fix: Export missing attributes in Settings.ToMap

The following attributes were missing in the result Map returned by the
Settings.ToMap function:
 * `enableRules`
 * `ignorePlurals`
 * `sortFacetValuesBy`

Also, some fields may not have been properly transformed because the
Settings.clean function was not called to clean some fields with sane
defaults.

This commits fixes all the aformentioned issues and adds a test to
ensure that any new field added to the Settings struct will make the
tests fail in not handled in the Settings.ToMap function.

algoliasearch/index_test.go

@@ -1,10 +1,12 @@
 package algoliasearch
 
 import (
+	"reflect"
 	"sort"
 	"sync"
 	"testing"
 	"time"
+	"unicode"
 
 	"github.com/stretchr/testify/require"
 )
@@ -1072,6 +1074,31 @@ func TestSettingsToMap(t *testing.T) {
 	settingsAreEqual(t, settingsBefore, settingsAfter)
 }
 
+func TestSettingsToMap_allRequiredFieldsArePresent(t *testing.T) {
+	var settings Settings
+
+	m := settings.ToMap()
+
+	s := reflect.ValueOf(&settings).Elem()
+	tt := s.Type()
+
+	for i := 0; i < s.NumField(); i++ {
+		// Skip []string-type fields because those are discarded to avoid
+		// sending useless data to the API.
+		if tt.Field(i).Type.String() == "[]string" {
+			continue
+		}
+
+		expectedSettingName := tt.Field(i).Name
+		tmp := []rune(expectedSettingName)
+		tmp[0] = unicode.ToLower(tmp[0])
+		expectedSettingName = string(tmp)
+
+		_, ok := m[expectedSettingName]
+		require.True(t, ok, "should find '%s' setting in the result map", expectedSettingName)
+	}
+}
+
 func facetHitSliceAreEqual(fs1, fs2 []FacetHit) bool {
 	if len(fs1) != len(fs2) {
 		return false

algoliasearch/types_settings.go

@@ -80,12 +80,20 @@ func (s *Settings) clean() {
 	if s.MaxFacetHits == 0 {
 		s.MaxFacetHits = 10
 	}
+
+	if s.SortFacetValuesBy == "" {
+		s.SortFacetValuesBy = "count"
+	}
 }
 
 // ToMap produces a `Map` corresponding to the `Settings struct`. It should
 // only be used when it's needed to pass a `Settings struct` to `SetSettings`,
 // typically when one needs to copy settings between two indices.
 func (s *Settings) ToMap() Map {
+	// Guarantee that interface{}-typed fields and default values are correctly
+	// set.
+	s.clean()
+
 	// Add all fields except:
 	//  - Distinct float64 or bool
 	//  - IgnorePlurals []interface{} or bool
@@ -117,9 +125,11 @@ func (s *Settings) ToMap() Map {
 		"attributesToHighlight":             s.AttributesToHighlight,
 		"attributesToRetrieve":              s.AttributesToRetrieve,
 		"attributesToSnippet":               s.AttributesToSnippet,
+		"enableRules":                       s.EnableRules,
 		"highlightPostTag":                  s.HighlightPostTag,
 		"highlightPreTag":                   s.HighlightPreTag,
 		"hitsPerPage":                       s.HitsPerPage,
+		"ignorePlurals":                     s.IgnorePlurals,
 		"maxFacetHits":                      s.MaxFacetHits,
 		"maxValuesPerFacet":                 s.MaxValuesPerFacet,
 		"minProximity":                      s.MinProximity,
@@ -132,6 +142,7 @@ func (s *Settings) ToMap() Map {
 		"responseFields":                    s.ResponseFields,
 		"restrictHighlightAndSnippetArrays": s.RestrictHighlightAndSnippetArrays,
 		"snippetEllipsisText":               s.SnippetEllipsisText,
+		"sortFacetValuesBy":                 s.SortFacetValuesBy,
 		"typoTolerance":                     s.TypoTolerance,
 	}