rewrite utility funcs tests

Signed-off-by: Mohammed Al Sahaf <msaa1990@gmail.com>

modules/caddyhttp/rewrite/rewrite_utils_test.go

@@ -0,0 +1,194 @@
+// Copyright 2015 Matthew Holt and The Caddy 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 rewrite
+
+import (
+	"testing"
+)
+
+func TestReverse(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "simple string",
+			input:    "hello",
+			expected: "olleh",
+		},
+		{
+			name:     "empty string",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "single character",
+			input:    "a",
+			expected: "a",
+		},
+		{
+			name:     "two characters",
+			input:    "ab",
+			expected: "ba",
+		},
+		{
+			name:     "palindrome",
+			input:    "racecar",
+			expected: "racecar",
+		},
+		{
+			name:     "with spaces",
+			input:    "hello world",
+			expected: "dlrow olleh",
+		},
+		{
+			name:     "with numbers",
+			input:    "abc123",
+			expected: "321cba",
+		},
+		{
+			name:     "unicode characters",
+			input:    "hello世界",
+			expected: "界世olleh",
+		},
+		{
+			name:     "emoji",
+			input:    "🎉🎊🎈",
+			expected: "🎈🎊🎉",
+		},
+		{
+			name:     "mixed unicode and ascii",
+			input:    "café☕",
+			expected: "☕éfac",
+		},
+		{
+			name:     "special characters",
+			input:    "a!b@c#d$",
+			expected: "$d#c@b!a",
+		},
+		{
+			name:     "path-like string",
+			input:    "/path/to/file",
+			expected: "elif/ot/htap/",
+		},
+		{
+			name:     "url-like string",
+			input:    "https://example.com",
+			expected: "moc.elpmaxe//:sptth",
+		},
+		{
+			name:     "long string",
+			input:    "The quick brown fox jumps over the lazy dog",
+			expected: "god yzal eht revo spmuj xof nworb kciuq ehT",
+		},
+		{
+			name:     "newlines",
+			input:    "line1\nline2\nline3",
+			expected: "3enil\n2enil\n1enil",
+		},
+		{
+			name:     "tabs",
+			input:    "a\tb\tc",
+			expected: "c\tb\ta",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := reverse(tt.input)
+			if result != tt.expected {
+				t.Errorf("reverse(%q) = %q; want %q", tt.input, result, tt.expected)
+			}
+
+			// Test that reversing twice gives the original string
+			if tt.input != "" {
+				doubleReverse := reverse(reverse(tt.input))
+				if doubleReverse != tt.input {
+					t.Errorf("reverse(reverse(%q)) = %q; want %q", tt.input, doubleReverse, tt.input)
+				}
+			}
+		})
+	}
+}
+
+func TestReverse_LengthPreservation(t *testing.T) {
+	// Test that reverse preserves string length
+	testStrings := []string{
+		"",
+		"a",
+		"ab",
+		"abc",
+		"hello world",
+		"🎉🎊🎈",
+		"café☕",
+		"The quick brown fox jumps over the lazy dog",
+	}
+
+	for _, s := range testStrings {
+		reversed := reverse(s)
+		if len([]rune(s)) != len([]rune(reversed)) {
+			t.Errorf("reverse(%q) changed length: original %d, reversed %d", s, len([]rune(s)), len([]rune(reversed)))
+		}
+	}
+}
+
+// BenchmarkReverse benchmarks the reverse function
+func BenchmarkReverse(b *testing.B) {
+	testCases := []struct {
+		name  string
+		input string
+	}{
+		{"empty", ""},
+		{"short", "hello"},
+		{"medium", "The quick brown fox jumps over the lazy dog"},
+		{"long", "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."},
+		{"unicode", "hello世界🎉"},
+	}
+
+	for _, tc := range testCases {
+		b.Run(tc.name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				reverse(tc.input)
+			}
+		})
+	}
+}
+
+func TestReverse_EdgeCases(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+	}{
+		{"null byte", "\x00"},
+		{"multiple null bytes", "\x00\x00\x00"},
+		{"control characters", "\t\n\r"},
+		{"high unicode", "𝕳𝖊𝖑𝖑𝖔"},
+		{"zero-width characters", "a\u200Bb\u200Cc"},
+		{"combining characters", "é"}, // e + combining acute
+		{"rtl text", "مرحبا"},
+		{"mixed rtl/ltr", "Hello مرحبا World"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := reverse(tt.input)
+			// Just ensure it doesn't panic and returns something
+			if result == "" && tt.input != "" {
+				t.Errorf("reverse(%q) returned empty string", tt.input)
+			}
+		})
+	}
+}