Escape illegal XML characters in junit output (#140)

junit/junit.go

@@ -236,5 +236,27 @@ func formatDuration(d time.Duration) string {
 
 // formatOutput combines the lines from the given output into a single string.
 func formatOutput(output []string) string {
-	return strings.Join(output, "\n")
+	return escapeIllegalChars(strings.Join(output, "\n"))
+}
+
+func escapeIllegalChars(str string) string {
+	return strings.Map(func(r rune) rune {
+		if isInCharacterRange(r) {
+			return r
+		}
+		return '<27>'
+	}, str)
+}
+
+// Decide whether the given rune is in the XML Character Range, per
+// the Char production of https://www.xml.com/axml/testaxml.htm,
+// Section 2.2 Characters.
+// Form: encoding/xml/xml.go
+func isInCharacterRange(r rune) (inrange bool) {
+	return r == 0x09 ||
+		r == 0x0A ||
+		r == 0x0D ||
+		r >= 0x20 && r <= 0xD7FF ||
+		r >= 0xE000 && r <= 0xFFFD ||
+		r >= 0x10000 && r <= 0x10FFFF
 }

junit/junit_test.go

@@ -26,6 +26,11 @@ func TestCreateFromReport(t *testing.T) {
 						Result: gtr.Pass,
 						Output: []string{"ok"},
 					},
+					{
+						Name:   "TestEscapeOutput",
+						Result: gtr.Pass,
+						Output: []string{"\x00\v\f \t\\"},
+					},
 					{
 						Name:   "TestFail",
 						Result: gtr.Fail,
@@ -47,14 +52,14 @@ func TestCreateFromReport(t *testing.T) {
 	}
 
 	want := Testsuites{
-		Tests:    6,
+		Tests:    7,
 		Errors:   3,
 		Failures: 1,
 		Skipped:  1,
 		Suites: []Testsuite{
 			{
 				Name:      "package/name",
-				Tests:     6,
+				Tests:     7,
 				Errors:    3,
 				ID:        0,
 				Failures:  1,
@@ -72,6 +77,12 @@ func TestCreateFromReport(t *testing.T) {
 						Time:      "0.000",
 						SystemOut: &Output{Data: "ok"},
 					},
+					{
+						Name:      "TestEscapeOutput",
+						Classname: "package/name",
+						Time:      "0.000",
+						SystemOut: &Output{Data: `<EFBFBD><EFBFBD><EFBFBD> 	\`},
+					},
 					{
 						Name:      "TestFail",
 						Classname: "package/name",