diff --git a/core/mapping/unmarshaler_test.go b/core/mapping/unmarshaler_test.go
index 9e91432d..fe4c4375 100644
--- a/core/mapping/unmarshaler_test.go
+++ b/core/mapping/unmarshaler_test.go
@@ -2,6 +2,7 @@ package mapping
 
 import (
 	"encoding/json"
+	"fmt"
 	"strconv"
 	"strings"
 	"testing"
@@ -467,6 +468,85 @@ func TestUnmarshalIntSliceFromString(t *testing.T) {
 	ast.Equal(2, v.Values[1])
 }
 
+func TestUnmarshalIntMapFromString(t *testing.T) {
+	var v struct {
+		Sort map[string]int `key:"sort"`
+	}
+	m := map[string]interface{}{
+		"sort": `{"value":12345,"zeroVal":0,"nullVal":null}`,
+	}
+
+	ast := assert.New(t)
+	ast.Nil(UnmarshalKey(m, &v))
+	ast.Equal(3, len(v.Sort))
+	ast.Equal(12345, v.Sort["value"])
+	ast.Equal(0, v.Sort["zeroVal"])
+	ast.Equal(0, v.Sort["nullVal"])
+}
+
+func TestUnmarshalBoolMapFromString(t *testing.T) {
+	var v struct {
+		Sort map[string]bool `key:"sort"`
+	}
+	m := map[string]interface{}{
+		"sort": `{"value":true,"zeroVal":false,"nullVal":null}`,
+	}
+
+	ast := assert.New(t)
+	ast.Nil(UnmarshalKey(m, &v))
+	ast.Equal(3, len(v.Sort))
+	ast.Equal(true, v.Sort["value"])
+	ast.Equal(false, v.Sort["zeroVal"])
+	ast.Equal(false, v.Sort["nullVal"])
+}
+
+type CustomStringer string
+
+type UnsupportedStringer string
+
+func (c CustomStringer) String() string {
+	return fmt.Sprintf("{%s}", string(c))
+}
+
+func TestUnmarshalStringMapFromStringer(t *testing.T) {
+	var v struct {
+		Sort map[string]string `key:"sort"`
+	}
+	m := map[string]interface{}{
+		"sort": CustomStringer(`"value":"ascend","emptyStr":""`),
+	}
+
+	ast := assert.New(t)
+	ast.Nil(UnmarshalKey(m, &v))
+	ast.Equal(2, len(v.Sort))
+	ast.Equal("ascend", v.Sort["value"])
+	ast.Equal("", v.Sort["emptyStr"])
+}
+
+func TestUnmarshalStringMapFromUnsupportedType(t *testing.T) {
+	var v struct {
+		Sort map[string]string `key:"sort"`
+	}
+	m := map[string]interface{}{
+		"sort": UnsupportedStringer(`{"value":"ascend","emptyStr":""}`),
+	}
+
+	ast := assert.New(t)
+	ast.NotNil(UnmarshalKey(m, &v))
+}
+
+func TestUnmarshalStringMapFromNotSettableValue(t *testing.T) {
+	var v struct {
+		sort map[string]string `key:"sort"`
+	}
+	m := map[string]interface{}{
+		"sort": `{"value":"ascend","emptyStr":""}`,
+	}
+
+	ast := assert.New(t)
+	ast.NotNil(UnmarshalKey(m, &v))
+}
+
 func TestUnmarshalStringMapFromString(t *testing.T) {
 	var v struct {
 		Sort map[string]string `key:"sort"`
@@ -482,6 +562,32 @@ func TestUnmarshalStringMapFromString(t *testing.T) {
 	ast.Equal("", v.Sort["emptyStr"])
 }
 
+func TestUnmarshalStructMapFromString(t *testing.T) {
+	var v struct {
+		Filter map[string]struct {
+			Field1 bool     `json:"field1"`
+			Field2 int64    `json:"field2,string"`
+			Field3 string   `json:"field3"`
+			Field4 *string  `json:"field4"`
+			Field5 []string `json:"field5"`
+		} `key:"filter"`
+	}
+	m := map[string]interface{}{
+		"filter": `{"obj":{"field1":true,"field2":"1573570455447539712","field3":"this is a string",
+			"field4":"this is a string pointer","field5":["str1","str2"]}}`,
+	}
+
+	ast := assert.New(t)
+	ast.Nil(UnmarshalKey(m, &v))
+	ast.Equal(1, len(v.Filter))
+	ast.NotNil(v.Filter["obj"])
+	ast.Equal(true, v.Filter["obj"].Field1)
+	ast.Equal(int64(1573570455447539712), v.Filter["obj"].Field2)
+	ast.Equal("this is a string", v.Filter["obj"].Field3)
+	ast.Equal("this is a string pointer", *v.Filter["obj"].Field4)
+	ast.ElementsMatch([]string{"str1", "str2"}, v.Filter["obj"].Field5)
+}
+
 func TestUnmarshalStringSliceMapFromString(t *testing.T) {
 	var v struct {
 		Filter map[string][]string `key:"filter"`