smart diff to testutil.GatherAndCompare (#998)

* added smart diff to testutil.GatherAndCompare

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>

* v2 testuitls added for better diff

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>

* replaced CollectAndCompare to CollectAndCompareV2 in testutil_test

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>

* renamed methods from v2 to withT

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>

* replaced testify with custom diff func

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>

* difflib GetUnifiedDiffString added with test

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>

* license meta data added to file

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>

* moved difflib to internal

Signed-off-by: Sourik Ghosh <sourikghosh31@gmail.com>
This commit is contained in:
Sourik Ghosh 2022-04-13 23:08:05 +05:30 committed by GitHub
parent 0c691ed35f
commit cd90f33be8
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5 changed files with 992 additions and 20 deletions

1
go.mod
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@ -3,6 +3,7 @@ module github.com/prometheus/client_golang
require (
github.com/beorn7/perks v1.0.1
github.com/cespare/xxhash/v2 v2.1.2
github.com/davecgh/go-spew v1.1.1
github.com/golang/protobuf v1.5.2
github.com/jpillora/backoff v1.0.0 // indirect
github.com/json-iterator/go v1.1.12

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@ -0,0 +1,649 @@
// Copyright 2022 The Prometheus 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.
//
// It provides tools to compare sequences of strings and generate textual diffs.
//
// Maintaining `GetUnifiedDiffString` here because original repository
// (https://github.com/pmezard/go-difflib) is no loger maintained.
package internal
import (
"bufio"
"bytes"
"fmt"
"io"
"strings"
)
func min(a, b int) int {
if a < b {
return a
}
return b
}
func max(a, b int) int {
if a > b {
return a
}
return b
}
func calculateRatio(matches, length int) float64 {
if length > 0 {
return 2.0 * float64(matches) / float64(length)
}
return 1.0
}
type Match struct {
A int
B int
Size int
}
type OpCode struct {
Tag byte
I1 int
I2 int
J1 int
J2 int
}
// SequenceMatcher compares sequence of strings. The basic
// algorithm predates, and is a little fancier than, an algorithm
// published in the late 1980's by Ratcliff and Obershelp under the
// hyperbolic name "gestalt pattern matching". The basic idea is to find
// the longest contiguous matching subsequence that contains no "junk"
// elements (R-O doesn't address junk). The same idea is then applied
// recursively to the pieces of the sequences to the left and to the right
// of the matching subsequence. This does not yield minimal edit
// sequences, but does tend to yield matches that "look right" to people.
//
// SequenceMatcher tries to compute a "human-friendly diff" between two
// sequences. Unlike e.g. UNIX(tm) diff, the fundamental notion is the
// longest *contiguous* & junk-free matching subsequence. That's what
// catches peoples' eyes. The Windows(tm) windiff has another interesting
// notion, pairing up elements that appear uniquely in each sequence.
// That, and the method here, appear to yield more intuitive difference
// reports than does diff. This method appears to be the least vulnerable
// to synching up on blocks of "junk lines", though (like blank lines in
// ordinary text files, or maybe "<P>" lines in HTML files). That may be
// because this is the only method of the 3 that has a *concept* of
// "junk" <wink>.
//
// Timing: Basic R-O is cubic time worst case and quadratic time expected
// case. SequenceMatcher is quadratic time for the worst case and has
// expected-case behavior dependent in a complicated way on how many
// elements the sequences have in common; best case time is linear.
type SequenceMatcher struct {
a []string
b []string
b2j map[string][]int
IsJunk func(string) bool
autoJunk bool
bJunk map[string]struct{}
matchingBlocks []Match
fullBCount map[string]int
bPopular map[string]struct{}
opCodes []OpCode
}
func NewMatcher(a, b []string) *SequenceMatcher {
m := SequenceMatcher{autoJunk: true}
m.SetSeqs(a, b)
return &m
}
func NewMatcherWithJunk(a, b []string, autoJunk bool,
isJunk func(string) bool) *SequenceMatcher {
m := SequenceMatcher{IsJunk: isJunk, autoJunk: autoJunk}
m.SetSeqs(a, b)
return &m
}
// Set two sequences to be compared.
func (m *SequenceMatcher) SetSeqs(a, b []string) {
m.SetSeq1(a)
m.SetSeq2(b)
}
// Set the first sequence to be compared. The second sequence to be compared is
// not changed.
//
// SequenceMatcher computes and caches detailed information about the second
// sequence, so if you want to compare one sequence S against many sequences,
// use .SetSeq2(s) once and call .SetSeq1(x) repeatedly for each of the other
// sequences.
//
// See also SetSeqs() and SetSeq2().
func (m *SequenceMatcher) SetSeq1(a []string) {
if &a == &m.a {
return
}
m.a = a
m.matchingBlocks = nil
m.opCodes = nil
}
// Set the second sequence to be compared. The first sequence to be compared is
// not changed.
func (m *SequenceMatcher) SetSeq2(b []string) {
if &b == &m.b {
return
}
m.b = b
m.matchingBlocks = nil
m.opCodes = nil
m.fullBCount = nil
m.chainB()
}
func (m *SequenceMatcher) chainB() {
// Populate line -> index mapping
b2j := map[string][]int{}
for i, s := range m.b {
indices := b2j[s]
indices = append(indices, i)
b2j[s] = indices
}
// Purge junk elements
m.bJunk = map[string]struct{}{}
if m.IsJunk != nil {
junk := m.bJunk
for s, _ := range b2j {
if m.IsJunk(s) {
junk[s] = struct{}{}
}
}
for s, _ := range junk {
delete(b2j, s)
}
}
// Purge remaining popular elements
popular := map[string]struct{}{}
n := len(m.b)
if m.autoJunk && n >= 200 {
ntest := n/100 + 1
for s, indices := range b2j {
if len(indices) > ntest {
popular[s] = struct{}{}
}
}
for s, _ := range popular {
delete(b2j, s)
}
}
m.bPopular = popular
m.b2j = b2j
}
func (m *SequenceMatcher) isBJunk(s string) bool {
_, ok := m.bJunk[s]
return ok
}
// Find longest matching block in a[alo:ahi] and b[blo:bhi].
//
// If IsJunk is not defined:
//
// Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
// alo <= i <= i+k <= ahi
// blo <= j <= j+k <= bhi
// and for all (i',j',k') meeting those conditions,
// k >= k'
// i <= i'
// and if i == i', j <= j'
//
// In other words, of all maximal matching blocks, return one that
// starts earliest in a, and of all those maximal matching blocks that
// start earliest in a, return the one that starts earliest in b.
//
// If IsJunk is defined, first the longest matching block is
// determined as above, but with the additional restriction that no
// junk element appears in the block. Then that block is extended as
// far as possible by matching (only) junk elements on both sides. So
// the resulting block never matches on junk except as identical junk
// happens to be adjacent to an "interesting" match.
//
// If no blocks match, return (alo, blo, 0).
func (m *SequenceMatcher) findLongestMatch(alo, ahi, blo, bhi int) Match {
// CAUTION: stripping common prefix or suffix would be incorrect.
// E.g.,
// ab
// acab
// Longest matching block is "ab", but if common prefix is
// stripped, it's "a" (tied with "b"). UNIX(tm) diff does so
// strip, so ends up claiming that ab is changed to acab by
// inserting "ca" in the middle. That's minimal but unintuitive:
// "it's obvious" that someone inserted "ac" at the front.
// Windiff ends up at the same place as diff, but by pairing up
// the unique 'b's and then matching the first two 'a's.
besti, bestj, bestsize := alo, blo, 0
// find longest junk-free match
// during an iteration of the loop, j2len[j] = length of longest
// junk-free match ending with a[i-1] and b[j]
j2len := map[int]int{}
for i := alo; i != ahi; i++ {
// look at all instances of a[i] in b; note that because
// b2j has no junk keys, the loop is skipped if a[i] is junk
newj2len := map[int]int{}
for _, j := range m.b2j[m.a[i]] {
// a[i] matches b[j]
if j < blo {
continue
}
if j >= bhi {
break
}
k := j2len[j-1] + 1
newj2len[j] = k
if k > bestsize {
besti, bestj, bestsize = i-k+1, j-k+1, k
}
}
j2len = newj2len
}
// Extend the best by non-junk elements on each end. In particular,
// "popular" non-junk elements aren't in b2j, which greatly speeds
// the inner loop above, but also means "the best" match so far
// doesn't contain any junk *or* popular non-junk elements.
for besti > alo && bestj > blo && !m.isBJunk(m.b[bestj-1]) &&
m.a[besti-1] == m.b[bestj-1] {
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
}
for besti+bestsize < ahi && bestj+bestsize < bhi &&
!m.isBJunk(m.b[bestj+bestsize]) &&
m.a[besti+bestsize] == m.b[bestj+bestsize] {
bestsize += 1
}
// Now that we have a wholly interesting match (albeit possibly
// empty!), we may as well suck up the matching junk on each
// side of it too. Can't think of a good reason not to, and it
// saves post-processing the (possibly considerable) expense of
// figuring out what to do with it. In the case of an empty
// interesting match, this is clearly the right thing to do,
// because no other kind of match is possible in the regions.
for besti > alo && bestj > blo && m.isBJunk(m.b[bestj-1]) &&
m.a[besti-1] == m.b[bestj-1] {
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
}
for besti+bestsize < ahi && bestj+bestsize < bhi &&
m.isBJunk(m.b[bestj+bestsize]) &&
m.a[besti+bestsize] == m.b[bestj+bestsize] {
bestsize += 1
}
return Match{A: besti, B: bestj, Size: bestsize}
}
// Return list of triples describing matching subsequences.
//
// Each triple is of the form (i, j, n), and means that
// a[i:i+n] == b[j:j+n]. The triples are monotonically increasing in
// i and in j. It's also guaranteed that if (i, j, n) and (i', j', n') are
// adjacent triples in the list, and the second is not the last triple in the
// list, then i+n != i' or j+n != j'. IOW, adjacent triples never describe
// adjacent equal blocks.
//
// The last triple is a dummy, (len(a), len(b), 0), and is the only
// triple with n==0.
func (m *SequenceMatcher) GetMatchingBlocks() []Match {
if m.matchingBlocks != nil {
return m.matchingBlocks
}
var matchBlocks func(alo, ahi, blo, bhi int, matched []Match) []Match
matchBlocks = func(alo, ahi, blo, bhi int, matched []Match) []Match {
match := m.findLongestMatch(alo, ahi, blo, bhi)
i, j, k := match.A, match.B, match.Size
if match.Size > 0 {
if alo < i && blo < j {
matched = matchBlocks(alo, i, blo, j, matched)
}
matched = append(matched, match)
if i+k < ahi && j+k < bhi {
matched = matchBlocks(i+k, ahi, j+k, bhi, matched)
}
}
return matched
}
matched := matchBlocks(0, len(m.a), 0, len(m.b), nil)
// It's possible that we have adjacent equal blocks in the
// matching_blocks list now.
nonAdjacent := []Match{}
i1, j1, k1 := 0, 0, 0
for _, b := range matched {
// Is this block adjacent to i1, j1, k1?
i2, j2, k2 := b.A, b.B, b.Size
if i1+k1 == i2 && j1+k1 == j2 {
// Yes, so collapse them -- this just increases the length of
// the first block by the length of the second, and the first
// block so lengthened remains the block to compare against.
k1 += k2
} else {
// Not adjacent. Remember the first block (k1==0 means it's
// the dummy we started with), and make the second block the
// new block to compare against.
if k1 > 0 {
nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
}
i1, j1, k1 = i2, j2, k2
}
}
if k1 > 0 {
nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
}
nonAdjacent = append(nonAdjacent, Match{len(m.a), len(m.b), 0})
m.matchingBlocks = nonAdjacent
return m.matchingBlocks
}
// Return list of 5-tuples describing how to turn a into b.
//
// Each tuple is of the form (tag, i1, i2, j1, j2). The first tuple
// has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the
// tuple preceding it, and likewise for j1 == the previous j2.
//
// The tags are characters, with these meanings:
//
// 'r' (replace): a[i1:i2] should be replaced by b[j1:j2]
//
// 'd' (delete): a[i1:i2] should be deleted, j1==j2 in this case.
//
// 'i' (insert): b[j1:j2] should be inserted at a[i1:i1], i1==i2 in this case.
//
// 'e' (equal): a[i1:i2] == b[j1:j2]
func (m *SequenceMatcher) GetOpCodes() []OpCode {
if m.opCodes != nil {
return m.opCodes
}
i, j := 0, 0
matching := m.GetMatchingBlocks()
opCodes := make([]OpCode, 0, len(matching))
for _, m := range matching {
// invariant: we've pumped out correct diffs to change
// a[:i] into b[:j], and the next matching block is
// a[ai:ai+size] == b[bj:bj+size]. So we need to pump
// out a diff to change a[i:ai] into b[j:bj], pump out
// the matching block, and move (i,j) beyond the match
ai, bj, size := m.A, m.B, m.Size
tag := byte(0)
if i < ai && j < bj {
tag = 'r'
} else if i < ai {
tag = 'd'
} else if j < bj {
tag = 'i'
}
if tag > 0 {
opCodes = append(opCodes, OpCode{tag, i, ai, j, bj})
}
i, j = ai+size, bj+size
// the list of matching blocks is terminated by a
// sentinel with size 0
if size > 0 {
opCodes = append(opCodes, OpCode{'e', ai, i, bj, j})
}
}
m.opCodes = opCodes
return m.opCodes
}
// Isolate change clusters by eliminating ranges with no changes.
//
// Return a generator of groups with up to n lines of context.
// Each group is in the same format as returned by GetOpCodes().
func (m *SequenceMatcher) GetGroupedOpCodes(n int) [][]OpCode {
if n < 0 {
n = 3
}
codes := m.GetOpCodes()
if len(codes) == 0 {
codes = []OpCode{{'e', 0, 1, 0, 1}}
}
// Fixup leading and trailing groups if they show no changes.
if codes[0].Tag == 'e' {
c := codes[0]
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
codes[0] = OpCode{c.Tag, max(i1, i2-n), i2, max(j1, j2-n), j2}
}
if codes[len(codes)-1].Tag == 'e' {
c := codes[len(codes)-1]
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
codes[len(codes)-1] = OpCode{c.Tag, i1, min(i2, i1+n), j1, min(j2, j1+n)}
}
nn := n + n
groups := [][]OpCode{}
group := []OpCode{}
for _, c := range codes {
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
// End the current group and start a new one whenever
// there is a large range with no changes.
if c.Tag == 'e' && i2-i1 > nn {
group = append(group, OpCode{c.Tag, i1, min(i2, i1+n),
j1, min(j2, j1+n)})
groups = append(groups, group)
group = []OpCode{}
i1, j1 = max(i1, i2-n), max(j1, j2-n)
}
group = append(group, OpCode{c.Tag, i1, i2, j1, j2})
}
if len(group) > 0 && !(len(group) == 1 && group[0].Tag == 'e') {
groups = append(groups, group)
}
return groups
}
// Return a measure of the sequences' similarity (float in [0,1]).
//
// Where T is the total number of elements in both sequences, and
// M is the number of matches, this is 2.0*M / T.
// Note that this is 1 if the sequences are identical, and 0 if
// they have nothing in common.
//
// .Ratio() is expensive to compute if you haven't already computed
// .GetMatchingBlocks() or .GetOpCodes(), in which case you may
// want to try .QuickRatio() or .RealQuickRation() first to get an
// upper bound.
func (m *SequenceMatcher) Ratio() float64 {
matches := 0
for _, m := range m.GetMatchingBlocks() {
matches += m.Size
}
return calculateRatio(matches, len(m.a)+len(m.b))
}
// Return an upper bound on ratio() relatively quickly.
//
// This isn't defined beyond that it is an upper bound on .Ratio(), and
// is faster to compute.
func (m *SequenceMatcher) QuickRatio() float64 {
// viewing a and b as multisets, set matches to the cardinality
// of their intersection; this counts the number of matches
// without regard to order, so is clearly an upper bound
if m.fullBCount == nil {
m.fullBCount = map[string]int{}
for _, s := range m.b {
m.fullBCount[s] = m.fullBCount[s] + 1
}
}
// avail[x] is the number of times x appears in 'b' less the
// number of times we've seen it in 'a' so far ... kinda
avail := map[string]int{}
matches := 0
for _, s := range m.a {
n, ok := avail[s]
if !ok {
n = m.fullBCount[s]
}
avail[s] = n - 1
if n > 0 {
matches += 1
}
}
return calculateRatio(matches, len(m.a)+len(m.b))
}
// Return an upper bound on ratio() very quickly.
//
// This isn't defined beyond that it is an upper bound on .Ratio(), and
// is faster to compute than either .Ratio() or .QuickRatio().
func (m *SequenceMatcher) RealQuickRatio() float64 {
la, lb := len(m.a), len(m.b)
return calculateRatio(min(la, lb), la+lb)
}
// Convert range to the "ed" format
func formatRangeUnified(start, stop int) string {
// Per the diff spec at http://www.unix.org/single_unix_specification/
beginning := start + 1 // lines start numbering with one
length := stop - start
if length == 1 {
return fmt.Sprintf("%d", beginning)
}
if length == 0 {
beginning -= 1 // empty ranges begin at line just before the range
}
return fmt.Sprintf("%d,%d", beginning, length)
}
// Unified diff parameters
type UnifiedDiff struct {
A []string // First sequence lines
FromFile string // First file name
FromDate string // First file time
B []string // Second sequence lines
ToFile string // Second file name
ToDate string // Second file time
Eol string // Headers end of line, defaults to LF
Context int // Number of context lines
}
// Compare two sequences of lines; generate the delta as a unified diff.
//
// Unified diffs are a compact way of showing line changes and a few
// lines of context. The number of context lines is set by 'n' which
// defaults to three.
//
// By default, the diff control lines (those with ---, +++, or @@) are
// created with a trailing newline. This is helpful so that inputs
// created from file.readlines() result in diffs that are suitable for
// file.writelines() since both the inputs and outputs have trailing
// newlines.
//
// For inputs that do not have trailing newlines, set the lineterm
// argument to "" so that the output will be uniformly newline free.
//
// The unidiff format normally has a header for filenames and modification
// times. Any or all of these may be specified using strings for
// 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
// The modification times are normally expressed in the ISO 8601 format.
func WriteUnifiedDiff(writer io.Writer, diff UnifiedDiff) error {
buf := bufio.NewWriter(writer)
defer buf.Flush()
wf := func(format string, args ...interface{}) error {
_, err := buf.WriteString(fmt.Sprintf(format, args...))
return err
}
ws := func(s string) error {
_, err := buf.WriteString(s)
return err
}
if len(diff.Eol) == 0 {
diff.Eol = "\n"
}
started := false
m := NewMatcher(diff.A, diff.B)
for _, g := range m.GetGroupedOpCodes(diff.Context) {
if !started {
started = true
fromDate := ""
if len(diff.FromDate) > 0 {
fromDate = "\t" + diff.FromDate
}
toDate := ""
if len(diff.ToDate) > 0 {
toDate = "\t" + diff.ToDate
}
if diff.FromFile != "" || diff.ToFile != "" {
err := wf("--- %s%s%s", diff.FromFile, fromDate, diff.Eol)
if err != nil {
return err
}
err = wf("+++ %s%s%s", diff.ToFile, toDate, diff.Eol)
if err != nil {
return err
}
}
}
first, last := g[0], g[len(g)-1]
range1 := formatRangeUnified(first.I1, last.I2)
range2 := formatRangeUnified(first.J1, last.J2)
if err := wf("@@ -%s +%s @@%s", range1, range2, diff.Eol); err != nil {
return err
}
for _, c := range g {
i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
if c.Tag == 'e' {
for _, line := range diff.A[i1:i2] {
if err := ws(" " + line); err != nil {
return err
}
}
continue
}
if c.Tag == 'r' || c.Tag == 'd' {
for _, line := range diff.A[i1:i2] {
if err := ws("-" + line); err != nil {
return err
}
}
}
if c.Tag == 'r' || c.Tag == 'i' {
for _, line := range diff.B[j1:j2] {
if err := ws("+" + line); err != nil {
return err
}
}
}
}
}
return nil
}
// Like WriteUnifiedDiff but returns the diff a string.
func GetUnifiedDiffString(diff UnifiedDiff) (string, error) {
w := &bytes.Buffer{}
err := WriteUnifiedDiff(w, diff)
return string(w.Bytes()), err
}
// Split a string on "\n" while preserving them. The output can be used
// as input for UnifiedDiff and ContextDiff structures.
func SplitLines(s string) []string {
lines := strings.SplitAfter(s, "\n")
lines[len(lines)-1] += "\n"
return lines
}

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@ -0,0 +1,266 @@
// Copyright 2022 The Prometheus 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 internal
import (
"bytes"
"fmt"
"math"
"reflect"
"strings"
"testing"
)
func assertAlmostEqual(t *testing.T, a, b float64, places int) {
if math.Abs(a-b) > math.Pow10(-places) {
t.Errorf("%.7f != %.7f", a, b)
}
}
func assertEqual(t *testing.T, a, b interface{}) {
if !reflect.DeepEqual(a, b) {
t.Errorf("%v != %v", a, b)
}
}
func splitChars(s string) []string {
chars := make([]string, 0, len(s))
// Assume ASCII inputs
for i := 0; i != len(s); i++ {
chars = append(chars, string(s[i]))
}
return chars
}
func TestSequenceMatcherRatio(t *testing.T) {
s := NewMatcher(splitChars("abcd"), splitChars("bcde"))
assertEqual(t, s.Ratio(), 0.75)
assertEqual(t, s.QuickRatio(), 0.75)
assertEqual(t, s.RealQuickRatio(), 1.0)
}
func TestGetOptCodes(t *testing.T) {
a := "qabxcd"
b := "abycdf"
s := NewMatcher(splitChars(a), splitChars(b))
w := &bytes.Buffer{}
for _, op := range s.GetOpCodes() {
fmt.Fprintf(w, "%s a[%d:%d], (%s) b[%d:%d] (%s)\n", string(op.Tag),
op.I1, op.I2, a[op.I1:op.I2], op.J1, op.J2, b[op.J1:op.J2])
}
result := string(w.Bytes())
expected := `d a[0:1], (q) b[0:0] ()
e a[1:3], (ab) b[0:2] (ab)
r a[3:4], (x) b[2:3] (y)
e a[4:6], (cd) b[3:5] (cd)
i a[6:6], () b[5:6] (f)
`
if expected != result {
t.Errorf("unexpected op codes: \n%s", result)
}
}
func TestGroupedOpCodes(t *testing.T) {
a := []string{}
for i := 0; i != 39; i++ {
a = append(a, fmt.Sprintf("%02d", i))
}
b := []string{}
b = append(b, a[:8]...)
b = append(b, " i")
b = append(b, a[8:19]...)
b = append(b, " x")
b = append(b, a[20:22]...)
b = append(b, a[27:34]...)
b = append(b, " y")
b = append(b, a[35:]...)
s := NewMatcher(a, b)
w := &bytes.Buffer{}
for _, g := range s.GetGroupedOpCodes(-1) {
fmt.Fprintf(w, "group\n")
for _, op := range g {
fmt.Fprintf(w, " %s, %d, %d, %d, %d\n", string(op.Tag),
op.I1, op.I2, op.J1, op.J2)
}
}
result := string(w.Bytes())
expected := `group
e, 5, 8, 5, 8
i, 8, 8, 8, 9
e, 8, 11, 9, 12
group
e, 16, 19, 17, 20
r, 19, 20, 20, 21
e, 20, 22, 21, 23
d, 22, 27, 23, 23
e, 27, 30, 23, 26
group
e, 31, 34, 27, 30
r, 34, 35, 30, 31
e, 35, 38, 31, 34
`
if expected != result {
t.Errorf("unexpected op codes: \n%s", result)
}
}
func ExampleGetUnifiedDiffCode() {
a := `one
two
three
four
fmt.Printf("%s,%T",a,b)`
b := `zero
one
three
four`
diff := UnifiedDiff{
A: SplitLines(a),
B: SplitLines(b),
FromFile: "Original",
FromDate: "2005-01-26 23:30:50",
ToFile: "Current",
ToDate: "2010-04-02 10:20:52",
Context: 3,
}
result, _ := GetUnifiedDiffString(diff)
fmt.Println(strings.Replace(result, "\t", " ", -1))
// Output:
// --- Original 2005-01-26 23:30:50
// +++ Current 2010-04-02 10:20:52
// @@ -1,5 +1,4 @@
// +zero
// one
// -two
// three
// four
// -fmt.Printf("%s,%T",a,b)
}
func rep(s string, count int) string {
return strings.Repeat(s, count)
}
func TestWithAsciiOneInsert(t *testing.T) {
sm := NewMatcher(splitChars(rep("b", 100)),
splitChars("a"+rep("b", 100)))
assertAlmostEqual(t, sm.Ratio(), 0.995, 3)
assertEqual(t, sm.GetOpCodes(),
[]OpCode{{'i', 0, 0, 0, 1}, {'e', 0, 100, 1, 101}})
assertEqual(t, len(sm.bPopular), 0)
sm = NewMatcher(splitChars(rep("b", 100)),
splitChars(rep("b", 50)+"a"+rep("b", 50)))
assertAlmostEqual(t, sm.Ratio(), 0.995, 3)
assertEqual(t, sm.GetOpCodes(),
[]OpCode{{'e', 0, 50, 0, 50}, {'i', 50, 50, 50, 51}, {'e', 50, 100, 51, 101}})
assertEqual(t, len(sm.bPopular), 0)
}
func TestWithAsciiOnDelete(t *testing.T) {
sm := NewMatcher(splitChars(rep("a", 40)+"c"+rep("b", 40)),
splitChars(rep("a", 40)+rep("b", 40)))
assertAlmostEqual(t, sm.Ratio(), 0.994, 3)
assertEqual(t, sm.GetOpCodes(),
[]OpCode{{'e', 0, 40, 0, 40}, {'d', 40, 41, 40, 40}, {'e', 41, 81, 40, 80}})
}
func TestWithAsciiBJunk(t *testing.T) {
isJunk := func(s string) bool {
return s == " "
}
sm := NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
splitChars(rep("a", 44)+rep("b", 40)), true, isJunk)
assertEqual(t, sm.bJunk, map[string]struct{}{})
sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}})
isJunk = func(s string) bool {
return s == " " || s == "b"
}
sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}, "b": struct{}{}})
}
func TestSFBugsRatioForNullSeqn(t *testing.T) {
sm := NewMatcher(nil, nil)
assertEqual(t, sm.Ratio(), 1.0)
assertEqual(t, sm.QuickRatio(), 1.0)
assertEqual(t, sm.RealQuickRatio(), 1.0)
}
func TestSFBugsComparingEmptyLists(t *testing.T) {
groups := NewMatcher(nil, nil).GetGroupedOpCodes(-1)
assertEqual(t, len(groups), 0)
diff := UnifiedDiff{
FromFile: "Original",
ToFile: "Current",
Context: 3,
}
result, err := GetUnifiedDiffString(diff)
assertEqual(t, err, nil)
assertEqual(t, result, "")
}
func TestOutputFormatRangeFormatUnified(t *testing.T) {
// Per the diff spec at http://www.unix.org/single_unix_specification/
//
// Each <range> field shall be of the form:
// %1d", <beginning line number> if the range contains exactly one line,
// and:
// "%1d,%1d", <beginning line number>, <number of lines> otherwise.
// If a range is empty, its beginning line number shall be the number of
// the line just before the range, or 0 if the empty range starts the file.
fm := formatRangeUnified
assertEqual(t, fm(3, 3), "3,0")
assertEqual(t, fm(3, 4), "4")
assertEqual(t, fm(3, 5), "4,2")
assertEqual(t, fm(3, 6), "4,3")
assertEqual(t, fm(0, 0), "0,0")
}
func TestSplitLines(t *testing.T) {
allTests := []struct {
input string
want []string
}{
{"foo", []string{"foo\n"}},
{"foo\nbar", []string{"foo\n", "bar\n"}},
{"foo\nbar\n", []string{"foo\n", "bar\n", "\n"}},
}
for _, test := range allTests {
assertEqual(t, SplitLines(test.input), test.want)
}
}
func benchmarkSplitLines(b *testing.B, count int) {
str := strings.Repeat("foo\n", count)
b.ResetTimer()
n := 0
for i := 0; i < b.N; i++ {
n += len(SplitLines(str))
}
}
func BenchmarkSplitLines100(b *testing.B) {
benchmarkSplitLines(b, 100)
}
func BenchmarkSplitLines10000(b *testing.B) {
benchmarkSplitLines(b, 10000)
}

View File

@ -41,7 +41,9 @@ import (
"bytes"
"fmt"
"io"
"reflect"
"github.com/davecgh/go-spew/spew"
"github.com/prometheus/common/expfmt"
dto "github.com/prometheus/client_model/go"
@ -211,20 +213,73 @@ func compare(got, want []*dto.MetricFamily) error {
return fmt.Errorf("encoding expected metrics failed: %s", err)
}
}
if wantBuf.String() != gotBuf.String() {
return fmt.Errorf(`
metric output does not match expectation; want:
%s
got:
%s`, wantBuf.String(), gotBuf.String())
if diffErr := diff(wantBuf, gotBuf); diffErr != "" {
return fmt.Errorf(diffErr)
}
return nil
}
// diff returns a diff of both values as long as both are of the same type and
// are a struct, map, slice, array or string. Otherwise it returns an empty string.
func diff(expected interface{}, actual interface{}) string {
if expected == nil || actual == nil {
return ""
}
et, ek := typeAndKind(expected)
at, _ := typeAndKind(actual)
if et != at {
return ""
}
if ek != reflect.Struct && ek != reflect.Map && ek != reflect.Slice && ek != reflect.Array && ek != reflect.String {
return ""
}
var e, a string
c := spew.ConfigState{
Indent: " ",
DisablePointerAddresses: true,
DisableCapacities: true,
SortKeys: true,
}
if et != reflect.TypeOf("") {
e = c.Sdump(expected)
a = c.Sdump(actual)
} else {
e = reflect.ValueOf(expected).String()
a = reflect.ValueOf(actual).String()
}
diff, _ := internal.GetUnifiedDiffString(internal.UnifiedDiff{
A: internal.SplitLines(e),
B: internal.SplitLines(a),
FromFile: "metric output does not match expectation; want",
FromDate: "",
ToFile: "got:",
ToDate: "",
Context: 1,
})
if diff == "" {
return ""
}
return "\n\nDiff:\n" + diff
}
// typeAndKind returns the type and kind of the given interface{}
func typeAndKind(v interface{}) (reflect.Type, reflect.Kind) {
t := reflect.TypeOf(v)
k := t.Kind()
if k == reflect.Ptr {
t = t.Elem()
k = t.Kind()
}
return t, k
}
func filterMetrics(metrics []*dto.MetricFamily, names []string) []*dto.MetricFamily {
var filtered []*dto.MetricFamily
for _, m := range metrics {

View File

@ -284,17 +284,18 @@ func TestMetricNotFound(t *testing.T) {
`
expectedError := `
metric output does not match expectation; want:
# HELP some_other_metric A value that represents a counter.
# TYPE some_other_metric counter
some_other_metric{label1="value1"} 1
Diff:
--- metric output does not match expectation; want
+++ got:
@@ -1,4 +1,4 @@
-(bytes.Buffer) # HELP some_other_metric A value that represents a counter.
-# TYPE some_other_metric counter
-some_other_metric{label1="value1"} 1
+(bytes.Buffer) # HELP some_total A value that represents a counter.
+# TYPE some_total counter
+some_total{label1="value1"} 1
got:
# HELP some_total A value that represents a counter.
# TYPE some_total counter
some_total{label1="value1"} 1
`
err := CollectAndCompare(c, strings.NewReader(metadata+expected))