package packfile
import (
"math/rand"
. "gopkg.in/check.v1"
)
type DeltaSuite struct {
testCases []deltaTest
}
var _ = Suite(&DeltaSuite{})
type deltaTest struct {
description string
base []piece
target []piece
}
func (s *DeltaSuite) SetUpSuite(c *C) {
s.testCases = []deltaTest{{
description: "distinct file",
base: []piece{{"0", 300}},
target: []piece{{"2", 200}},
}, {
description: "same file",
base: []piece{{"1", 3000}},
target: []piece{{"1", 3000}},
}, {
description: "small file",
base: []piece{{"1", 3}},
target: []piece{{"1", 3}, {"0", 1}},
}, {
description: "big file",
base: []piece{{"1", 300000}},
target: []piece{{"1", 30000}, {"0", 1000000}},
}, {
description: "add elements before",
base: []piece{{"0", 200}},
target: []piece{{"1", 300}, {"0", 200}},
}, {
description: "add 10 times more elements at the end",
base: []piece{{"1", 300}, {"0", 200}},
target: []piece{{"0", 2000}},
}, {
description: "add elements between",
base: []piece{{"0", 400}},
target: []piece{{"0", 200}, {"1", 200}, {"0", 200}},
}, {
description: "add elements after",
base: []piece{{"0", 200}},
target: []piece{{"0", 200}, {"1", 200}},
}, {
description: "modify elements at the end",
base: []piece{{"1", 300}, {"0", 200}},
target: []piece{{"0", 100}},
}, {
description: "complex modification",
base: []piece{{"0", 3}, {"1", 40}, {"2", 30}, {"3", 2},
{"4", 400}, {"5", 23}},
target: []piece{{"1", 30}, {"2", 20}, {"7", 40}, {"4", 400},
{"5", 10}},
}, {
description: "A copy operation bigger than 64kb",
base: []piece{{bigRandStr, 1}, {"1", 200}},
target: []piece{{bigRandStr, 1}},
}}
}
var bigRandStr = randStringBytes(100 * 1024)
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
func randBytes(n int) []byte {
b := make([]byte, n)
for i := range b {
b[i] = letterBytes[rand.Intn(len(letterBytes))]
}
return b
}
func randStringBytes(n int) string {
return string(randBytes(n))
}
func (s *DeltaSuite) TestAddDelta(c *C) {
for _, t := range s.testCases {
baseBuf := genBytes(t.base)
targetBuf := genBytes(t.target)
delta := DiffDelta(baseBuf, targetBuf)
result, err := PatchDelta(baseBuf, delta)
c.Log("Executing test case:", t.description)
c.Assert(err, IsNil)
c.Assert(result, DeepEquals, targetBuf)
}
}
func (s *DeltaSuite) TestIncompleteDelta(c *C) {
for _, t := range s.testCases {
c.Log("Incomplete delta on:", t.description)
baseBuf := genBytes(t.base)
targetBuf := genBytes(t.target)
delta := DiffDelta(baseBuf, targetBuf)
delta = delta[:len(delta)-2]
result, err := PatchDelta(baseBuf, delta)
c.Assert(err, NotNil)
c.Assert(result, IsNil)
}
// check nil input too
result, err := PatchDelta(nil, nil)
c.Assert(err, NotNil)
c.Assert(result, IsNil)
}
func (s *DeltaSuite) TestMaxCopySizeDelta(c *C) {
baseBuf := randBytes(maxCopySize)
targetBuf := baseBuf[0:]
targetBuf = append(targetBuf, byte(1))
delta := DiffDelta(baseBuf, targetBuf)
result, err := PatchDelta(baseBuf, delta)
c.Assert(err, IsNil)
c.Assert(result, DeepEquals, targetBuf)
}
