feat: move MockLogger into a logtest sub-package (#5)

logtest/mocklogger.go

@@ -0,0 +1,51 @@
+// Package logtest provides test helpers for the logging library. It is kept in
+// its own package so that importing the production logging package does not pull
+// in testify (a test-only dependency) — only consumers that import logtest do.
+package logtest
+
+import (
+	"bytes"
+	"log/slog"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func NewMockLogger() *MockLogger {
+	logged := &bytes.Buffer{}
+
+	return &MockLogger{
+		logged: logged,
+		logger: slog.New(slog.NewTextHandler(logged, &slog.HandlerOptions{
+			ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
+				if a.Key == "time" {
+					return slog.Attr{}
+				}
+				return a
+			},
+		})),
+	}
+}
+
+type MockLogger struct {
+	logger *slog.Logger
+	logged *bytes.Buffer
+}
+
+func (m *MockLogger) Logger() *slog.Logger {
+	return m.logger
+}
+
+func (m *MockLogger) Check(t testing.TB, wantLogged []string) {
+	var gotLogged []string
+	if m.logged.String() != "" {
+		gotLogged = strings.Split(m.logged.String(), "\n")
+		gotLogged = gotLogged[:len(gotLogged)-1]
+	}
+	if len(wantLogged) == 0 {
+		assert.Empty(t, gotLogged)
+		return
+	}
+	assert.Equal(t, wantLogged, gotLogged)
+}

logtest/mocklogger_test.go

@@ -0,0 +1,11 @@
+package logtest
+
+import "testing"
+
+func TestMockLogger(t *testing.T) {
+	m := NewMockLogger()
+	m.Logger().Info("hello", "k", "v")
+	m.Check(t, []string{`level=INFO msg=hello k=v`})
+	empty := NewMockLogger()
+	empty.Check(t, nil)
+}