From 805b145a06325e8150a23356715aaab2fc1a4b15 Mon Sep 17 00:00:00 2001
From: Lukasz Mierzwa <lukasz@cloudflare.com>
Date: Fri, 6 Dec 2024 16:32:16 +0000
Subject: [PATCH] Add tests for log handler

---
 internal/log/handler_test.go | 106 +++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 internal/log/handler_test.go

diff --git a/internal/log/handler_test.go b/internal/log/handler_test.go
new file mode 100644
index 00000000..5d792b4e
--- /dev/null
+++ b/internal/log/handler_test.go
@@ -0,0 +1,106 @@
+package log
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"log/slog"
+	"strconv"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestHandler(t *testing.T) {
+	type testCaseT struct {
+		run      func(l *slog.Logger)
+		expected string
+		noColor  bool
+	}
+
+	testCases := []testCaseT{
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				l.Debug("foo", slog.Int("count", 5))
+			},
+			expected: "level=DEBUG msg=foo count=5\n",
+		},
+		{
+			noColor: false,
+			run: func(l *slog.Logger) {
+				l.Debug("foo", slog.Int("count", 5))
+			},
+			expected: "level=DEBUG msg=foo count=5\n",
+		},
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				l.Debug("foo", slog.Int("count", 5))
+				l.Info("bar", slog.String("string", "a b c"), slog.Any("list", []int{1, 2, 3}))
+			},
+			expected: "level=DEBUG msg=foo count=5\nlevel=INFO msg=bar string=\"a b c\" list=[1,2,3]\n",
+		},
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				l.Warn("bar", slog.Any("strings", []string{"a", "b", "c + d"}))
+			},
+			expected: "level=WARN msg=bar strings=[\"a\",\"b\",\"c + d\"]\n",
+		},
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				l.Error("bar", slog.Any("err", errors.New("error")))
+			},
+			expected: "level=ERROR msg=bar err=error\n",
+		},
+		{
+			noColor: false,
+			run: func(l *slog.Logger) {
+				l.Error("bar", slog.Any("err", errors.New("error")))
+			},
+			expected: "level=ERROR msg=bar err=error\n",
+		},
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				l.Error("bar", slog.Any("err", nil))
+			},
+			expected: "level=ERROR msg=bar err=null\n",
+		},
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				type Foo struct {
+					N json.Number
+				}
+				x := Foo{json.Number(`invalid`)}
+				l.Error("bar", slog.Any("err", x))
+			},
+			expected: "level=ERROR msg=bar err={invalid}\n",
+		},
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				l.With(slog.String("with", "true")).Error("bar")
+			},
+			expected: "level=ERROR msg=bar\n",
+		},
+		{
+			noColor: true,
+			run: func(l *slog.Logger) {
+				l.Info("bar", slog.Group("group", slog.String("with", "true")))
+			},
+			expected: "level=INFO msg=bar group=[{\"Key\":\"with\",\"Value\":{}}]\n",
+		},
+	}
+
+	for i, tc := range testCases {
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
+			dst := bytes.NewBufferString("")
+			tc.run(slog.New(newHandler(dst, slog.LevelDebug.Level(), tc.noColor)))
+			require.Equal(t, tc.expected, dst.String())
+		})
+	}
+}