unittests: Fixes unit tests for Windows (part 3)

Currently, there are some unit tests that are failing on Windows due to
various reasons:

- paths not properly joined (filepath.Join should be used).
- Proxy Mode IPVS not supported on Windows.
- DeadlineExceeded can occur when trying to read data from an UDP
  socket. This can be used to detect whether the port was closed or not.
- In Windows, with long file name support enabled, file names can have
  up to 32,767 characters. In this case, the error
  windows.ERROR_FILENAME_EXCED_RANGE will be encountered instead.
- files not closed, which means that they cannot be removed / renamed.
- time.Now() is not as precise on Windows, which means that 2
  consecutive calls may return the same timestamp.
- path.Base() will return the same path. filepath.Base() should be used
  instead.
- path.Join() will always join the paths with a / instead of the OS
  specific separator. filepath.Join() should be used instead.

pkg/routes/const_other.go

@@ -0,0 +1,26 @@
+//go:build !windows
+// +build !windows
+
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package routes
+
+import "syscall"
+
+const (
+	fileNameTooLong = syscall.ENAMETOOLONG
+)

pkg/routes/const_windows.go

@@ -0,0 +1,23 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package routes
+
+import "golang.org/x/sys/windows"
+
+const (
+	fileNameTooLong = windows.ERROR_FILENAME_EXCED_RANGE
+)

pkg/routes/logs.go

@@ -20,7 +20,6 @@ import (
 	"net/http"
 	"os"
 	"path"
-	"syscall"
 
 	"github.com/emicklei/go-restful/v3"
 )
@@ -63,7 +62,7 @@ func logFileListHandler(req *restful.Request, resp *restful.Response) {
 func logFileNameIsTooLong(filePath string) bool {
 	_, err := os.Stat(filePath)
 	if err != nil {
-		if e, ok := err.(*os.PathError); ok && e.Err == syscall.ENAMETOOLONG {
+		if e, ok := err.(*os.PathError); ok && e.Err == fileNameTooLong {
 			return true
 		}
 	}

pkg/routes/logs_test.go

@@ -19,11 +19,13 @@ package routes
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 	"testing"
 )
 
 func TestPreCheckLogFileNameLength(t *testing.T) {
-	oversizeFileName := fmt.Sprintf("%0256s", "a")
+	// In windows, with long file name support enabled, file names can have up to 32,767 characters.
+	oversizeFileName := fmt.Sprintf("%032768s", "a")
 	normalFileName := fmt.Sprintf("%0255s", "a")
 
 	// check file with oversize name.
@@ -37,11 +39,19 @@ func TestPreCheckLogFileNameLength(t *testing.T) {
 	}
 
 	// check file with normal name which does exist.
-	_, err := os.Create(normalFileName)
+	dir, err := os.MkdirTemp("", "logs")
+	if err != nil {
+		t.Fatal("failed to create temp dir")
+	}
+	defer os.RemoveAll(dir)
+
+	normalFileName = filepath.Join(dir, normalFileName)
+	f, err := os.Create(normalFileName)
 	if err != nil {
 		t.Error("failed to create test file")
 	}
 	defer os.Remove(normalFileName)
+	defer f.Close()
 	if logFileNameIsTooLong(normalFileName) {
 		t.Error("failed to check normal filename")
 	}