func TestHashJsonMarshal(t *testing.T) {
        tests := []struct {
                hash Hash
                err  error
        }{
                // Genesis hash.
                {
                        mainNetGenesisHash,
                        nil,
                },
        }

        unexpectedErrStr := "TestHashJsonMarshal #%d got an unexpected error: %v"
        unexpectedResultStr := "TestHashJsonMarshal #%d got: %v want: %v"
        for i, test := range tests {
                bytes, err := test.hash.MarshalJSON()
                if err != nil {
                        t.Errorf(unexpectedErrStr, i, err)
                        continue
                }

                got := new(Hash)
                err = json.Unmarshal(bytes, got)
                if err != nil {
                        t.Errorf(unexpectedErrStr, i, err)
                        continue
                }

                if !test.hash.IsEqual(got) {
                        t.Errorf(unexpectedResultStr, i, got, &test.hash)
                        continue
                }
        }
}