add test for marshal

Signed-off-by: Ashutosh Kumar <sonasingh46@gmail.com>

Author: sonasingh46

types/nullable_test.go

@@ -2,6 +2,7 @@ package types
 
 import (
 	"encoding/json"
+	"fmt"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"testing"
@@ -349,3 +350,58 @@ func TestMixed(t *testing.T) {
 		})
 	}
 }
+
+func TestNullable_MarshalJSON(t *testing.T) {
+	type testCase struct {
+		name string
+		obj  SimpleInt
+		want []byte
+	}
+	tests := []testCase{
+		{
+			name: "when obj is not set",
+			want: []byte(`{"replicaCount":0}`),
+		},
+		{
+			name: "when obj is explicitly set to a specific value",
+			obj: SimpleInt{
+				ReplicaCount: Nullable[int]{
+					Value: 5,
+					Set:   true,
+					Null:  false,
+				},
+			},
+			want: []byte(`{"replicaCount":5}`),
+		},
+		{
+			name: "when obj is explicitly set to zero value",
+			obj: SimpleInt{
+				ReplicaCount: Nullable[int]{
+					Value: 0,
+					Set:   true,
+					Null:  false,
+				},
+			},
+			want: []byte(`{"replicaCount":0}`),
+		},
+		{
+			name: "when obj is explicitly set to null value",
+			obj: SimpleInt{
+				ReplicaCount: Nullable[int]{
+					Value: 0,
+					Set:   true,
+					Null:  true,
+				},
+			},
+			want: []byte(`{"replicaCount":null}`),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := json.Marshal(tt.obj)
+			fmt.Println(string(got))
+			require.NoError(t, err)
+			assert.Equalf(t, tt.want, got, "MarshalJSON()")
+		})
+	}
+}