upstream-mattermost/server/public/shared/markdown/autolink_test.go

// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package markdown

import (
	"fmt"
	"strings"
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestParseURLAutolink(t *testing.T) {
	testCases := []struct {
		Description string
		Input       string
		Position    int
		Expected    string
	}{
		{
			Description: "no link",
			Input:       "This is an :emoji:",
			Position:    11,
			Expected:    "",
		},
		{
			Description: "no link 2",
			Input:       "These are two things: apple and orange",
			Position:    20,
			Expected:    "",
		},
		{
			Description: "link with http",
			Input:       "http://example.com and some text",
			Position:    4,
			Expected:    "http://example.com",
		},
		{
			Description: "link with https",
			Input:       "https://example.com and some text",
			Position:    5,
			Expected:    "https://example.com",
		},
		{
			Description: "link with ftp",
			Input:       "ftp://example.com and some text",
			Position:    3,
			Expected:    "ftp://example.com",
		},
		{
			Description: "link with a path",
			Input:       "https://example.com/abcd and some text",
			Position:    5,
			Expected:    "https://example.com/abcd",
		},
		{
			Description: "link with parameters",
			Input:       "ftp://example.com/abcd?foo=bar and some text",
			Position:    3,
			Expected:    "ftp://example.com/abcd?foo=bar",
		},
		{
			Description: "link, not at start",
			Input:       "This is https://example.com and some text",
			Position:    13,
			Expected:    "https://example.com",
		},
		{
			Description: "link with a path, not at start",
			Input:       "This is also http://www.example.com/abcd and some text",
			Position:    17,
			Expected:    "http://www.example.com/abcd",
		},
		{
			Description: "link with parameters, not at start",
			Input:       "These are https://www.example.com/abcd?foo=bar and some text",
			Position:    15,
			Expected:    "https://www.example.com/abcd?foo=bar",
		},
		{
			Description: "link with trailing characters",
			Input:       "This is ftp://www.example.com??",
			Position:    11,
			Expected:    "ftp://www.example.com",
		},
		{
			Description: "multiple links",
			Input:       "This is https://example.com/abcd and ftp://www.example.com/1234",
			Position:    13,
			Expected:    "https://example.com/abcd",
		},
		{
			Description: "second of multiple links",
			Input:       "This is https://example.com/abcd and ftp://www.example.com/1234",
			Position:    40,
			Expected:    "ftp://www.example.com/1234",
		},
		{
			Description: "link with brackets",
			Input:       "Go to ftp://www.example.com/my/page_(disambiguation) and some text",
			Position:    9,
			Expected:    "ftp://www.example.com/my/page_(disambiguation)",
		},
		{
			Description: "link in brackets",
			Input:       "(https://www.example.com/foo/bar)",
			Position:    6,
			Expected:    "https://www.example.com/foo/bar",
		},
		{
			Description: "link in underscores",
			Input:       "_http://www.example.com_",
			Position:    5,
			Expected:    "http://www.example.com",
		},
		{
			Description: "link in asterisks",
			Input:       "This is **ftp://example.com**",
			Position:    13,
			Expected:    "ftp://example.com",
		},
		{
			Description: "link in strikethrough",
			Input:       "Those were ~~https://example.com~~",
			Position:    18,
			Expected:    "https://example.com",
		},
		{
			Description: "link in html tags",
			Input:       "<b>We use http://example.com</b>",
			Position:    14,
			Expected:    "http://example.com",
		},
		{
			Description: "bad link protocol",
			Input:       "://///",
			Position:    0,
			Expected:    "",
		},
		{
			Description: "position greater than input length",
			Input:       "there is no colon",
			Position:    1000,
			Expected:    "",
		},
		{
			Description: "no link with angle brackets",
			Input:       "This is an <:emoji:>",
			Position:    15,
			Expected:    "",
		},
		{
			Description: "link with http in angle brackets",
			Input:       "<http://example.com> and some text",
			Position:    5,
			Expected:    "http://example.com",
		},
		{
			Description: "link with https in angle brackets",
			Input:       "<https://example.com> and some text",
			Position:    6,
			Expected:    "https://example.com",
		},
		{
			Description: "link with ftp in angle brackets",
			Input:       "<ftp://example.com> and some text",
			Position:    4,
			Expected:    "ftp://example.com",
		},
		{
			Description: "link with a path in angle brackets",
			Input:       "<https://example.com/abcd> and some text",
			Position:    6,
			Expected:    "https://example.com/abcd",
		},
		{
			Description: "link with parameters in angle brackets",
			Input:       "<ftp://example.com/abcd?foo=bar> and some text",
			Position:    4,
			Expected:    "ftp://example.com/abcd?foo=bar",
		},
		{
			Description: "link, not at start in angle brackets",
			Input:       "This is <https://example.com> and some text",
			Position:    14,
			Expected:    "https://example.com",
		},
		{
			Description: "link with a path, not at start in angle brackets",
			Input:       "This is also <http://www.example.com/abcd> and some text",
			Position:    18,
			Expected:    "http://www.example.com/abcd",
		},
		{
			Description: "link with parameters, not at start in angle brackets",
			Input:       "These are <https://www.example.com/abcd?foo=bar> and some text",
			Position:    16,
			Expected:    "https://www.example.com/abcd?foo=bar",
		},
		{
			Description: "link with trailing characters in angle brackets",
			Input:       "This is <ftp://www.example.com??>",
			Position:    12,
			Expected:    "ftp://www.example.com",
		},
		{
			Description: "multiple links in angle brackets",
			Input:       "This is <https://example.com/abcd> and <ftp://www.example.com/1234>",
			Position:    14,
			Expected:    "https://example.com/abcd",
		},
		{
			Description: "second of multiple links in angle brackets",
			Input:       "This is <https://example.com/abcd> and <ftp://www.example.com/1234>",
			Position:    43,
			Expected:    "ftp://www.example.com/1234",
		},
		{
			Description: "multiple links with first one in angle brackets",
			Input:       "This is <https://example.com/abcd> and ftp://www.example.com/1234",
			Position:    14,
			Expected:    "https://example.com/abcd",
		},
		{
			Description: "second of multiple links with first one in angle brackets",
			Input:       "This is <https://example.com/abcd> and ftp://www.example.com/1234",
			Position:    42,
			Expected:    "ftp://www.example.com/1234",
		},
		{
			Description: "multiple links with second one in angle brackets",
			Input:       "This is https://example.com/abcd and <ftp://www.example.com/1234>",
			Position:    13,
			Expected:    "https://example.com/abcd",
		},
		{
			Description: "second of multiple links with second one in angle brackets",
			Input:       "This is https://example.com/abcd and <ftp://www.example.com/1234>",
			Position:    41,
			Expected:    "ftp://www.example.com/1234",
		},
		{
			Description: "link with brackets wrapped in angle brackets",
			Input:       "Go to <ftp://www.example.com/my/page_(disambiguation)> and some text",
			Position:    10,
			Expected:    "ftp://www.example.com/my/page_(disambiguation)",
		},
		{
			Description: "link with angle brackets in parenthesis",
			Input:       "(<https://www.example.com/foo/bar>)",
			Position:    7,
			Expected:    "https://www.example.com/foo/bar",
		},
		{
			Description: "link with angle brackets in underscores",
			Input:       "_<http://www.example.com>_",
			Position:    6,
			Expected:    "http://www.example.com",
		},
		{
			Description: "link with angle brackets in asterisks",
			Input:       "This is **<ftp://example.com>**",
			Position:    14,
			Expected:    "ftp://example.com",
		},
		{
			Description: "link with angle brackets in strikethrough",
			Input:       "Those were ~~<https://example.com>~~",
			Position:    19,
			Expected:    "https://example.com",
		},
		{
			Description: "link with angle brackets in html tags",
			Input:       "<b>We use <http://example.com></b>",
			Position:    15,
			Expected:    "http://example.com",
		},
	}

	for _, testCase := range testCases {
		t.Run(testCase.Description, func(t *testing.T) {
			rawRange, ok := parseURLAutolink(testCase.Input, testCase.Position)

			if testCase.Expected == "" {
				assert.False(t, ok)
				assert.Equal(t, Range{0, 0}, rawRange)
			} else {
				assert.True(t, ok)
				assert.Equal(t, testCase.Expected, testCase.Input[rawRange.Position:rawRange.End])
			}
		})
	}
}

func TestParseWWWAutolink(t *testing.T) {
	testCases := []struct {
		Description string
		Input       string
		Position    int
		Expected    string
	}{
		{
			Description: "no link",
			Input:       "This is some text",
			Position:    0,
			Expected:    "",
		},
		{
			Description: "link",
			Input:       "www.example.com and some text",
			Position:    0,
			Expected:    "www.example.com",
		},
		{
			Description: "link with a path",
			Input:       "www.example.com/abcd and some text",
			Position:    0,
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "link with parameters",
			Input:       "www.example.com/abcd?foo=bar and some text",
			Position:    0,
			Expected:    "www.example.com/abcd?foo=bar",
		},
		{
			Description: "link, not at start",
			Input:       "This is www.example.com and some text",
			Position:    8,
			Expected:    "www.example.com",
		},
		{
			Description: "link with a path, not at start",
			Input:       "This is also www.example.com/abcd and some text",
			Position:    13,
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "link with parameters, not at start",
			Input:       "These are www.example.com/abcd?foo=bar and some text",
			Position:    10,
			Expected:    "www.example.com/abcd?foo=bar",
		},
		{
			Description: "link with trailing characters",
			Input:       "This is www.example.com??",
			Position:    8,
			Expected:    "www.example.com",
		},
		{
			Description: "link after current position",
			Input:       "This is some text and www.example.com",
			Position:    0,
			Expected:    "",
		},
		{
			Description: "multiple links",
			Input:       "This is www.example.com/abcd and www.example.com/1234",
			Position:    8,
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "multiple links 2",
			Input:       "This is www.example.com/abcd and www.example.com/1234",
			Position:    33,
			Expected:    "www.example.com/1234",
		},
		{
			Description: "link with brackets",
			Input:       "Go to www.example.com/my/page_(disambiguation) and some text",
			Position:    6,
			Expected:    "www.example.com/my/page_(disambiguation)",
		},
		{
			Description: "link following other letters",
			Input:       "aaawww.example.com and some text",
			Position:    3,
			Expected:    "",
		},
		{
			Description: "link in brackets",
			Input:       "(www.example.com)",
			Position:    1,
			Expected:    "www.example.com",
		},
		{
			Description: "link in underscores",
			Input:       "_www.example.com_",
			Position:    1,
			Expected:    "www.example.com",
		},
		{
			Description: "link in asterisks",
			Input:       "This is **www.example.com**",
			Position:    10,
			Expected:    "www.example.com",
		},
		{
			Description: "link in strikethrough",
			Input:       "Those were ~~www.example.com~~",
			Position:    13,
			Expected:    "www.example.com",
		},
		{
			Description: "using www1",
			Input:       "Our backup site is at www1.example.com/foo",
			Position:    22,
			Expected:    "www1.example.com/foo",
		},
		{
			Description: "link in html tags",
			Input:       "<b>We use www2.example.com</b>",
			Position:    10,
			Expected:    "www2.example.com",
		},
		{
			Description: "no link, text with angle brackets",
			Input:       "This is some <> text",
			Position:    0,
			Expected:    "",
		},
		{
			Description: "link with angle brackets",
			Input:       "<www.example.com> and some text",
			Position:    1,
			Expected:    "www.example.com",
		},
		{
			Description: "link with a path in angle brackets",
			Input:       "<www.example.com/abcd> and some text",
			Position:    1,
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "link with parameters in angle brackets",
			Input:       "<www.example.com/abcd?foo=bar> and some text",
			Position:    1,
			Expected:    "www.example.com/abcd?foo=bar",
		},
		{
			Description: "link in angle brackets, not at start",
			Input:       "This is <www.example.com> and some text",
			Position:    len("This is <"),
			Expected:    "www.example.com",
		},
		{
			Description: "link with a path in angle brackets, not at start",
			Input:       "This is also <www.example.com/abcd> and some text",
			Position:    len("This is also <"),
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "link with parameters in angle brackets, not at start",
			Input:       "These are <www.example.com/abcd?foo=bar> and some text",
			Position:    len("These are <"),
			Expected:    "www.example.com/abcd?foo=bar",
		},
		{
			Description: "link with trailing characters in angle brackets",
			Input:       "This is <www.example.com??>",
			Position:    len("This is <"),
			Expected:    "www.example.com",
		},
		{
			Description: "link in angle brackets after current position",
			Input:       "This is some text and <www.example.com>",
			Position:    0,
			Expected:    "",
		},
		{
			Description: "multiple links with angle brackets",
			Input:       "This is <www.example.com/abcd> and <www.example.com/1234>",
			Position:    len("This is <"),
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "multiple links 2 with angle brackets",
			Input:       "This is <www.example.com/abcd> and <www.example.com/1234>",
			Position:    len("This is <www.example.com/abcd> and <"),
			Expected:    "www.example.com/1234",
		},
		{
			Description: "multiple links, last one with angle brackets",
			Input:       "This is www.example.com/abcd and <www.example.com/1234>",
			Position:    len("This is "),
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "multiple links, last one with angle brackets 2",
			Input:       "This is www.example.com/abcd and <www.example.com/1234>",
			Position:    len("This is www.example.com/abcd and <"),
			Expected:    "www.example.com/1234",
		},
		{
			Description: "multiple links, first one with angle brackets",
			Input:       "This is <www.example.com/abcd> and www.example.com/1234",
			Position:    len("This is <"),
			Expected:    "www.example.com/abcd",
		},
		{
			Description: "multiple links, first one with angle brackets 2",
			Input:       "This is <www.example.com/abcd> and www.example.com/1234",
			Position:    len("This is <www.example.com/abcd> and "),
			Expected:    "www.example.com/1234",
		},
		{
			Description: "link with brackets in angle brackets",
			Input:       "Go to <www.example.com/my/page_(disambiguation)> and some text",
			Position:    7,
			Expected:    "www.example.com/my/page_(disambiguation)",
		},
		{
			Description: "link in angle brackets following other letters",
			Input:       "aaa<www.example.com> and some text",
			Position:    4,
			Expected:    "www.example.com",
		},
		{
			Description: "link with angle brackets in parentheses",
			Input:       "(<www.example.com>)",
			Position:    2,
			Expected:    "www.example.com",
		},
		{
			Description: "link with angle brackets in underscores",
			Input:       "_<www.example.com>_",
			Position:    2,
			Expected:    "www.example.com",
		},
		{
			Description: "link with angle brackets in asterisks",
			Input:       "This is **<www.example.com>**",
			Position:    len("This is **<"),
			Expected:    "www.example.com",
		},
		{
			Description: "link with angle brackets in strikethrough",
			Input:       "Those were ~~<www.example.com>~~",
			Position:    len("Those were ~~<"),
			Expected:    "www.example.com",
		},
		{
			Description: "link using www1 in angle brackets",
			Input:       "Our backup site is at <www1.example.com/foo>",
			Position:    len("Our backup site is at <"),
			Expected:    "www1.example.com/foo",
		},
		{
			Description: "link with angle brackets in html tags",
			Input:       "<b>We use <www2.example.com></b>",
			Position:    len("<b>We use <"),
			Expected:    "www2.example.com",
		},
		{
			Description: "link with only opening angle bracket",
			Input:       "<www.example.com and some text",
			Position:    1,
			Expected:    "www.example.com",
		},
		{
			Description: "link with only closing angle bracket",
			Input:       "www.example.com> and some text",
			Position:    0,
			Expected:    "www.example.com",
		},
		{
			Description: "link with only opening bracket",
			Input:       "(www.example.com",
			Position:    1,
			Expected:    "www.example.com",
		},
		{
			Description: "link with only closing bracket",
			Input:       "www.example.com)",
			Position:    0,
			Expected:    "www.example.com",
		},
		{
			Description: "link with underscore at only start",
			Input:       "_www.example.com",
			Position:    1,
			Expected:    "www.example.com",
		},
		{
			Description: "link with underscore at only end",
			Input:       "www.example.com_",
			Position:    0,
			Expected:    "www.example.com",
		},
		{
			Description: "link with asterisks at only start",
			Input:       "This is **www.example.com",
			Position:    10,
			Expected:    "www.example.com",
		},
		{
			Description: "link with asterisks at only end",
			Input:       "This is www.example.com**",
			Position:    8,
			Expected:    "www.example.com",
		},
		{
			Description: "link with tildes at only start",
			Input:       "Those were ~~www.example.com",
			Position:    13,
			Expected:    "www.example.com",
		},
		{
			Description: "link with tildes at only end",
			Input:       "Those were www.example.com~~",
			Position:    11,
			Expected:    "www.example.com",
		},
		{
			Description: "link with only opening html tag",
			Input:       "<b>We use www2.example.com",
			Position:    10,
			Expected:    "www2.example.com",
		},
		{
			Description: "link with only closing html tag",
			Input:       "We use www2.example.com</b>",
			Position:    7,
			Expected:    "www2.example.com",
		},
	}

	for _, testCase := range testCases {
		t.Run(testCase.Description, func(t *testing.T) {
			rawRange, ok := parseWWWAutolink(testCase.Input, testCase.Position)

			if testCase.Expected == "" {
				assert.False(t, ok)
				assert.Equal(t, Range{0, 0}, rawRange)
			} else {
				assert.True(t, ok)
				assert.Equal(t, testCase.Expected, testCase.Input[rawRange.Position:rawRange.End])
			}
		})
	}
}

func TestTrimTrailingCharactersFromLink(t *testing.T) {
	testCases := []struct {
		Input       string
		Start       int
		End         int
		ExpectedEnd int
	}{
		{
			Input:       "http://www.example.com",
			ExpectedEnd: 22,
		},
		{
			Input:       "http://www.example.com/abcd",
			ExpectedEnd: 27,
		},
		{
			Input:       "http://www.example.com/abcd/",
			ExpectedEnd: 28,
		},
		{
			Input:       "http://www.example.com/1234",
			ExpectedEnd: 27,
		},
		{
			Input:       "http://www.example.com/abcd?foo=bar",
			ExpectedEnd: 35,
		},
		{
			Input:       "http://www.example.com/abcd#heading",
			ExpectedEnd: 35,
		},
		{
			Input:       "http://www.example.com.",
			ExpectedEnd: 22,
		},
		{
			Input:       "http://www.example.com,",
			ExpectedEnd: 22,
		},
		{
			Input:       "http://www.example.com?",
			ExpectedEnd: 22,
		},
		{
			Input:       "http://www.example.com)",
			ExpectedEnd: 22,
		},
		{
			Input:       "http://www.example.com",
			ExpectedEnd: 22,
		},
		{
			Input:       "https://en.wikipedia.org/wiki/Dolphin_(disambiguation)",
			ExpectedEnd: 54,
		},
		{
			Input:       "https://en.wikipedia.org/wiki/Dolphin_(disambiguation",
			ExpectedEnd: 53,
		},
		{
			Input:       "https://en.wikipedia.org/wiki/Dolphin_(disambiguation))",
			ExpectedEnd: 54,
		},
		{
			Input:       "https://example.com/" + strings.Repeat(")", 4096),
			ExpectedEnd: len("https://example.com/"),
		},
		{
			Input:       "https://example.com/path_(with_" + strings.Repeat("nested_", 10) + "parens)",
			ExpectedEnd: len("https://example.com/path_(with_" + strings.Repeat("nested_", 10) + "parens)"),
		},
		{
			Input:       "https://example.com/path_((opening-heavy)",
			ExpectedEnd: len("https://example.com/path_((opening-heavy)"),
		},
		{
			Input:       "https://en.wikipedia.org/wiki/Dolphin_(disambiguation)_(disambiguation)",
			ExpectedEnd: 71,
		},
		{
			Input:       "https://en.wikipedia.org/wiki/Dolphin_(disambiguation_(disambiguation))",
			ExpectedEnd: 71,
		},
		{
			Input:       "http://www.example.com&quot;",
			ExpectedEnd: 22,
		},
		{
			Input:       "this is a sentence containing http://www.example.com in it",
			Start:       30,
			End:         52,
			ExpectedEnd: 52,
		},
		{
			Input:       "this is a sentence containing http://www.example.com???",
			Start:       30,
			End:         55,
			ExpectedEnd: 52,
		},
		{
			Input:       "http://google.com/å",
			ExpectedEnd: len("http://google.com/å"),
		},
		{
			Input:       "http://google.com/å...",
			ExpectedEnd: len("http://google.com/å"),
		},
		{
			Input:       "This is http://google.com/å, a link, and http://google.com/å",
			Start:       8,
			End:         len("This is http://google.com/å,"),
			ExpectedEnd: len("This is http://google.com/å"),
		},
		{
			Input:       "This is http://google.com/å, a link, and http://google.com/å",
			Start:       41,
			End:         len("This is http://google.com/å, a link, and http://google.com/å"),
			ExpectedEnd: len("This is http://google.com/å, a link, and http://google.com/å"),
		},
		{
			Input:       "This is http://google.com/å, a link, and http://google.com/å.",
			Start:       41,
			End:         len("This is http://google.com/å, a link, and http://google.com/å."),
			ExpectedEnd: len("This is http://google.com/å, a link, and http://google.com/å"),
		},
		{
			Input:       "http://🍄.ga/ http://x🍄.ga/",
			Start:       0,
			End:         len("http://🍄.ga/"),
			ExpectedEnd: len("http://🍄.ga/"),
		},
		{
			Input:       "http://🍄.ga/ http://x🍄.ga/",
			Start:       len("http://🍄.ga/ "),
			End:         len("http://🍄.ga/ http://x🍄.ga/"),
			ExpectedEnd: len("http://🍄.ga/ http://x🍄.ga/"),
		},
		{
			Input:       "<http://www.example.com>",
			Start:       1,
			ExpectedEnd: 23,
		},
		{
			Input:       "<http://www.example.com&quot;>",
			Start:       1,
			ExpectedEnd: 23,
		},
		{
			Input:       "this is a sentence containing <http://www.example.com> in it",
			Start:       len("this is a sentence containing <"),
			End:         len("this is a sentence containing <http://www.example.com>"),
			ExpectedEnd: 53,
		},
		{
			Input:       "this is a sentence containing <http://www.example.com???>",
			Start:       len("this is a sentence containing <"),
			End:         len("this is a sentence containing <http://www.example.com???>"),
			ExpectedEnd: 53,
		},
	}

	for _, testCase := range testCases {
		t.Run(testCase.Input, func(t *testing.T) {
			if testCase.End == 0 {
				testCase.End = len(testCase.Input) - testCase.Start
			}

			assert.Equal(t, testCase.ExpectedEnd, trimTrailingCharactersFromLink(testCase.Input, testCase.Start, testCase.End))
		})
	}
}

func BenchmarkTrimTrailingCharactersFromLink_UnmatchedClosingParens(b *testing.B) {
	for _, size := range []int{128, 1024, 8192, 65536} {
		b.Run(fmt.Sprintf("closing-%d", size), func(b *testing.B) {
			input := "https://example.com/" + strings.Repeat(")", size)
			expectedEnd := len("https://example.com/")

			b.ReportAllocs()
			for range b.N {
				if end := trimTrailingCharactersFromLink(input, 0, len(input)); end != expectedEnd {
					b.Fatalf("expected end %d, got %d", expectedEnd, end)
				}
			}
		})
	}
}

func TestAutolinking(t *testing.T) {
	// These tests are adapted from https://github.com/mattermost/commonmark.js/test/mattermost.txt.
	// It is missing tests for:
	// 1. Links surrounded by emphasis (emphasis not implemented on the server)
	// 2. IPv6 addresses (not implemented on the server or by GitHub)
	// 3. Custom URL schemes (not implemented)

	for name, tc := range map[string]struct {
		Markdown     string
		ExpectedHTML string
	}{
		"valid-link-1": {
			Markdown:     `http://example.com`,
			ExpectedHTML: `<p><a href="http://example.com">http://example.com</a></p>`,
		},
		"valid-link-2": {
			Markdown:     `https://example.com`,
			ExpectedHTML: `<p><a href="https://example.com">https://example.com</a></p>`,
		},
		"valid-link-3": {
			Markdown:     `ftp://example.com`,
			ExpectedHTML: `<p><a href="ftp://example.com">ftp://example.com</a></p>`,
		},
		// "valid-link-4": {
		// 	Markdown:     `ts3server://example.com?port=9000`,
		// 	ExpectedHTML: `<p><a href="ts3server://example.com?port=9000">ts3server://example.com?port=9000</a></p>`,
		// },
		"valid-link-5": {
			Markdown:     `www.example.com`,
			ExpectedHTML: `<p><a href="http://www.example.com">www.example.com</a></p>`,
		},
		"valid-link-6": {
			Markdown:     `www.example.com/index`,
			ExpectedHTML: `<p><a href="http://www.example.com/index">www.example.com/index</a></p>`,
		},
		"valid-link-7": {
			Markdown:     `www.example.com/index.html`,
			ExpectedHTML: `<p><a href="http://www.example.com/index.html">www.example.com/index.html</a></p>`,
		},
		"valid-link-8": {
			Markdown:     `http://example.com/index/sub`,
			ExpectedHTML: `<p><a href="http://example.com/index/sub">http://example.com/index/sub</a></p>`,
		},
		"valid-link-9": {
			Markdown:     `www1.example.com`,
			ExpectedHTML: `<p><a href="http://www1.example.com">www1.example.com</a></p>`,
		},
		"valid-link-10": {
			Markdown:     `https://en.wikipedia.org/wiki/URLs#Syntax`,
			ExpectedHTML: `<p><a href="https://en.wikipedia.org/wiki/URLs#Syntax">https://en.wikipedia.org/wiki/URLs#Syntax</a></p>`,
		},
		"valid-link-11": {
			Markdown:     `https://groups.google.com/forum/#!msg`,
			ExpectedHTML: `<p><a href="https://groups.google.com/forum/#!msg">https://groups.google.com/forum/#!msg</a></p>`,
		},
		"valid-link-12": {
			Markdown:     `www.example.com/index?params=1`,
			ExpectedHTML: `<p><a href="http://www.example.com/index?params=1">www.example.com/index?params=1</a></p>`,
		},
		"valid-link-13": {
			Markdown:     `www.example.com/index?params=1&other=2`,
			ExpectedHTML: `<p><a href="http://www.example.com/index?params=1&amp;other=2">www.example.com/index?params=1&amp;other=2</a></p>`,
		},
		"valid-link-14": {
			Markdown:     `www.example.com/index?params=1;other=2`,
			ExpectedHTML: `<p><a href="http://www.example.com/index?params=1;other=2">www.example.com/index?params=1;other=2</a></p>`,
		},
		"valid-link-15": {
			Markdown:     `http://www.example.com/_/page`,
			ExpectedHTML: `<p><a href="http://www.example.com/_/page">http://www.example.com/_/page</a></p>`,
		},
		"valid-link-16": {
			Markdown:     `https://en.wikipedia.org/wiki/🐬`,
			ExpectedHTML: `<p><a href="https://en.wikipedia.org/wiki/%F0%9F%90%AC">https://en.wikipedia.org/wiki/🐬</a></p>`,
		},
		"valid-link-17": {
			Markdown:     `http://✪df.ws/1234`,
			ExpectedHTML: `<p><a href="http://%E2%9C%AAdf.ws/1234">http://✪df.ws/1234</a></p>`,
		},
		"valid-link-18": {
			Markdown:     `https://groups.google.com/forum/#!msg`,
			ExpectedHTML: `<p><a href="https://groups.google.com/forum/#!msg">https://groups.google.com/forum/#!msg</a></p>`,
		},
		"valid-link-19": {
			Markdown:     `https://пример.срб/пример-26/`,
			ExpectedHTML: `<p><a href="https://%D0%BF%D1%80%D0%B8%D0%BC%D0%B5%D1%80.%D1%81%D1%80%D0%B1/%D0%BF%D1%80%D0%B8%D0%BC%D0%B5%D1%80-26/">https://пример.срб/пример-26/</a></p>`,
		},
		"valid-link-20": {
			Markdown:     `mailto://test@example.com`,
			ExpectedHTML: `<p><a href="mailto://test@example.com">mailto://test@example.com</a></p>`,
		},
		"valid-link-21": {
			Markdown:     `tel://555-123-4567`,
			ExpectedHTML: `<p><a href="tel://555-123-4567">tel://555-123-4567</a></p>`,
		},

		"ip-address-1": {
			Markdown:     `http://127.0.0.1`,
			ExpectedHTML: `<p><a href="http://127.0.0.1">http://127.0.0.1</a></p>`,
		},
		"ip-address-2": {
			Markdown:     `http://192.168.1.1:4040`,
			ExpectedHTML: `<p><a href="http://192.168.1.1:4040">http://192.168.1.1:4040</a></p>`,
		},
		"ip-address-3": {
			Markdown:     `http://username:password@127.0.0.1`,
			ExpectedHTML: `<p><a href="http://username:password@127.0.0.1">http://username:password@127.0.0.1</a></p>`,
		},
		"ip-address-4": {
			Markdown:     `http://username:password@[2001:0:5ef5:79fb:303a:62d5:3312:ff42]:80`,
			ExpectedHTML: `<p><a href="http://username:password@%5B2001:0:5ef5:79fb:303a:62d5:3312:ff42%5D:80">http://username:password@[2001:0:5ef5:79fb:303a:62d5:3312:ff42]:80</a></p>`,
		},

		"link-with-brackets-1": {
			Markdown:     `https://en.wikipedia.org/wiki/Rendering_(computer_graphics)`,
			ExpectedHTML: `<p><a href="https://en.wikipedia.org/wiki/Rendering_(computer_graphics)">https://en.wikipedia.org/wiki/Rendering_(computer_graphics)</a></p>`,
		},
		"link-with-brackets-2": {
			Markdown:     `http://example.com/more_(than)_one_(parens)`,
			ExpectedHTML: `<p><a href="http://example.com/more_(than)_one_(parens)">http://example.com/more_(than)_one_(parens)</a></p>`,
		},
		"link-with-brackets-3": {
			Markdown:     `http://example.com/(something)?after=parens`,
			ExpectedHTML: `<p><a href="http://example.com/(something)?after=parens">http://example.com/(something)?after=parens</a></p>`,
		},
		"link-with-brackets-4": {
			Markdown:     `http://foo.com/unicode_(✪)_in_parens`,
			ExpectedHTML: `<p><a href="http://foo.com/unicode_(%E2%9C%AA)_in_parens">http://foo.com/unicode_(✪)_in_parens</a></p>`,
		},

		"inside-another-link-1": {
			Markdown:     `[www.example.com](https://example.com)`,
			ExpectedHTML: `<p><a href="https://example.com">www.example.com</a></p>`,
		},
		"inside-another-link-2": {
			Markdown:     `[http://www.example.com](https://example.com)`,
			ExpectedHTML: `<p><a href="https://example.com">http://www.example.com</a></p>`,
		},

		"link-in-sentence-1": {
			Markdown:     `(http://example.com)`,
			ExpectedHTML: `<p>(<a href="http://example.com">http://example.com</a>)</p>`,
		},
		"link-in-sentence-2": {
			Markdown:     `(see http://example.com)`,
			ExpectedHTML: `<p>(see <a href="http://example.com">http://example.com</a>)</p>`,
		},
		"link-in-sentence-3": {
			Markdown:     `(http://example.com watch this)`,
			ExpectedHTML: `<p>(<a href="http://example.com">http://example.com</a> watch this)</p>`,
		},
		"link-in-sentence-4": {
			Markdown:     `This is a sentence with a http://example.com in it.`,
			ExpectedHTML: `<p>This is a sentence with a <a href="http://example.com">http://example.com</a> in it.</p>`,
		},
		"link-in-sentence-5": {
			Markdown:     `This is a sentence with a [link](http://example.com) in it.`,
			ExpectedHTML: `<p>This is a sentence with a <a href="http://example.com">link</a> in it.</p>`,
		},
		"link-in-sentence-6": {
			Markdown:     `This is a sentence with a http://example.com/_/underscore in it.`,
			ExpectedHTML: `<p>This is a sentence with a <a href="http://example.com/_/underscore">http://example.com/_/underscore</a> in it.</p>`,
		},
		"link-in-sentence-7": {
			Markdown:     `This is a sentence with a link (http://example.com) in it.`,
			ExpectedHTML: `<p>This is a sentence with a link (<a href="http://example.com">http://example.com</a>) in it.</p>`,
		},
		"link-in-sentence-8": {
			Markdown:     `This is a sentence with a (https://en.wikipedia.org/wiki/Rendering_(computer_graphics)) in it.`,
			ExpectedHTML: `<p>This is a sentence with a (<a href="https://en.wikipedia.org/wiki/Rendering_(computer_graphics)">https://en.wikipedia.org/wiki/Rendering_(computer_graphics)</a>) in it.</p>`,
		},
		"link-in-sentence-9": {
			Markdown:     `This is a sentence with a http://192.168.1.1:4040 in it.`,
			ExpectedHTML: `<p>This is a sentence with a <a href="http://192.168.1.1:4040">http://192.168.1.1:4040</a> in it.</p>`,
		},
		"link-in-sentence-10": {
			Markdown:     `This is a link to http://example.com.`,
			ExpectedHTML: `<p>This is a link to <a href="http://example.com">http://example.com</a>.</p>`,
		},
		"link-in-sentence-11": {
			Markdown:     `This is a link to http://example.com*`,
			ExpectedHTML: `<p>This is a link to <a href="http://example.com">http://example.com</a>*</p>`,
		},
		"link-in-sentence-12": {
			Markdown:     `This is a link to http://example.com_`,
			ExpectedHTML: `<p>This is a link to <a href="http://example.com">http://example.com</a>_</p>`,
		},
		"link-in-sentence-13": {
			Markdown:     `This is a link containing http://example.com/something?with,commas,in,url, but not at the end`,
			ExpectedHTML: `<p>This is a link containing <a href="http://example.com/something?with,commas,in,url">http://example.com/something?with,commas,in,url</a>, but not at the end</p>`,
		},
		"link-in-sentence-14": {
			Markdown:     `This is a question about a link http://example.com?`,
			ExpectedHTML: `<p>This is a question about a link <a href="http://example.com">http://example.com</a>?</p>`,
		},

		"plt-7250-link-with-trailing-periods-1": {
			Markdown:     `http://example.com.`,
			ExpectedHTML: `<p><a href="http://example.com">http://example.com</a>.</p>`,
		},
		"plt-7250-link-with-trailing-periods-2": {
			Markdown:     `http://example.com...`,
			ExpectedHTML: `<p><a href="http://example.com">http://example.com</a>...</p>`,
		},
		"plt-7250-link-with-trailing-periods-3": {
			Markdown:     `http://example.com/foo.`,
			ExpectedHTML: `<p><a href="http://example.com/foo">http://example.com/foo</a>.</p>`,
		},
		"plt-7250-link-with-trailing-periods-4": {
			Markdown:     `http://example.com/foo...`,
			ExpectedHTML: `<p><a href="http://example.com/foo">http://example.com/foo</a>...</p>`,
		},
		"plt-7250-link-with-trailing-periods-5": {
			Markdown:     `http://example.com/foo.bar`,
			ExpectedHTML: `<p><a href="http://example.com/foo.bar">http://example.com/foo.bar</a></p>`,
		},
		"plt-7250-link-with-trailing-periods-6": {
			Markdown:     `http://example.com/foo...bar`,
			ExpectedHTML: `<p><a href="http://example.com/foo...bar">http://example.com/foo...bar</a></p>`,
		},

		"rn-319-www-link-as-part-of-word-1": {
			Markdown:     `testwww.example.com`,
			ExpectedHTML: `<p>testwww.example.com</p>`,
		},

		"mm-10180-link-containing-period-followed-by-non-letter-1": {
			Markdown:     `https://example.com/123.+Pagetitle`,
			ExpectedHTML: `<p><a href="https://example.com/123.+Pagetitle">https://example.com/123.+Pagetitle</a></p>`,
		},
		"mm-10180-link-containing-period-followed-by-non-letter-2": {
			Markdown:     `https://example.com/123.?Pagetitle`,
			ExpectedHTML: `<p><a href="https://example.com/123.?Pagetitle">https://example.com/123.?Pagetitle</a></p>`,
		},
		"mm-10180-link-containing-period-followed-by-non-letter-3": {
			Markdown:     `https://example.com/123.-Pagetitle`,
			ExpectedHTML: `<p><a href="https://example.com/123.-Pagetitle">https://example.com/123.-Pagetitle</a></p>`,
		},
		"mm-10180-link-containing-period-followed-by-non-letter-4": {
			Markdown:     `https://example.com/123._Pagetitle`,
			ExpectedHTML: `<p><a href="https://example.com/123._Pagetitle">https://example.com/123._Pagetitle</a></p>`,
		},
		"mm-10180-link-containing-period-followed-by-non-letter-5": {
			Markdown:     `https://example.com/123.+`,
			ExpectedHTML: `<p><a href="https://example.com/123.+">https://example.com/123.+</a></p>`,
		},
		"mm-10180-link-containing-period-followed-by-non-letter-6": {
			Markdown:     `https://example.com/123.?`,
			ExpectedHTML: `<p><a href="https://example.com/123">https://example.com/123</a>.?</p>`,
		},
		"mm-10180-link-containing-period-followed-by-non-letter-7": {
			Markdown:     `https://example.com/123.-`,
			ExpectedHTML: `<p><a href="https://example.com/123.-">https://example.com/123.-</a></p>`,
		},
		"mm-10180-link-containing-period-followed-by-non-letter-8": {
			Markdown:     `https://example.com/123._`,
			ExpectedHTML: `<p><a href="https://example.com/123">https://example.com/123</a>._</p>`,
		},
	} {
		t.Run(name, func(t *testing.T) {
			assert.Equal(t, tc.ExpectedHTML, RenderHTML(tc.Markdown))
		})
	}
}

func Test_isAllowedBeforeWWWLink(t *testing.T) {
	type args struct {
		c byte
	}
	tests := []struct {
		name string
		args args
		want bool
	}{
		{
			name: "empty space",
			args: args{
				c: byte(' '),
			},
			want: false,
		},
		{
			name: "asterisk",
			args: args{
				c: byte('*'),
			},
			want: true,
		},
		{
			name: "underscore",
			args: args{
				c: byte('_'),
			},
			want: true,
		},
		{
			name: "open parenthesis",
			args: args{
				c: byte('('),
			},
			want: true,
		},
		{
			name: "close parenthesis",
			args: args{
				c: byte(')'),
			},
			want: true,
		},
		{
			name: "tilde",
			args: args{
				c: byte('~'),
			},
			want: true,
		},
		{
			name: "open angle bracket",
			args: args{
				c: byte('<'),
			},
			want: true,
		},
		{
			name: "close angle bracket",
			args: args{
				c: byte('>'),
			},
			want: true,
		},
		{
			name: "alphabet",
			args: args{
				c: byte('c'),
			},
			want: false,
		},
		{
			name: "number",
			args: args{
				c: byte('4'),
			},
			want: false,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			assert.Equalf(t, tt.want, isAllowedBeforeWWWLink(tt.args.c), "isAllowedBeforeWWWLink(%v)", tt.args.c)
		})
	}
}