsDelta(asymmetric bool, d *diff.EndpointsDiff) WeightedDelta {
 	if d.Empty() {
-		return 0
+		return WeightedDelta{}
 	}
 
 	added := len(d.Added)
@@ -17,7 +17,10 @@ func getEndpointsDelta(asymmetric bool, d *diff.EndpointsDiff) float64 {
 
 	modifiedDelta := coefficient * getModifiedEndpointsDelta(asymmetric, d.Modified)
 
-	return ratio(asymmetric, added, deleted, modifiedDelta, all)
+	return WeightedDelta{
+		delta:  ratio(asymmetric, added, deleted, modifiedDelta, all),
+		weight: 1,
+	}
 }
 
 func getModifiedEndpointsDelta(asymmetric bool, d diff.ModifiedEndpoints) float64 {
@@ -34,7 +37,8 @@ func getModifiedEndpointDelta(asymmetric bool, d *diff.MethodDiff) float64 {
 	}
 
 	// TODO: consider additional elements of MethodDiff
-	delta := getParametersDelta(asymmetric, d.ParametersDiff)
+	paramsDelta := getParametersDelta(asymmetric, d.ParametersDiff)
+	responsesDelta := getResponsesDelta(asymmetric, d.ResponsesDiff)
 
-	return delta
+	return weightedAverage(paramsDelta, responsesDelta)
 }

delta/parameters.go

@@ -4,9 +4,9 @@ import (
 	"github.com/tufin/oasdiff/diff"
 )
 
-func getParametersDelta(asymmetric bool, d *diff.ParametersDiffByLocation) float64 {
+func getParametersDelta(asymmetric bool, d *diff.ParametersDiffByLocation) WeightedDelta {
 	if d.Empty() {
-		return 0
+		return WeightedDelta{}
 	}
 
 	added := d.Added.Len()
@@ -18,5 +18,8 @@ func getParametersDelta(asymmetric bool, d *diff.ParametersDiffByLocation) float
 	// TODO: drill down into modified
 	modifiedDelta := coefficient * float64(modified)
 
-	return ratio(asymmetric, added, deleted, modifiedDelta, all)
+	return WeightedDelta{
+		delta:  ratio(asymmetric, added, deleted, modifiedDelta, all),
+		weight: all,
+	}
 }

delta/responses.go

@@ -0,0 +1,25 @@
+package delta
+
+import (
+	"github.com/tufin/oasdiff/diff"
+)
+
+func getResponsesDelta(asymmetric bool, d *diff.ResponsesDiff) WeightedDelta {
+	if d.Empty() {
+		return WeightedDelta{}
+	}
+
+	added := d.Added.Len()
+	deleted := d.Deleted.Len()
+	modified := len(d.Modified)
+	unchanged := d.Unchanged.Len()
+	all := added + deleted + modified + unchanged
+
+	// TODO: drill down into modified
+	modifiedDelta := coefficient * float64(modified)
+
+	return WeightedDelta{
+		delta:  ratio(asymmetric, added, deleted, modifiedDelta, all),
+		weight: all,
+	}
+}

diff/responses_diff.go

@@ -9,9 +9,10 @@ import (
 
 // ResponsesDiff describes the changes between a pair of sets of response objects: https://swagger.io/specification/#responses-object
 type ResponsesDiff struct {
-	Added    utils.StringList  `json:"added,omitempty" yaml:"added,omitempty"`
-	Deleted  utils.StringList  `json:"deleted,omitempty" yaml:"deleted,omitempty"`
-	Modified ModifiedResponses `json:"modified,omitempty" yaml:"modified,omitempty"`
+	Added     utils.StringList  `json:"added,omitempty" yaml:"added,omitempty"`
+	Deleted   utils.StringList  `json:"deleted,omitempty" yaml:"deleted,omitempty"`
+	Modified  ModifiedResponses `json:"modified,omitempty" yaml:"modified,omitempty"`
+	Unchanged utils.StringList  `json:"unchanged,omitempty" yaml:"unchanged,omitempty"`
 }
 
 // Empty indicates whether a change was found in this element
@@ -30,9 +31,10 @@ type ModifiedResponses map[string]*ResponseDiff
 
 func newResponsesDiff() *ResponsesDiff {
 	return &ResponsesDiff{
-		Added:    utils.StringList{},
-		Deleted:  utils.StringList{},
-		Modified: ModifiedResponses{},
+		Added:     utils.StringList{},
+		Deleted:   utils.StringList{},
+		Modified:  ModifiedResponses{},
+		Unchanged: utils.StringList{},
 	}
 }
 
@@ -73,7 +75,9 @@ func getResponsesDiffInternal(config *Config, state *state, responses1, response
 			if err != nil {
 				return nil, err
 			}
-			if !diff.Empty() {
+			if diff.Empty() {
+				result.Unchanged = append(result.Unchanged, responseValue1)
+			} else {
 				result.Modified[responseValue1] = diff
 			}
 		} else {