parser/gotest: Create go test -json parser

pkg/parser/gotest/json.go

@@ -0,0 +1,77 @@
+package gotest
+
+import (
+	"bufio"
+	"encoding/json"
+	"io"
+	"time"
+
+	"github.com/jstemmer/go-junit-report/v2/pkg/gtr"
+)
+
+// New returns a new Go test json output parser.
+func NewJSON(options ...Option) *JSONParser {
+	return &JSONParser{gp: New(options...)}
+}
+
+// Parser is a Go test json output Parser.
+type JSONParser struct {
+	gp *Parser
+}
+
+// Parse parses Go test json output from the given io.Reader r and returns
+// gtr.Report.
+func (p *JSONParser) Parse(r io.Reader) (gtr.Report, error) {
+	return p.gp.Parse(newJSONReader(r))
+}
+
+// Events returns the events created by the parser.
+func (p *JSONParser) Events() []Event {
+	return p.gp.Events()
+}
+
+type jsonEvent struct {
+	Time    time.Time
+	Action  string
+	Package string
+	Test    string
+	Elapsed float64 // seconds
+	Output  string
+}
+
+type jsonReader struct {
+	r   *bufio.Reader
+	buf []byte
+}
+
+func newJSONReader(reader io.Reader) *jsonReader {
+	return &jsonReader{r: bufio.NewReader(reader)}
+}
+
+func (j *jsonReader) Read(p []byte) (int, error) {
+	var err error
+	for len(j.buf) == 0 {
+		j.buf, err = j.readNextLine()
+		if err != nil {
+			return 0, err
+		}
+	}
+	n := copy(p, j.buf)
+	j.buf = j.buf[n:]
+	return n, nil
+}
+
+func (j jsonReader) readNextLine() ([]byte, error) {
+	line, err := j.r.ReadBytes('\n')
+	if err != nil {
+		return nil, err
+	}
+	if len(line) == 0 || line[0] != '{' {
+		return line, nil
+	}
+	var event jsonEvent
+	if err := json.Unmarshal(line, &event); err != nil {
+		return nil, err
+	}
+	return []byte(event.Output), nil
+}

pkg/parser/gotest/json_test.go

@@ -0,0 +1,63 @@
+package gotest
+
+import (
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+var input = `some other output
+{"Time":"2019-10-09T00:00:00.708139047+00:00","Action":"output","Package":"package/name/ok","Test":"TestOK"}
+{"Time":"2019-10-09T00:00:00.708139047+00:00","Action":"output","Package":"package/name/ok","Test":"TestOK","Output":"=== RUN   TestOK\n"}
+`
+
+func TestJSONReaderReadAll(t *testing.T) {
+	r := newJSONReader(strings.NewReader(input))
+	got, err := io.ReadAll(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := `some other output
+=== RUN   TestOK
+`
+
+	if diff := cmp.Diff(string(got), want); diff != "" {
+		t.Errorf("unexpected result from jsonReader, diff (-got, +want):\n%s\n", diff)
+	}
+}
+
+func TestJSONReaderReadSmallBuffer(t *testing.T) {
+	expected := [][]byte{
+		[]byte("some"),
+		[]byte(" oth"),
+		[]byte("er o"),
+		[]byte("utpu"),
+		[]byte("t\n"),
+		[]byte("=== "),
+		[]byte("RUN "),
+		[]byte("  Te"),
+		[]byte("stOK"),
+		[]byte("\n"),
+	}
+
+	r := newJSONReader(strings.NewReader(input))
+	buf := make([]byte, 4)
+	for _, want := range expected {
+		n, err := r.Read(buf)
+		if err != nil {
+			t.Fatalf("Read error: %v", err)
+		}
+
+		if diff := cmp.Diff(string(buf[:n]), string(want)); diff != "" {
+			t.Fatalf("unexpected result from jsonReader, diff (-got, +want):\n%s\n", diff)
+		}
+	}
+
+	_, err := r.Read(buf)
+	if err != io.EOF {
+		t.Fatalf("unexpected result from jsonReader: got %v, want %v", err, io.EOF)
+	}
+}