Copy tests from cockroach uint128

Changed add and sub functions to worth with multiple uint128 instead
of uint128+uint64

uint128/uint128_test.go

@@ -0,0 +1,126 @@
+// Copyright 2017 The Cockroach Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+// implied. See the License for the specific language governing
+// permissions and limitations under the License.
+
+package uint128
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestBytes(t *testing.T) {
+	b := []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
+
+	i := FromBytes(b)
+
+	if !bytes.Equal(i.GetBytes(), b) {
+		t.Errorf("incorrect bytes representation for num: %v", i)
+	}
+}
+
+func TestString(t *testing.T) {
+	s := "a95e31998f38490651c02b97c7f2acca"
+
+	i, _ := FromString(s)
+
+	if s != i.String() {
+		t.Errorf("incorrect string representation for num: %v", i)
+	}
+}
+
+func TestStringTooLong(t *testing.T) {
+	s := "ba95e31998f38490651c02b97c7f2acca"
+
+	_, err := FromString(s)
+
+	if err == nil || !strings.Contains(err.Error(), "too large") {
+		t.Error("did not get error for encoding invalid uint128 string")
+	}
+}
+
+func TestStringInvalidHex(t *testing.T) {
+	s := "bazz95e31998849051c02b97c7f2acca"
+
+	_, err := FromString(s)
+
+	if err == nil || !strings.Contains(err.Error(), "could not decode") {
+		t.Error("did not get error for encoding invalid uint128 string")
+	}
+}
+
+func TestSub(t *testing.T) {
+	testData := []struct {
+		num      Uint128
+		expected Uint128
+		sub      Uint128
+	}{
+		{Uint128{0, 1}, Uint128{0, 0}, Uint128{0, 1}},
+		{Uint128{18446744073709551615, 18446744073709551615}, Uint128{18446744073709551615, 18446744073709551614}, Uint128{0, 1}},
+		{Uint128{0, 18446744073709551615}, Uint128{0, 18446744073709551614}, Uint128{0, 1}},
+		{Uint128{18446744073709551615, 0}, Uint128{18446744073709551614, 18446744073709551615}, Uint128{0, 1}},
+		{Uint128{18446744073709551615, 0}, Uint128{18446744073709551614, 18446744073709551591}, Uint128{0, 25}},
+	}
+
+	for _, test := range testData {
+		res := test.num.Sub(test.sub)
+		if res != test.expected {
+			t.Errorf("expected: %v - %d = %v but got %v", test.num, test.sub, test.expected, res)
+		}
+	}
+}
+
+func TestAdd(t *testing.T) {
+	testData := []struct {
+		num      Uint128
+		expected Uint128
+		add      Uint128
+	}{
+		{Uint128{0, 0}, Uint128{0, 1}, Uint128{0, 1}},
+		{Uint128{18446744073709551615, 18446744073709551614}, Uint128{18446744073709551615, 18446744073709551615}, Uint128{0, 1}},
+		{Uint128{0, 18446744073709551615}, Uint128{1, 0}, Uint128{0, 1}},
+		{Uint128{18446744073709551615, 0}, Uint128{18446744073709551615, 1}, Uint128{0, 1}},
+		{Uint128{0, 18446744073709551615}, Uint128{1, 24}, Uint128{0, 25}},
+	}
+
+	for _, test := range testData {
+		res := test.num.Add(test.add)
+		if res != test.expected {
+			t.Errorf("expected: %v + %d = %v but got %v", test.num, test.add, test.expected, res)
+		}
+	}
+}
+
+func TestEqual(t *testing.T) {
+	testData := []struct {
+		u1       Uint128
+		u2       Uint128
+		expected bool
+	}{
+		{Uint128{0, 0}, Uint128{0, 1}, false},
+		{Uint128{1, 0}, Uint128{0, 1}, false},
+		{Uint128{18446744073709551615, 18446744073709551614}, Uint128{18446744073709551615, 18446744073709551615}, false},
+		{Uint128{0, 1}, Uint128{0, 1}, true},
+		{Uint128{0, 0}, Uint128{0, 0}, true},
+		{Uint128{314, 0}, Uint128{314, 0}, true},
+		{Uint128{18446744073709551615, 18446744073709551615}, Uint128{18446744073709551615, 18446744073709551615}, true},
+	}
+
+	for _, test := range testData {
+
+		if actual := test.u1.Equal(test.u2); actual != test.expected {
+			t.Errorf("expected: %v.Equal(%v) expected %v but got %v", test.u1, test.u2, test.expected, actual)
+		}
+	}
+}