Clarify Invalid value and bring back the tests

Author: Antoine Pelisse

value/less_test.go

@@ -20,6 +20,8 @@ import (
 	"testing"
 )
 
+var InvalidValue = struct{}{}
+
 func TestValueLess(t *testing.T) {
 	table := []struct {
 		name string
@@ -29,6 +31,39 @@ func TestValueLess(t *testing.T) {
 		eq   bool
 	}{
 		{
+			name: "Invalid-1",
+			a:    InvalidValue,
+			b:    InvalidValue,
+			eq:   true,
+		}, {
+			name: "Invalid-2",
+			a:    1.,
+			b:    InvalidValue,
+		}, {
+			name: "Invalid-3",
+			a:    1,
+			b:    InvalidValue,
+		}, {
+			name: "Invalid-4",
+			a:    "aoeu",
+			b:    InvalidValue,
+		}, {
+			name: "Invalid-5",
+			a:    true,
+			b:    InvalidValue,
+		}, {
+			name: "Invalid-6",
+			a:    []interface{}{},
+			b:    InvalidValue,
+		}, {
+			name: "Invalid-7",
+			a:    map[string]interface{}{},
+			b:    InvalidValue,
+		}, {
+			name: "Invalid-8",
+			a:    nil,
+			b:    InvalidValue,
+		}, {
 			name: "Float-1",
 			a:    1.14,
 			b:    3.14,

value/value.go

@@ -31,7 +31,9 @@ var (
 	writePool = jsoniter.NewStream(jsoniter.ConfigCompatibleWithStandardLibrary, nil, 1024).Pool()
 )
 
-// A Value corresponds to an 'atom' in the schema.
+// A Value corresponds to an 'atom' in the schema. It should return true
+// for at least one of the IsXXX methods below, or the value is
+// considered "invalid"
 type Value interface {
 	// IsMap returns true if the Value is a Map, false otherwise.
 	IsMap() bool