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// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package test2json implements conversion of test binary output to JSON.
// It is used by cmd/test2json and cmd/go.
//
// See the cmd/test2json documentation for details of the JSON encoding.
package test2json
import (
"bytes"
"encoding/json"
"fmt"
"io"
"strconv"
"strings"
"time"
"unicode"
"unicode/utf8"
)
// Mode controls details of the conversion.
type Mode int
const (
Timestamp Mode = 1 << iota // include Time in events
)
// event is the JSON struct we emit.
type event struct {
Time *time.Time `json:",omitempty"`
Action string
Package string `json:",omitempty"`
Test string `json:",omitempty"`
Elapsed *float64 `json:",omitempty"`
Output *textBytes `json:",omitempty"`
}
// textBytes is a hack to get JSON to emit a []byte as a string
// without actually copying it to a string.
// It implements encoding.TextMarshaler, which returns its text form as a []byte,
// and then json encodes that text form as a string (which was our goal).
type textBytes []byte
func (b textBytes) MarshalText() ([]byte, error) { return b, nil }
// A converter holds the state of a test-to-JSON conversion.
// It implements io.WriteCloser; the caller writes test output in,
// and the converter writes JSON output to w.
type converter struct {
w io.Writer // JSON output stream
pkg string // package to name in events
mode Mode // mode bits
start time.Time // time converter started
testName string // name of current test, for output attribution
report []*event // pending test result reports (nested for subtests)
result string // overall test result if seen
input lineBuffer // input buffer
output lineBuffer // output buffer
}
// inBuffer and outBuffer are the input and output buffer sizes.
// They're variables so that they can be reduced during testing.
//
// The input buffer needs to be able to hold any single test
// directive line we want to recognize, like:
//
// <many spaces> --- PASS: very/nested/s/u/b/t/e/s/t
//
// If anyone reports a test directive line > 4k not working, it will
// be defensible to suggest they restructure their test or test names.
//
// The output buffer must be >= utf8.UTFMax, so that it can
// accumulate any single UTF8 sequence. Lines that fit entirely
// within the output buffer are emitted in single output events.
// Otherwise they are split into multiple events.
// The output buffer size therefore limits the size of the encoding
// of a single JSON output event. 1k seems like a reasonable balance
// between wanting to avoid splitting an output line and not wanting to
// generate enormous output events.
var (
inBuffer = 4096
outBuffer = 1024
)
// NewConverter returns a "test to json" converter.
// Writes on the returned writer are written as JSON to w,
// with minimal delay.
//
// The writes to w are whole JSON events ending in \n,
// so that it is safe to run multiple tests writing to multiple converters
// writing to a single underlying output stream w.
// As long as the underlying output w can handle concurrent writes
// from multiple goroutines, the result will be a JSON stream
// describing the relative ordering of execution in all the concurrent tests.
//
// The mode flag adjusts the behavior of the converter.
// Passing ModeTime includes event timestamps and elapsed times.
//
// The pkg string, if present, specifies the import path to
// report in the JSON stream.
func NewConverter(w io.Writer, pkg string, mode Mode) io.WriteCloser {
c := new(converter)
*c = converter{
w: w,
pkg: pkg,
mode: mode,
start: time.Now(),
input: lineBuffer{
b: make([]byte, 0, inBuffer),
line: c.handleInputLine,
part: c.output.write,
},
output: lineBuffer{
b: make([]byte, 0, outBuffer),
line: c.writeOutputEvent,
part: c.writeOutputEvent,
},
}
return c
}
// Write writes the test input to the converter.
func (c *converter) Write(b []byte) (int, error) {
c.input.write(b)
return len(b), nil
}
var (
bigPass = []byte("PASS\n")
bigFail = []byte("FAIL\n")
updates = [][]byte{
[]byte("=== RUN "),
[]byte("=== PAUSE "),
[]byte("=== CONT "),
}
reports = [][]byte{
[]byte("--- PASS: "),
[]byte("--- FAIL: "),
[]byte("--- SKIP: "),
[]byte("--- BENCH: "),
}
fourSpace = []byte(" ")
skipLinePrefix = []byte("? \t")
skipLineSuffix = []byte("\t[no test files]\n")
)
// handleInputLine handles a single whole test output line.
// It must write the line to c.output but may choose to do so
// before or after emitting other events.
func (c *converter) handleInputLine(line []byte) {
// Final PASS or FAIL.
if bytes.Equal(line, bigPass) || bytes.Equal(line, bigFail) {
c.flushReport(0)
c.output.write(line)
if bytes.Equal(line, bigPass) {
c.result = "pass"
} else {
c.result = "fail"
}
return
}
// Special case for entirely skipped test binary: "? \tpkgname\t[no test files]\n" is only line.
// Report it as plain output but remember to say skip in the final summary.
if bytes.HasPrefix(line, skipLinePrefix) && bytes.HasSuffix(line, skipLineSuffix) && len(c.report) == 0 {
c.result = "skip"
}
// "=== RUN "
// "=== PAUSE "
// "=== CONT "
actionColon := false
origLine := line
ok := false
indent := 0
for _, magic := range updates {
if bytes.HasPrefix(line, magic) {
ok = true
break
}
}
if !ok {
// "--- PASS: "
// "--- FAIL: "
// "--- SKIP: "
// "--- BENCH: "
// but possibly indented.
for bytes.HasPrefix(line, fourSpace) {
line = line[4:]
indent++
}
for _, magic := range reports {
if bytes.HasPrefix(line, magic) {
actionColon = true
ok = true
break
}
}
}
if !ok {
// Not a special test output line.
c.output.write(origLine)
return
}
// Parse out action and test name.
i := 0
if actionColon {
i = bytes.IndexByte(line, ':') + 1
}
if i == 0 {
i = len(updates[0])
}
action := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(string(line[4:i])), ":"))
name := strings.TrimSpace(string(line[i:]))
e := &event{Action: action}
if line[0] == '-' { // PASS or FAIL report
// Parse out elapsed time.
if i := strings.Index(name, " ("); i >= 0 {
if strings.HasSuffix(name, "s)") {
t, err := strconv.ParseFloat(name[i+2:len(name)-2], 64)
if err == nil {
if c.mode&Timestamp != 0 {
e.Elapsed = &t
}
}
}
name = name[:i]
}
if len(c.report) < indent {
// Nested deeper than expected.
// Treat this line as plain output.
c.output.write(origLine)
return
}
// Flush reports at this indentation level or deeper.
c.flushReport(indent)
e.Test = name
c.testName = name
c.report = append(c.report, e)
c.output.write(origLine)
return
}
// === update.
// Finish any pending PASS/FAIL reports.
c.flushReport(0)
c.testName = name
if action == "pause" {
// For a pause, we want to write the pause notification before
// delivering the pause event, just so it doesn't look like the test
// is generating output immediately after being paused.
c.output.write(origLine)
}
c.writeEvent(e)
if action != "pause" {
c.output.write(origLine)
}
return
}
// flushReport flushes all pending PASS/FAIL reports at levels >= depth.
func (c *converter) flushReport(depth int) {
c.testName = ""
for len(c.report) > depth {
e := c.report[len(c.report)-1]
c.report = c.report[:len(c.report)-1]
c.writeEvent(e)
}
}
// Close marks the end of the go test output.
// It flushes any pending input and then output (only partial lines at this point)
// and then emits the final overall package-level pass/fail event.
func (c *converter) Close() error {
c.input.flush()
c.output.flush()
e := &event{Action: "pass"}
if c.result != "" {
e.Action = c.result
}
if c.mode&Timestamp != 0 {
dt := time.Since(c.start).Round(1 * time.Millisecond).Seconds()
e.Elapsed = &dt
}
c.writeEvent(e)
return nil
}
// writeOutputEvent writes a single output event with the given bytes.
func (c *converter) writeOutputEvent(out []byte) {
c.writeEvent(&event{
Action: "output",
Output: (*textBytes)(&out),
})
}
// writeEvent writes a single event.
// It adds the package, time (if requested), and test name (if needed).
func (c *converter) writeEvent(e *event) {
e.Package = c.pkg
if c.mode&Timestamp != 0 {
t := time.Now()
e.Time = &t
}
if e.Test == "" {
e.Test = c.testName
}
js, err := json.Marshal(e)
if err != nil {
// Should not happen - event is valid for json.Marshal.
c.w.Write([]byte(fmt.Sprintf("testjson internal error: %v\n", err)))
return
}
js = append(js, '\n')
c.w.Write(js)
}
// A lineBuffer is an I/O buffer that reacts to writes by invoking
// input-processing callbacks on whole lines or (for long lines that
// have been split) line fragments.
//
// It should be initialized with b set to a buffer of length 0 but non-zero capacity,
// and line and part set to the desired input processors.
// The lineBuffer will call line(x) for any whole line x (including the final newline)
// that fits entirely in cap(b). It will handle input lines longer than cap(b) by
// calling part(x) for sections of the line. The line will be split at UTF8 boundaries,
// and the final call to part for a long line includes the final newline.
type lineBuffer struct {
b []byte // buffer
mid bool // whether we're in the middle of a long line
line func([]byte) // line callback
part func([]byte) // partial line callback
}
// write writes b to the buffer.
func (l *lineBuffer) write(b []byte) {
for len(b) > 0 {
// Copy what we can into b.
m := copy(l.b[len(l.b):cap(l.b)], b)
l.b = l.b[:len(l.b)+m]
b = b[m:]
// Process lines in b.
i := 0
for i < len(l.b) {
j := bytes.IndexByte(l.b[i:], '\n')
if j < 0 {
if !l.mid {
if j := bytes.IndexByte(l.b[i:], '\t'); j >= 0 {
if isBenchmarkName(bytes.TrimRight(l.b[i:i+j], " ")) {
l.part(l.b[i : i+j+1])
l.mid = true
i += j + 1
}
}
}
break
}
e := i + j + 1
if l.mid {
// Found the end of a partial line.
l.part(l.b[i:e])
l.mid = false
} else {
// Found a whole line.
l.line(l.b[i:e])
}
i = e
}
// Whatever's left in l.b is a line fragment.
if i == 0 && len(l.b) == cap(l.b) {
// The whole buffer is a fragment.
// Emit it as the beginning (or continuation) of a partial line.
t := trimUTF8(l.b)
l.part(l.b[:t])
l.b = l.b[:copy(l.b, l.b[t:])]
l.mid = true
}
// There's room for more input.
// Slide it down in hope of completing the line.
if i > 0 {
l.b = l.b[:copy(l.b, l.b[i:])]
}
}
}
// flush flushes the line buffer.
func (l *lineBuffer) flush() {
if len(l.b) > 0 {
// Must be a line without a \n, so a partial line.
l.part(l.b)
l.b = l.b[:0]
}
}
var benchmark = []byte("Benchmark")
// isBenchmarkName reports whether b is a valid benchmark name
// that might appear as the first field in a benchmark result line.
func isBenchmarkName(b []byte) bool {
if !bytes.HasPrefix(b, benchmark) {
return false
}
if len(b) == len(benchmark) { // just "Benchmark"
return true
}
r, _ := utf8.DecodeRune(b[len(benchmark):])
return !unicode.IsLower(r)
}
// trimUTF8 returns a length t as close to len(b) as possible such that b[:t]
// does not end in the middle of a possibly-valid UTF-8 sequence.
//
// If a large text buffer must be split before position i at the latest,
// splitting at position trimUTF(b[:i]) avoids splitting a UTF-8 sequence.
func trimUTF8(b []byte) int {
// Scan backward to find non-continuation byte.
for i := 1; i < utf8.UTFMax && i <= len(b); i++ {
if c := b[len(b)-i]; c&0xc0 != 0x80 {
switch {
case c&0xe0 == 0xc0:
if i < 2 {
return len(b) - i
}
case c&0xf0 == 0xe0:
if i < 3 {
return len(b) - i
}
case c&0xf8 == 0xf0:
if i < 4 {
return len(b) - i
}
}
break
}
}
return len(b)
}