1 files changed, 287 insertions, 0 deletions
diff --git a/src/cmd/internal/test2json/test2json_test.go b/src/cmd/internal/test2json/test2json_test.go
new file mode 100644
index 0000000..c1aecc8
--- /dev/null
+++ b/src/cmd/internal/test2json/test2json_test.go
@@ -0,0 +1,287 @@
+// 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
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+	"unicode/utf8"
+)
+
+var update = flag.Bool("update", false, "rewrite testdata/*.json files")
+
+func TestGolden(t *testing.T) {
+	files, err := filepath.Glob("testdata/*.test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, file := range files {
+		name := strings.TrimSuffix(filepath.Base(file), ".test")
+		t.Run(name, func(t *testing.T) {
+			orig, err := os.ReadFile(file)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			// Test one line written to c at a time.
+			// Assume that's the most likely to be handled correctly.
+			var buf bytes.Buffer
+			c := NewConverter(&buf, "", 0)
+			in := append([]byte{}, orig...)
+			for _, line := range bytes.SplitAfter(in, []byte("\n")) {
+				writeAndKill(c, line)
+			}
+			c.Close()
+
+			if *update {
+				js := strings.TrimSuffix(file, ".test") + ".json"
+				t.Logf("rewriting %s", js)
+				if err := os.WriteFile(js, buf.Bytes(), 0666); err != nil {
+					t.Fatal(err)
+				}
+				return
+			}
+
+			want, err := os.ReadFile(strings.TrimSuffix(file, ".test") + ".json")
+			if err != nil {
+				t.Fatal(err)
+			}
+			diffJSON(t, buf.Bytes(), want)
+			if t.Failed() {
+				// If the line-at-a-time conversion fails, no point testing boundary conditions.
+				return
+			}
+
+			// Write entire input in bulk.
+			t.Run("bulk", func(t *testing.T) {
+				buf.Reset()
+				c = NewConverter(&buf, "", 0)
+				in = append([]byte{}, orig...)
+				writeAndKill(c, in)
+				c.Close()
+				diffJSON(t, buf.Bytes(), want)
+			})
+
+			// In bulk again with \r\n.
+			t.Run("crlf", func(t *testing.T) {
+				buf.Reset()
+				c = NewConverter(&buf, "", 0)
+				in = bytes.ReplaceAll(orig, []byte("\n"), []byte("\r\n"))
+				writeAndKill(c, in)
+				c.Close()
+				diffJSON(t, bytes.ReplaceAll(buf.Bytes(), []byte(`\r\n`), []byte(`\n`)), want)
+			})
+
+			// Write 2 bytes at a time on even boundaries.
+			t.Run("even2", func(t *testing.T) {
+				buf.Reset()
+				c = NewConverter(&buf, "", 0)
+				in = append([]byte{}, orig...)
+				for i := 0; i < len(in); i += 2 {
+					if i+2 <= len(in) {
+						writeAndKill(c, in[i:i+2])
+					} else {
+						writeAndKill(c, in[i:])
+					}
+				}
+				c.Close()
+				diffJSON(t, buf.Bytes(), want)
+			})
+
+			// Write 2 bytes at a time on odd boundaries.
+			t.Run("odd2", func(t *testing.T) {
+				buf.Reset()
+				c = NewConverter(&buf, "", 0)
+				in = append([]byte{}, orig...)
+				if len(in) > 0 {
+					writeAndKill(c, in[:1])
+				}
+				for i := 1; i < len(in); i += 2 {
+					if i+2 <= len(in) {
+						writeAndKill(c, in[i:i+2])
+					} else {
+						writeAndKill(c, in[i:])
+					}
+				}
+				c.Close()
+				diffJSON(t, buf.Bytes(), want)
+			})
+
+			// Test with very small output buffers, to check that
+			// UTF8 sequences are not broken up.
+			for b := 5; b <= 8; b++ {
+				t.Run(fmt.Sprintf("tiny%d", b), func(t *testing.T) {
+					oldIn := inBuffer
+					oldOut := outBuffer
+					defer func() {
+						inBuffer = oldIn
+						outBuffer = oldOut
+					}()
+					inBuffer = 64
+					outBuffer = b
+					buf.Reset()
+					c = NewConverter(&buf, "", 0)
+					in = append([]byte{}, orig...)
+					writeAndKill(c, in)
+					c.Close()
+					diffJSON(t, buf.Bytes(), want)
+				})
+			}
+		})
+	}
+}
+
+// writeAndKill writes b to w and then fills b with Zs.
+// The filling makes sure that if w is holding onto b for
+// future use, that future use will have obviously wrong data.
+func writeAndKill(w io.Writer, b []byte) {
+	w.Write(b)
+	for i := range b {
+		b[i] = 'Z'
+	}
+}
+
+// diffJSON diffs the stream we have against the stream we want
+// and fails the test with a useful message if they don't match.
+func diffJSON(t *testing.T, have, want []byte) {
+	t.Helper()
+	type event map[string]any
+
+	// Parse into events, one per line.
+	parseEvents := func(b []byte) ([]event, []string) {
+		t.Helper()
+		var events []event
+		var lines []string
+		for _, line := range bytes.SplitAfter(b, []byte("\n")) {
+			if len(line) > 0 {
+				line = bytes.TrimSpace(line)
+				var e event
+				err := json.Unmarshal(line, &e)
+				if err != nil {
+					t.Errorf("unmarshal %s: %v", b, err)
+					continue
+				}
+				events = append(events, e)
+				lines = append(lines, string(line))
+			}
+		}
+		return events, lines
+	}
+	haveEvents, haveLines := parseEvents(have)
+	wantEvents, wantLines := parseEvents(want)
+	if t.Failed() {
+		return
+	}
+
+	// Make sure the events we have match the events we want.
+	// At each step we're matching haveEvents[i] against wantEvents[j].
+	// i and j can move independently due to choices about exactly
+	// how to break up text in "output" events.
+	i := 0
+	j := 0
+
+	// Fail reports a failure at the current i,j and stops the test.
+	// It shows the events around the current positions,
+	// with the current positions marked.
+	fail := func() {
+		var buf bytes.Buffer
+		show := func(i int, lines []string) {
+			for k := -2; k < 5; k++ {
+				marker := ""
+				if k == 0 {
+					marker = "» "
+				}
+				if 0 <= i+k && i+k < len(lines) {
+					fmt.Fprintf(&buf, "\t%s%s\n", marker, lines[i+k])
+				}
+			}
+			if i >= len(lines) {
+				// show marker after end of input
+				fmt.Fprintf(&buf, "\t» \n")
+			}
+		}
+		fmt.Fprintf(&buf, "have:\n")
+		show(i, haveLines)
+		fmt.Fprintf(&buf, "want:\n")
+		show(j, wantLines)
+		t.Fatal(buf.String())
+	}
+
+	var outputTest string             // current "Test" key in "output" events
+	var wantOutput, haveOutput string // collected "Output" of those events
+
+	// getTest returns the "Test" setting, or "" if it is missing.
+	getTest := func(e event) string {
+		s, _ := e["Test"].(string)
+		return s
+	}
+
+	// checkOutput collects output from the haveEvents for the current outputTest
+	// and then checks that the collected output matches the wanted output.
+	checkOutput := func() {
+		for i < len(haveEvents) && haveEvents[i]["Action"] == "output" && getTest(haveEvents[i]) == outputTest {
+			haveOutput += haveEvents[i]["Output"].(string)
+			i++
+		}
+		if haveOutput != wantOutput {
+			t.Errorf("output mismatch for Test=%q:\nhave %q\nwant %q", outputTest, haveOutput, wantOutput)
+			fail()
+		}
+		haveOutput = ""
+		wantOutput = ""
+	}
+
+	// Walk through wantEvents matching against haveEvents.
+	for j = range wantEvents {
+		e := wantEvents[j]
+		if e["Action"] == "output" && getTest(e) == outputTest {
+			wantOutput += e["Output"].(string)
+			continue
+		}
+		checkOutput()
+		if e["Action"] == "output" {
+			outputTest = getTest(e)
+			wantOutput += e["Output"].(string)
+			continue
+		}
+		if i >= len(haveEvents) {
+			t.Errorf("early end of event stream: missing event")
+			fail()
+		}
+		if !reflect.DeepEqual(haveEvents[i], e) {
+			t.Errorf("events out of sync")
+			fail()
+		}
+		i++
+	}
+	checkOutput()
+	if i < len(haveEvents) {
+		t.Errorf("extra events in stream")
+		fail()
+	}
+}
+
+func TestTrimUTF8(t *testing.T) {
+	s := "hello α ☺ 😂 world" // α is 2-byte, ☺ is 3-byte, 😂 is 4-byte
+	b := []byte(s)
+	for i := 0; i < len(s); i++ {
+		j := trimUTF8(b[:i])
+		u := string([]rune(s[:j])) + string([]rune(s[j:]))
+		if u != s {
+			t.Errorf("trimUTF8(%q) = %d (-%d), not at boundary (split: %q %q)", s[:i], j, i-j, s[:j], s[j:])
+		}
+		if utf8.FullRune(b[j:i]) {
+			t.Errorf("trimUTF8(%q) = %d (-%d), too early (missed: %q)", s[:j], j, i-j, s[j:i])
+		}
+	}
+}