chore: add tests for clog.ErrGroup

Author: cmoog

internal/x/xsync/doc.go

@@ -0,0 +1,2 @@
+// Package xsync provides utilities for concurrency.
+package xsync

internal/x/xsync/syncwriter.go

@@ -0,0 +1,24 @@
+package xsync
+
+import (
+	"io"
+	"sync"
+)
+
+// Writer synchronizes concurrent writes to an underlying writer.
+func Writer(w io.Writer) io.Writer {
+	return &writer{
+		w: w,
+	}
+}
+
+type writer struct {
+	mu sync.Mutex
+	w  io.Writer
+}
+
+func (sw *writer) Write(b []byte) (int, error) {
+	sw.mu.Lock()
+	defer sw.mu.Unlock()
+	return sw.w.Write(b)
+}

pkg/clog/errgroup_test.go

@@ -0,0 +1,43 @@
+package clog
+
+import (
+	"bytes"
+	"errors"
+	"strings"
+	"testing"
+
+	"cdr.dev/slog/sloggers/slogtest/assert"
+
+	"cdr.dev/coder-cli/internal/x/xsync"
+)
+
+func TestErrGroup(t *testing.T) {
+	t.Run("success", func(t *testing.T) {
+		egroup := LoggedErrGroup()
+
+		var buf bytes.Buffer
+		SetOutput(xsync.Writer(&buf))
+
+		egroup.Go(func() error { return nil })
+		egroup.Go(func() error { return nil })
+		egroup.Go(func() error { return nil })
+
+		err := egroup.Wait()
+		assert.Success(t, "error group wait", err)
+		assert.Equal(t, "empty log buffer", "", buf.String())
+	})
+	t.Run("failure_count", func(t *testing.T) {
+		egroup := LoggedErrGroup()
+
+		var buf bytes.Buffer
+		SetOutput(xsync.Writer(&buf))
+
+		egroup.Go(func() error { return errors.New("whoops") })
+		egroup.Go(func() error { return Error("rich error", "second line") })
+
+		err := egroup.Wait()
+		assert.ErrorContains(t, "error group wait", err, "2 failures emitted")
+		assert.True(t, "log buf contains", strings.Contains(buf.String(), "fatal: whoops\n\n"))
+		assert.True(t, "log buf contains", strings.Contains(buf.String(), "error: rich error\n  | second line\n\n"))
+	})
+}