tests: add tests for zkfs utilities (#15002)

Signed-off-by: Eshaan Aggarwal <[email protected]>

go/cmd/zk/internal/zkfs/zkfs.go

@@ -158,6 +158,10 @@ func IsFile(path string) bool {
 
 // ParsePermMode parses the mode string as a perm mask.
 func ParsePermMode(mode string) (mask int32) {
+	if len(mode) < 2 {
+		panic("invalid mode")
+	}
+
 	for _, c := range mode[2:] {
 		mask |= charPermMap[string(c)]
 	}

go/cmd/zk/internal/zkfs/zkfs_test.go

@@ -0,0 +1,83 @@
+/*
+Copyright 2024 The Vitess 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 zkfs
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/z-division/go-zookeeper/zk"
+)
+
+func TestIsFile(t *testing.T) {
+	assert.True(t, IsFile("/zk/somepath"))
+	assert.False(t, IsFile("/nonzk/somepath"))
+	assert.False(t, IsFile("nonzkpath"))
+}
+
+func TestParsePermMode(t *testing.T) {
+	assert.Equal(t, int32(0), ParsePermMode("zk"))
+	assert.Equal(t, int32(zk.PermRead|zk.PermWrite), ParsePermMode("zkrw"))
+	assert.Equal(t, int32(zk.PermRead|zk.PermWrite|zk.PermAdmin), ParsePermMode("zkrwa"))
+	assert.PanicsWithValue(t, "invalid mode", func() {
+		ParsePermMode("")
+	})
+	assert.PanicsWithValue(t, "invalid mode", func() {
+		ParsePermMode("z")
+	})
+}
+
+func TestFormatACL(t *testing.T) {
+	testCases := []struct {
+		name     string
+		acl      zk.ACL
+		expected string
+	}{
+		{
+			name:     "Full Permissions",
+			acl:      zk.ACL{Perms: zk.PermAll},
+			expected: "rwdca",
+		},
+		{
+			name:     "Read and Write Permissions",
+			acl:      zk.ACL{Perms: zk.PermRead | zk.PermWrite},
+			expected: "rw---",
+		},
+		{
+			name:     "No Permissions",
+			acl:      zk.ACL{Perms: 0},
+			expected: "-----",
+		},
+		{
+			name:     "Create and Admin Permissions",
+			acl:      zk.ACL{Perms: zk.PermAdmin | zk.PermCreate},
+			expected: "---ca",
+		},
+		{
+			name:     "Mixed Permissions",
+			acl:      zk.ACL{Perms: zk.PermRead | zk.PermDelete | zk.PermAdmin},
+			expected: "r-d-a",
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			assert.Equal(t, tc.expected, FormatACL(tc.acl))
+		})
+	}
+}