internal/log: add unit tests

Signed-off-by: Bobby DeSimone <bobbydesimone@gmail.com>

internal/log/example_test.go

@@ -0,0 +1,34 @@
+// Adapted from https://golang.org/src/log/example_test.go
+// Copyright 2013 The Go Authors. See 3RD-PARTY file for license.
+
+package log_test
+
+import (
+	"bytes"
+	"fmt"
+	stdlog "log"
+	"os"
+
+	"github.com/pomerium/pomerium/internal/log"
+	"github.com/rs/zerolog"
+)
+
+func ExampleLogger() {
+	log.Logger = zerolog.New(os.Stdout).With().Str("level-logging?", "yep!").Logger()
+
+	var (
+		buf    bytes.Buffer
+		logger = stdlog.New(&log.StdLogWrapper{Logger: &log.Logger}, "", 0)
+	)
+
+	logger.Print("Hello logger!")
+	log.SetDebugMode()
+
+	logger.Print("Debug")
+
+	fmt.Print(&buf)
+	// Output:
+	// {"level":"error","level-logging?":"yep!","message":"Hello logger!"}
+	//<nil> ERR Debug level-logging?=yep!
+
+}