Check for nil interface correctly

mongox/base/getid.go

@@ -6,6 +6,7 @@ import (
 	"go.mongodb.org/mongo-driver/bson/primitive"
 
 	"github.com/mainnika/mongox-go-driver/v2/mongox"
+	"github.com/mainnika/mongox-go-driver/v2/mongox/utils"
 )
 
 // GetID returns source document id
@@ -62,7 +63,7 @@ func getObjectOrPanic(source mongox.JSONBased) (id primitive.D) {
 func getInterfaceOrPanic(source mongox.InterfaceBased) (id interface{}) {
 
 	id = source.GetID()
-	if id != nil {
+	if !utils.IsNil(id) {
 		return id
 	}
 

mongox/base/getprotection.go

@@ -19,6 +19,9 @@ func GetProtection(source interface{}) *protection.Key {
 
 	for i := 0; i < numField; i++ {
 		field := el.Field(i)
+		if !field.CanInterface() {
+			continue
+		}
 
 		switch field.Interface().(type) {
 		case *protection.Key:

mongox/database/count.go

@@ -3,9 +3,9 @@ package database
 import (
 	"fmt"
 
-	"go.mongodb.org/mongo-driver/mongo"
 	"go.mongodb.org/mongo-driver/mongo/options"
 
+	"github.com/mainnika/mongox-go-driver/v2/mongox"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/query"
 )
 
@@ -21,7 +21,7 @@ func (d *Database) Count(target interface{}, filters ...interface{}) (int64, err
 	opts.Skip = composed.Skipper()
 
 	result, err := collection.CountDocuments(d.Context(), composed.M(), opts)
-	if err == mongo.ErrNoDocuments {
+	if err == mongox.ErrNoDocuments {
 		return 0, err
 	}
 	if err != nil {

mongox/database/database.go

@@ -8,7 +8,6 @@ import (
 	"strings"
 
 	"go.mongodb.org/mongo-driver/bson/primitive"
-	"go.mongodb.org/mongo-driver/mongo"
 	"go.mongodb.org/mongo-driver/mongo/options"
 
 	"github.com/mainnika/mongox-go-driver/v2/mongox"
@@ -17,13 +16,13 @@ import (
 
 // Database handler
 type Database struct {
-	client *mongo.Client
+	client *mongox.Client
 	dbname string
 	ctx    context.Context
 }
 
 // NewDatabase function creates new database instance with mongo client and empty context
-func NewDatabase(client *mongo.Client, dbname string) mongox.Database {
+func NewDatabase(client *mongox.Client, dbname string) mongox.Database {
 
 	db := &Database{}
 	db.client = client
@@ -33,13 +32,19 @@ func NewDatabase(client *mongo.Client, dbname string) mongox.Database {
 }
 
 // Client function returns a mongo client
-func (d *Database) Client() *mongo.Client {
+func (d *Database) Client() *mongox.Client {
 	return d.client
 }
 
 // Context function returns a context
-func (d *Database) Context() context.Context {
-	return d.ctx
+func (d *Database) Context() (ctx context.Context) {
+
+	ctx = d.ctx
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	return
 }
 
 // Name function returns a database name
@@ -67,7 +72,7 @@ func (d *Database) New(ctx context.Context) mongox.Database {
 //     base.ObjectID `bson:",inline" json:",inline" collection:"foobars"`
 // 	   ...
 // Will panic if there is no «collection» tag
-func (d *Database) GetCollectionOf(document interface{}) *mongo.Collection {
+func (d *Database) GetCollectionOf(document interface{}) *mongox.Collection {
 
 	el := reflect.TypeOf(document).Elem()
 	numField := el.NumField()
@@ -86,7 +91,7 @@ func (d *Database) GetCollectionOf(document interface{}) *mongo.Collection {
 	panic(fmt.Errorf("document %v does not have a collection tag", document))
 }
 
-func (d *Database) createSimpleLoad(target interface{}, composed *query.Query) (cursor *mongo.Cursor, err error) {
+func (d *Database) createSimpleLoad(target interface{}, composed *query.Query) (cursor *mongox.Cursor, err error) {
 
 	collection := d.GetCollectionOf(target)
 	opts := options.Find()
@@ -98,7 +103,7 @@ func (d *Database) createSimpleLoad(target interface{}, composed *query.Query) (
 	return collection.Find(d.Context(), composed.M(), opts)
 }
 
-func (d *Database) createAggregateLoad(target interface{}, composed *query.Query) (cursor *mongo.Cursor, err error) {
+func (d *Database) createAggregateLoad(target interface{}, composed *query.Query) (cursor *mongox.Cursor, err error) {
 
 	collection := d.GetCollectionOf(target)
 	opts := options.Aggregate()

mongox/database/deleteone.go

@@ -5,11 +5,12 @@ import (
 	"time"
 
 	"go.mongodb.org/mongo-driver/bson/primitive"
-	"go.mongodb.org/mongo-driver/mongo"
 	"go.mongodb.org/mongo-driver/mongo/options"
 
+	"github.com/mainnika/mongox-go-driver/v2/mongox"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/base"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/query"
+	"github.com/mainnika/mongox-go-driver/v2/mongox/utils"
 )
 
 // DeleteOne removes a document from a database and then returns it into target
@@ -22,7 +23,7 @@ func (d *Database) DeleteOne(target interface{}, filters ...interface{}) error {
 
 	opts.Sort = composed.Sorter()
 
-	if target != nil {
+	if !utils.IsNil(target) {
 		composed.And(primitive.M{"_id": base.GetID(target)})
 	}
 
@@ -38,7 +39,7 @@ func (d *Database) DeleteOne(target interface{}, filters ...interface{}) error {
 	}
 
 	err := result.Decode(target)
-	if err == mongo.ErrNoDocuments {
+	if err == mongox.ErrNoDocuments {
 		return err
 	}
 	if err != nil {

mongox/database/index.go

@@ -0,0 +1,134 @@
+package database
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+	"text/template"
+
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+)
+
+// IndexEnsure function ensures index in mongo collection of document
+//   `index:""` -- https://docs.mongodb.com/manual/indexes/#create-an-index
+//   `index:"-"` -- (descending)
+//   `index:"-,+foo,+-bar"` -- https://docs.mongodb.com/manual/core/index-compound
+//   `index:"-,+foo,+-bar,unique"` -- https://docs.mongodb.com/manual/core/index-unique
+//   `index:"-,+foo,+-bar,unique,allowNull"` -- https://docs.mongodb.com/manual/core/index-partial
+//   `index:"-,unique,allowNull,expireAfter=86400"` -- https://docs.mongodb.com/manual/core/index-ttl
+//   `index:"-,unique,allowNull,expireAfter={{.Expire}}"` -- evaluate index as a golang template with `cfg` arguments
+func (d *Database) IndexEnsure(cfg interface{}, document interface{}) error {
+
+	el := reflect.ValueOf(document).Elem().Type()
+	numField := el.NumField()
+	documents := d.GetCollectionOf(document)
+
+	for i := 0; i < numField; i++ {
+
+		field := el.Field(i)
+		tag := field.Tag
+
+		indexTag, ok := tag.Lookup("index")
+		if !ok {
+			continue
+		}
+		bsonTag, ok := tag.Lookup("bson")
+		if !ok {
+			return fmt.Errorf("bson tag is not defined for field:%v document:%v", field, document)
+		}
+
+		tmpBuffer := &bytes.Buffer{}
+		tpl, err := template.New("").Parse(indexTag)
+		if err != nil {
+			panic(fmt.Errorf("invalid prop template, %v", indexTag))
+		}
+		err = tpl.Execute(tmpBuffer, cfg)
+		if err != nil {
+			panic(fmt.Errorf("failed to evaluate prop template, %v", indexTag))
+		}
+
+		indexString := tmpBuffer.String()
+		indexValues := strings.Split(indexString, ",")
+		bsonValues := strings.Split(bsonTag, ",")
+
+		var f = false
+		var t = true
+		var key = bsonValues[0]
+		var name = fmt.Sprintf("%s_%s_", indexString, key)
+
+		if len(key) == 0 {
+			panic(fmt.Errorf("cannot evaluate index key"))
+		}
+
+		index := primitive.M{key: 1}
+		opts := &options.IndexOptions{
+			Background: &f,
+			Unique:     &f,
+			Name:       &name,
+		}
+
+		if indexValues[0] == "-" {
+			index[key] = -1
+		}
+
+		for _, prop := range indexValues[1:] {
+			var left string
+			var right string
+
+			pair := strings.SplitN(prop, "=", 2)
+			left = pair[0]
+			if len(pair) > 1 {
+				right = pair[1]
+			}
+
+			switch {
+			case left == "unique":
+				opts.Unique = &t
+
+			case left == "allowNull":
+				expression, isMap := opts.PartialFilterExpression.(primitive.M)
+				if !isMap || expression == nil {
+					expression = primitive.M{}
+				}
+
+				expression[key] = primitive.M{"$exists": true}
+				opts.PartialFilterExpression = expression
+
+			case left == "expireAfter":
+				expireAfter, err := strconv.Atoi(right)
+				if err != nil || expireAfter < 1 {
+					panic(fmt.Errorf("invalid expireAfter value, err: %w", err))
+				}
+
+				expireAfterInt32 := int32(expireAfter)
+				opts.ExpireAfterSeconds = &expireAfterInt32
+
+			case len(left) > 0 && left[0] == '+':
+				compoundValue := left[1:]
+				if len(compoundValue) == 0 {
+					panic(fmt.Errorf("invalid compound value"))
+				}
+
+				if compoundValue[0] == '-' {
+					index[compoundValue[1:]] = -1
+				} else {
+					index[compoundValue] = 1
+				}
+
+			default:
+				panic(fmt.Errorf("unsupported flag:%q in tag:%q of type:%s", prop, tag, el))
+			}
+		}
+
+		_, err = documents.Indexes().CreateOne(d.Context(), mongo.IndexModel{Keys: index, Options: opts})
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

mongox/database/index_test.go

@@ -0,0 +1,156 @@
+package database_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/mainnika/mongox-go-driver/v2/mongox-testing/database"
+	"github.com/mainnika/mongox-go-driver/v2/mongox/base/oidbased"
+)
+
+func TestDatabase_Ensure(t *testing.T) {
+
+	db, err := database.NewEphemeral("mongodb://localhost")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	testvalues := []struct {
+		doc      interface{}
+		settings map[string]interface{}
+		index    map[string]interface{}
+	}{
+		{
+			doc: &struct {
+				oidbased.Primary `bson:",inline" json:",inline" collection:"1"`
+
+				Foobar int `bson:"foobar" json:"foobar" index:"-,unique,allowNull,expireAfter=86400"`
+				Foo    int `bson:"foo" json:"foo"`
+				Bar    int `bson:"bar" json:"bar"`
+			}{},
+			index: map[string]interface{}{
+				"background":         false,
+				"expireAfterSeconds": int32(86400),
+				"key": map[string]interface{}{
+					"foobar": int32(-1),
+				},
+				"name": "-,unique,allowNull,expireAfter=86400_foobar_",
+				"partialFilterExpression": map[string]interface{}{
+					"foobar": map[string]interface{}{"$exists": true},
+				},
+				"unique": true,
+			},
+		},
+		{
+			doc: &struct {
+				oidbased.Primary `bson:",inline" json:",inline" collection:"2"`
+
+				Foobar int `bson:"foobar" json:"foobar" index:",unique"`
+			}{},
+			index: map[string]interface{}{
+				"background": false,
+				"key": map[string]interface{}{
+					"foobar": int32(1),
+				},
+				"name":   ",unique_foobar_",
+				"unique": true,
+			},
+		},
+		{
+			doc: &struct {
+				oidbased.Primary `bson:",inline" json:",inline" collection:"3"`
+
+				Foobar int `bson:"foobar" json:"foobar" index:"-,+foo,+-bar,unique,allowNull"`
+				Foo    int `bson:"foo" json:"foo"`
+				Bar    int `bson:"bar" json:"bar"`
+			}{},
+			index: map[string]interface{}{
+				"background": false,
+				"key": map[string]interface{}{
+					"foobar": int32(-1),
+					"foo":    int32(1),
+					"bar":    int32(-1),
+				},
+				"name": "-,+foo,+-bar,unique,allowNull_foobar_",
+				"partialFilterExpression": map[string]interface{}{
+					"foobar": map[string]interface{}{"$exists": true},
+				},
+				"unique": true,
+			},
+		},
+		{
+			doc: &struct {
+				oidbased.Primary `bson:",inline" json:",inline" collection:"4"`
+
+				Foobar int `bson:"foobar" json:"foobar" index:""`
+				Foo    int `bson:"foo" json:"foo"`
+				Bar    int `bson:"bar" json:"bar"`
+			}{},
+			index: map[string]interface{}{
+				"background": false,
+				"key": map[string]interface{}{
+					"foobar": int32(1),
+				},
+				"name": "_foobar_",
+			},
+		},
+		{
+			doc: &struct {
+				oidbased.Primary `bson:",inline" json:",inline" collection:"5"`
+
+				Foobar int `bson:"foobar" json:"foobar" index:"-"`
+				Foo    int `bson:"foo" json:"foo"`
+				Bar    int `bson:"bar" json:"bar"`
+			}{},
+			index: map[string]interface{}{
+				"background": false,
+				"key": map[string]interface{}{
+					"foobar": int32(-1),
+				},
+				"name": "-_foobar_",
+			},
+		},
+		{
+			doc: &struct {
+				oidbased.Primary `bson:",inline" json:",inline" collection:"1"`
+
+				Foobar int `bson:"foobar" json:"foobar" index:"-,unique,allowNull,expireAfter={{.Expire}}"`
+				Foo    int `bson:"foo" json:"foo"`
+				Bar    int `bson:"bar" json:"bar"`
+			}{},
+			settings: map[string]interface{}{
+				"Expire": 86400,
+			},
+			index: map[string]interface{}{
+				"background":         false,
+				"expireAfterSeconds": int32(86400),
+				"key": map[string]interface{}{
+					"foobar": int32(-1),
+				},
+				"name": "-,unique,allowNull,expireAfter=86400_foobar_",
+				"partialFilterExpression": map[string]interface{}{
+					"foobar": map[string]interface{}{"$exists": true},
+				},
+				"unique": true,
+			},
+		},
+	}
+
+	for _, tt := range testvalues {
+		err = db.IndexEnsure(tt.settings, tt.doc)
+		assert.NoError(t, err)
+
+		indexes, _ := db.GetCollectionOf(tt.doc).Indexes().List(db.Context())
+		index := new(map[string]interface{})
+
+		indexes.Next(db.Context()) // skip _id_
+		indexes.Next(db.Context())
+		indexes.Decode(&index)
+
+		for k, v := range tt.index {
+			assert.Equal(t, v, (*index)[k])
+		}
+	}
+}

mongox/database/loadarray.go

@@ -4,8 +4,7 @@ import (
 	"fmt"
 	"reflect"
 
-	"go.mongodb.org/mongo-driver/mongo"
-
+	"github.com/mainnika/mongox-go-driver/v2/mongox"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/base"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/query"
 )
@@ -36,7 +35,7 @@ func (d *Database) LoadArray(target interface{}, filters ...interface{}) error {
 	zeroElem := reflect.Zero(targetSliceElemT)
 	hasPreloader, _ := composed.Preloader()
 
-	var result *mongo.Cursor
+	var result *mongox.Cursor
 	var err error
 
 	if hasPreloader {

mongox/database/loadone.go

@@ -3,8 +3,7 @@ package database
 import (
 	"fmt"
 
-	"go.mongodb.org/mongo-driver/mongo"
-
+	"github.com/mainnika/mongox-go-driver/v2/mongox"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/base"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/query"
 )
@@ -15,7 +14,7 @@ func (d *Database) LoadOne(target interface{}, filters ...interface{}) error {
 	composed := query.Compose(append(filters, query.Limit(1))...)
 	hasPreloader, _ := composed.Preloader()
 
-	var result *mongo.Cursor
+	var result *mongox.Cursor
 	var err error
 
 	if hasPreloader {
@@ -32,7 +31,7 @@ func (d *Database) LoadOne(target interface{}, filters ...interface{}) error {
 		return err
 	}
 	if !hasNext {
-		return mongo.ErrNoDocuments
+		return mongox.ErrNoDocuments
 	}
 
 	base.Reset(target)

mongox/database/loadstream.go

@@ -3,8 +3,6 @@ package database
 import (
 	"fmt"
 
-	"go.mongodb.org/mongo-driver/mongo"
-
 	"github.com/mainnika/mongox-go-driver/v2/mongox"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/query"
 )
@@ -12,7 +10,7 @@ import (
 // LoadStream function loads documents one by one into a target channel
 func (d *Database) LoadStream(target interface{}, filters ...interface{}) (mongox.StreamLoader, error) {
 
-	var cursor *mongo.Cursor
+	var cursor *mongox.Cursor
 	var err error
 
 	composed := query.Compose(filters...)
@@ -27,7 +25,7 @@ func (d *Database) LoadStream(target interface{}, filters ...interface{}) (mongo
 		return nil, fmt.Errorf("can't create find result: %w", err)
 	}
 
-	l := &StreamLoader{Cursor: cursor, ctx: d.Context(), target: target}
+	l := &StreamLoader{cur: cursor, ctx: d.Context(), target: target}
 
 	return l, nil
 }

mongox/database/streamloader.go

@@ -4,14 +4,13 @@ import (
 	"context"
 	"fmt"
 
-	"go.mongodb.org/mongo-driver/mongo"
-
+	"github.com/mainnika/mongox-go-driver/v2/mongox"
 	"github.com/mainnika/mongox-go-driver/v2/mongox/base"
 )
 
 // StreamLoader is a controller for a database cursor
 type StreamLoader struct {
-	*mongo.Cursor
+	cur    *mongox.Cursor
 	ctx    context.Context
 	target interface{}
 }
@@ -19,18 +18,18 @@ type StreamLoader struct {
 // DecodeNext loads next documents to a target or returns an error
 func (l *StreamLoader) DecodeNext() error {
 
-	hasNext := l.Cursor.Next(l.ctx)
+	hasNext := l.cur.Next(l.ctx)
 
-	if l.Cursor.Err() != nil {
-		return l.Cursor.Err()
+	if l.cur.Err() != nil {
+		return l.cur.Err()
 	}
 	if !hasNext {
-		return mongo.ErrNoDocuments
+		return mongox.ErrNoDocuments
 	}
 
 	base.Reset(l.target)
 
-	err := l.Cursor.Decode(l.target)
+	err := l.cur.Decode(l.target)
 	if err != nil {
 		return fmt.Errorf("can't decode desult: %w", err)
 	}
@@ -43,7 +42,7 @@ func (l *StreamLoader) Decode() error {
 
 	base.Reset(l.target)
 
-	err := l.Cursor.Decode(l.target)
+	err := l.cur.Decode(l.target)
 	if err != nil {
 		return fmt.Errorf("can't decode desult: %w", err)
 	}
@@ -54,20 +53,27 @@ func (l *StreamLoader) Decode() error {
 // Next loads next documents but doesn't perform decoding
 func (l *StreamLoader) Next() error {
 
-	hasNext := l.Cursor.Next(l.ctx)
+	hasNext := l.cur.Next(l.ctx)
 
-	if l.Cursor.Err() != nil {
-		return l.Cursor.Err()
+	if l.cur.Err() != nil {
+		return l.cur.Err()
 	}
 	if !hasNext {
-		return mongo.ErrNoDocuments
+		return mongox.ErrNoDocuments
 	}
 
 	return nil
 }
 
+func (l *StreamLoader) Cursor() *mongox.Cursor {
+	return l.cur
+}
+
 // Close cursor
 func (l *StreamLoader) Close() error {
-
-	return l.Cursor.Close(l.ctx)
+	return l.cur.Close(l.ctx)
+}
+
+func (l *StreamLoader) Err() error {
+	return l.cur.Err()
 }

mongox/errors.go

@@ -0,0 +1,20 @@
+package mongox
+
+import (
+	"go.mongodb.org/mongo-driver/mongo"
+)
+
+// Reexported mongo errors
+var (
+	ErrMissingResumeToken  = mongo.ErrMissingResumeToken
+	ErrNilCursor           = mongo.ErrNilCursor
+	ErrUnacknowledgedWrite = mongo.ErrUnacknowledgedWrite
+	ErrClientDisconnected  = mongo.ErrClientDisconnected
+	ErrNilDocument         = mongo.ErrNilDocument
+	ErrEmptySlice          = mongo.ErrEmptySlice
+	ErrInvalidIndexValue   = mongo.ErrInvalidIndexValue
+	ErrNonStringIndexName  = mongo.ErrNonStringIndexName
+	ErrMultipleIndexDrop   = mongo.ErrMultipleIndexDrop
+	ErrWrongClient         = mongo.ErrWrongClient
+	ErrNoDocuments         = mongo.ErrNoDocuments
+)

mongox/mongox.go

@@ -7,13 +7,20 @@ import (
 	"go.mongodb.org/mongo-driver/mongo"
 )
 
+// Reexport basic mongo structs
+type (
+	Cursor     = mongo.Cursor
+	Client     = mongo.Client
+	Collection = mongo.Collection
+)
+
 // Database is the mongox database interface
 type Database interface {
-	Client() *mongo.Client
+	Client() *Client
 	Context() context.Context
 	Name() string
 	New(ctx context.Context) Database
-	GetCollectionOf(document interface{}) *mongo.Collection
+	GetCollectionOf(document interface{}) *Collection
 	Count(target interface{}, filters ...interface{}) (int64, error)
 	DeleteArray(target interface{}) error
 	DeleteOne(target interface{}, filters ...interface{}) error
@@ -21,10 +28,12 @@ type Database interface {
 	LoadOne(target interface{}, filters ...interface{}) error
 	LoadStream(target interface{}, filters ...interface{}) (StreamLoader, error)
 	SaveOne(source interface{}) error
+	IndexEnsure(cfg interface{}, document interface{}) error
 }
 
 // StreamLoader is a interface to control database cursor
 type StreamLoader interface {
+	Cursor() *Cursor
 	DecodeNext() error
 	Decode() error
 	Next() error

mongox/query/compose.go

@@ -7,6 +7,7 @@ import (
 	"go.mongodb.org/mongo-driver/bson/primitive"
 
 	"github.com/mainnika/mongox-go-driver/v2/mongox/base/protection"
+	"github.com/mainnika/mongox-go-driver/v2/mongox/utils"
 )
 
 // Compose is a function to compose filters into a single query
@@ -26,6 +27,10 @@ func Compose(filters ...interface{}) *Query {
 // Push applies single filter to a query
 func Push(q *Query, f interface{}) bool {
 
+	if utils.IsNil(f) {
+		return true
+	}
+
 	ok := false
 	ok = ok || applyBson(q, f)
 	ok = ok || applyLimit(q, f)
@@ -91,9 +96,6 @@ func applyProtection(q *Query, f interface{}) bool {
 		x = &f.X
 		v = &f.V
 	case *protection.Key:
-		if f == nil {
-			return false
-		}
 		x = &f.X
 		v = &f.V
 

mongox/utils/isnil.go

@@ -0,0 +1,21 @@
+package utils
+
+import (
+	"unsafe"
+)
+
+// IsNil function evaluates the interface value to nil
+func IsNil(i interface{}) bool {
+
+	type iface struct {
+		_   *interface{}
+		ptr unsafe.Pointer
+	}
+
+	unpacked := (*iface)(unsafe.Pointer(&i))
+	if unpacked.ptr == nil {
+		return true
+	}
+
+	return *(*unsafe.Pointer)(unpacked.ptr) == nil
+}

mongox/utils/isnil_test.go

@@ -0,0 +1,32 @@
+package utils
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsNil(t *testing.T) {
+
+	testvalues := []struct {
+		i     interface{}
+		isnil bool
+	}{
+		{nil, true},
+		{(*string)(nil), true},
+		{([]string)(nil), true},
+		{(map[string]string)(nil), true},
+		{(func() bool)(nil), true},
+		{(chan func() bool)(nil), true},
+		{"", true},
+		{0, true},
+		{append(([]string)(nil), ""), false},
+		{[]string{}, false},
+		{1, false},
+		{"1", false},
+	}
+
+	for _, tt := range testvalues {
+		assert.Equal(t, tt.isnil, IsNil(tt.i))
+	}
+}