Unescape HTML in a skype message to prevent element issues.

This remains secure as matrix clients SHOULD only render specific HTML tags, so there is no expectation that server side messages are secure by default.

Add basic tests for formatter.parseSkype for the new escaping bug. This could be expanded in the future to include all the other functions.

Closes #1

formatting.go

@@ -18,6 +18,7 @@ var italicRegex = regexp.MustCompile("([\\s>~*]|^)_(.+?)_([^a-zA-Z\\d]|$)")
 var boldRegex = regexp.MustCompile("([\\s>_~]|^)\\*(.+?)\\*([^a-zA-Z\\d]|$)")
 var strikethroughRegex = regexp.MustCompile("([\\s>_*]|^)~(.+?)~([^a-zA-Z\\d]|$)")
 var codeBlockRegex = regexp.MustCompile("```(?:.|\n)+?```")
+
 //var mentionRegex = regexp.MustCompile("@[0-9]+")
 //var mentionRegex = regexp.MustCompile("@(.*)")
 var mentionRegex = regexp.MustCompile("<at[^>]+\\bid=\"([^\"]+)\"(.*?)</at>*")
@@ -125,6 +126,7 @@ func (formatter *Formatter) ParseSkype(content *event.MessageEventContent) {
 	}
 	if output != content.Body {
 		output = strings.Replace(output, "\n", "<br/>", -1)
+		content.Body = html.UnescapeString(content.Body) // skype messages arrive escaped which causes element rendering issues #1
 
 		// parse @user message
 		r := regexp.MustCompile(`<at[^>]+\bid="([^"]+)"(.*?)</at>*`)

formatting_test.go

@@ -0,0 +1,96 @@
+package main
+
+import (
+	"github.com/kelaresg/matrix-skype/database"
+	"github.com/kelaresg/matrix-skype/types"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/format"
+	"reflect"
+	"regexp"
+	"sync"
+	"testing"
+)
+
+func TestFormatter_ParseSkype(t *testing.T) {
+	type fields struct {
+		bridge           *Bridge
+		matrixHTMLParser *format.HTMLParser
+		waReplString     map[*regexp.Regexp]string
+		waReplFunc       map[*regexp.Regexp]func(string) string
+		waReplFuncText   map[*regexp.Regexp]func(string) string
+	}
+	type args struct {
+		content *event.MessageEventContent
+	}
+	type expect struct {
+		content *event.MessageEventContent
+	}
+	testUser := &User{
+		User: &database.User{
+			MXID: "mxtestid",
+		},
+	}
+	testBridge := &Bridge{
+		usersLock:  *new(sync.Mutex),
+		usersByJID: map[types.SkypeID]*User{"test": testUser},
+	}
+	testFormatter := &Formatter{
+		bridge: testBridge,
+	}
+	tests := []struct {
+		name   string
+		args   args
+		expect expect
+	}{
+		{
+			"simple message",
+			args{
+				&event.MessageEventContent{
+					Body: "This is a very simple message.",
+				},
+			},
+			expect{
+				&event.MessageEventContent{
+					Body: "This is a very simple message.",
+				},
+			},
+		},
+		{
+			"simple punctuation test",
+			args{
+				&event.MessageEventContent{
+					Body: "It's the inclusion of "simple" punctuation that causes most of the problems.",
+				},
+			},
+			expect{
+				&event.MessageEventContent{
+					Body:   "It's the inclusion of \"simple\" punctuation that causes most of the problems.",
+					Format: event.FormatHTML,
+				},
+			},
+		},
+		{
+			"full punctuation test",
+			args{
+				&event.MessageEventContent{
+					Body:   "&<>"&#39", // use a few different encodings
+					Format: event.FormatHTML,
+				},
+			},
+			expect{
+				&event.MessageEventContent{
+					Body:   "&<>\"'",
+					Format: event.FormatHTML,
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			testFormatter.ParseSkype(tt.args.content)
+			if !reflect.DeepEqual(tt.args.content, tt.expect.content) {
+				t.Errorf("content = %v, wanted %v", tt.args.content, tt.expect.content)
+			}
+		})
+	}
+}