Improve JSON marshaling of a11y metadata

pkg/manifest/a11y.go

@@ -17,7 +17,7 @@ type A11y struct {
 	Certification         *A11yCertification        `json:"certification,omitempty"`        // Certification of accessible publications.
 	Summary               string                    `json:"summary,omitempty"`              // A human-readable summary of specific accessibility features or deficiencies, consistent with the other accessibility metadata but expressing subtleties such as "short descriptions are present but long descriptions will be needed for non-visual users" or "short descriptions are present and no long descriptions are needed."
 	AccessModes           []A11yAccessMode          `json:"accessMode,omitempty"`           // The human sensory perceptual system or cognitive faculty through which a person may process or perceive information.
-	AccessModesSufficient [][]A11yPrimaryAccessMode `json:"accessModeSufficient,omitempty"` //  A list of single or combined accessModes that are sufficient to understand all the intellectual content of a resource.
+	AccessModesSufficient A11yPrimaryAccessModeList `json:"accessModeSufficient,omitempty"` // A list of single or combined accessModes that are sufficient to understand all the intellectual content of a resource.
 	Features              []A11yFeature             `json:"feature,omitempty"`              // Content features of the resource, such as accessible media, alternatives and supported enhancements for accessibility.
 	Hazards               []A11yHazard              `json:"hazard,omitempty"`               // A characteristic of the described resource that is physiologically dangerous to some users.
 	Exemptions            []A11yExemption           `json:"exemption,omitempty"`            // Justifications for non-conformance based on exemptions in a given jurisdiction.
@@ -28,7 +28,7 @@ func NewA11y() A11y {
 	return A11y{
 		ConformsTo:            A11yProfileList{},
 		AccessModes:           []A11yAccessMode{},
-		AccessModesSufficient: [][]A11yPrimaryAccessMode{},
+		AccessModesSufficient: A11yPrimaryAccessModeList{},
 		Features:              []A11yFeature{},
 		Hazards:               []A11yHazard{},
 		Exemptions:            []A11yExemption{},
@@ -109,7 +109,7 @@ func A11yFromJSON(rawJSON map[string]interface{}) (*A11y, error) {
 	}
 	a.AccessModes = A11yAccessModesFromStrings(accessModes)
 
-	ams := [][]A11yPrimaryAccessMode{}
+	ams := A11yPrimaryAccessModeList{}
 	if amsJSON, ok := rawJSON["accessModeSufficient"].([]interface{}); ok {
 		for _, l := range amsJSON {
 			strings, err := parseSliceOrString(l, true)
@@ -229,6 +229,15 @@ func (p A11yProfile) Compare(other A11yProfile) int {
 
 type A11yProfileList []A11yProfile
 
+func (l A11yProfileList) MarshalJSON() ([]byte, error) {
+	if len(l) == 1 {
+		return json.Marshal(l[0])
+	}
+
+	type alias A11yProfileList
+	return json.Marshal(alias(l))
+}
+
 func (l A11yProfileList) Sort() {
 	if len(l) <= 1 {
 		return
@@ -300,6 +309,17 @@ func A11yAccessModesFromStrings(strings []string) []A11yAccessMode {
 // A11yPrimaryAccessMode is a human primary sensory perceptual system or cognitive faculty through which a person may process or perceive information.
 type A11yPrimaryAccessMode string
 
+type A11yPrimaryAccessModeList [][]A11yPrimaryAccessMode
+
+func (l A11yPrimaryAccessModeList) MarshalJSON() ([]byte, error) {
+	if len(l) == 1 && len(l[0]) == 1 {
+		return json.Marshal(l[0][0])
+	}
+
+	type alias A11yPrimaryAccessModeList
+	return json.Marshal(alias(l))
+}
+
 const (
 	// Indicates that auditory perception is necessary to consume the information.
 	A11yPrimaryAccessModeAuditory A11yPrimaryAccessMode = "auditory"

pkg/manifest/a11y_test.go

@@ -45,7 +45,7 @@ func TestA11yUnmarshalFullJSON(t *testing.T) {
 			A11yAccessModeAuditory,
 			A11yAccessModeChartOnVisual,
 		},
-		AccessModesSufficient: [][]A11yPrimaryAccessMode{
+		AccessModesSufficient: A11yPrimaryAccessModeList{
 			{
 				A11yPrimaryAccessModeVisual,
 				A11yPrimaryAccessModeTactile,
@@ -110,7 +110,7 @@ func TestA11yUnmarshalAccessModeSufficientContainingBothStringsAndArrays(t *test
 	var m A11y
 	require.NoError(t, json.Unmarshal([]byte(`{"accessModeSufficient": ["auditory", ["visual", "tactile"], [], "visual"]}`), &m))
 	var e A11y = NewA11y()
-	e.AccessModesSufficient = [][]A11yPrimaryAccessMode{
+	e.AccessModesSufficient = A11yPrimaryAccessModeList{
 		{A11yPrimaryAccessModeAuditory},
 		{A11yPrimaryAccessModeVisual, A11yPrimaryAccessModeTactile},
 		{A11yPrimaryAccessModeVisual},
@@ -122,7 +122,7 @@ func TestA11yMarshalMinimalJSON(t *testing.T) {
 	m := A11y{
 		ConformsTo:            []A11yProfile{},
 		AccessModes:           []A11yAccessMode{},
-		AccessModesSufficient: [][]A11yPrimaryAccessMode{},
+		AccessModesSufficient: A11yPrimaryAccessModeList{},
 		Features:              []A11yFeature{},
 		Hazards:               []A11yHazard{},
 		Exemptions:            []A11yExemption{},
@@ -148,7 +148,7 @@ func TestA11yMarshalFullJSON(t *testing.T) {
 			A11yAccessModeAuditory,
 			A11yAccessModeChartOnVisual,
 		},
-		AccessModesSufficient: [][]A11yPrimaryAccessMode{
+		AccessModesSufficient: A11yPrimaryAccessModeList{
 			{A11yPrimaryAccessModeAuditory},
 			{
 				A11yPrimaryAccessModeVisual,
@@ -177,3 +177,33 @@ func TestA11yMarshalFullJSON(t *testing.T) {
 		[]byte(`{"conformsTo":["http://www.idpf.org/epub/a11y/accessibility-20170105.html#wcag-a","https://profile2"],"certification":{"certifiedBy":"company1","credential":"credential1","report":"https://report1"},"summary":"Summary","accessMode":["auditory","chartOnVisual"],"accessModeSufficient":[["auditory"],["visual","tactile"],["visual"]],"feature":["readingOrder","alternativeText"],"hazard":["flashing","motionSimulation"],"exemption":["eaa-fundamental-alteration","eaa-microenterprise"]}`),
 	)
 }
+
+func TestA11yMarshalConformsToSingleValue(t *testing.T) {
+	m := A11y{
+		ConformsTo: []A11yProfile{
+			EPUBA11y11WCAG22AA,
+		},
+	}
+	data, err := json.Marshal(m)
+	require.NoError(t, err)
+	assert.Equal(
+		t,
+		[]byte(`{"conformsTo":"https://www.w3.org/TR/epub-a11y-11#wcag-2.2-aa"}`),
+		data,
+	)
+}
+
+func TestA11yMarshalAccessModeSufficientSingleValue(t *testing.T) {
+	m := A11y{
+		AccessModesSufficient: A11yPrimaryAccessModeList{
+			{A11yPrimaryAccessModeTextual},
+		},
+	}
+	data, err := json.Marshal(m)
+	require.NoError(t, err)
+	assert.Equal(
+		t,
+		[]byte(`{"accessModeSufficient":"textual"}`),
+		data,
+	)
+}

pkg/manifest/metadata_test.go

@@ -297,7 +297,7 @@ func TestMetadataFullJSON(t *testing.T) {
 		],
 		"title": {"en": "Title", "fr": "Titre"},
 		"subtitle": {"en": "Subtitle", "fr": "Sous-titre"},
-		"accessibility": {"conformsTo": ["http://www.idpf.org/epub/a11y/accessibility-20170105.html#wcag-aa"]},
+		"accessibility": {"conformsTo": "http://www.idpf.org/epub/a11y/accessibility-20170105.html#wcag-aa"},
 		"tdm": {"policy": "https://provider.com/policies/policy.json", "reservation": "all"},
 		"modified": "2001-01-01T12:36:27.123Z",
 		"published": "2001-01-02T12:36:27Z",

pkg/parser/epub/metadata.go

@@ -819,8 +819,8 @@ func valuesToAccessModes(values []string) []manifest.A11yAccessMode {
 	return am
 }
 
-func valuesToAccessModesSufficient(values []string) [][]manifest.A11yPrimaryAccessMode {
-	ams := make([][]manifest.A11yPrimaryAccessMode, 0, len(values))
+func valuesToAccessModesSufficient(values []string) manifest.A11yPrimaryAccessModeList {
+	ams := make(manifest.A11yPrimaryAccessModeList, 0, len(values))
 	for _, v := range values {
 		c := a11yAccessModesSufficient(v)
 		if len(c) > 0 {

pkg/parser/epub/metadata_test.go

@@ -319,7 +319,7 @@ func TestMetadataEPUB2Accessibility(t *testing.T) {
 	}
 	e.Summary = "The publication contains structural and page navigation."
 	e.AccessModes = []manifest.A11yAccessMode{manifest.A11yAccessModeTextual, manifest.A11yAccessModeVisual}
-	e.AccessModesSufficient = [][]manifest.A11yPrimaryAccessMode{
+	e.AccessModesSufficient = manifest.A11yPrimaryAccessModeList{
 		{manifest.A11yPrimaryAccessModeTextual},
 		{manifest.A11yPrimaryAccessModeTextual, manifest.A11yPrimaryAccessModeVisual},
 	}
@@ -351,7 +351,7 @@ func TestMetadataEPUB3Accessibility(t *testing.T) {
 	}
 	e.Summary = "The publication contains structural and page navigation."
 	e.AccessModes = []manifest.A11yAccessMode{manifest.A11yAccessModeTextual, manifest.A11yAccessModeVisual}
-	e.AccessModesSufficient = [][]manifest.A11yPrimaryAccessMode{
+	e.AccessModesSufficient = manifest.A11yPrimaryAccessModeList{
 		{manifest.A11yPrimaryAccessModeTextual},
 		{manifest.A11yPrimaryAccessModeTextual, manifest.A11yPrimaryAccessModeVisual},
 	}
@@ -372,7 +372,7 @@ func TestMetadataEPUB3AccessibilityRefines(t *testing.T) {
 		CertifiedBy: "Standard Ebooks",
 	}
 	e.AccessModes = manifest.A11yAccessModesFromStrings([]string{"textual"})
-	e.AccessModesSufficient = [][]manifest.A11yPrimaryAccessMode{
+	e.AccessModesSufficient = manifest.A11yPrimaryAccessModeList{
 		a11yAccessModesSufficient("textual"),
 	}
 	e.Features = valuesToA11yFeatures([]string{"readingOrder", "structuralNavigation", "tableOfContents", "unlocked"})

pkg/streamer/a11y_infer_test.go

@@ -29,7 +29,7 @@ func TestReturnsAdditionalInferredA11yMetadata(t *testing.T) {
 
 	inferreddA11y := manifest.NewA11y()
 	inferreddA11y.AccessModes = []manifest.A11yAccessMode{manifest.A11yAccessModeTextual}
-	inferreddA11y.AccessModesSufficient = [][]manifest.A11yPrimaryAccessMode{{manifest.A11yPrimaryAccessModeTextual}}
+	inferreddA11y.AccessModesSufficient = manifest.A11yPrimaryAccessModeList{{manifest.A11yPrimaryAccessModeTextual}}
 
 	res, err := inferA11yMetadataInPublicationManifest(context.TODO(), pub.New(m, nil, nil), nil)
 	require.NoError(t, err)