type.go: Bugfix for newlines interpreted as binary. Add tests.

Fixes #55

v3/common/type.go

@@ -156,11 +156,11 @@ type SignedRational struct {
 }
 
 func isPrintableText(s string) bool {
-
-	// TODO(dustin): Add text
-
 	for _, c := range s {
-		if unicode.IsPrint(rune(c)) == false {
+		// unicode.IsPrint() returns false for newline characters.
+		if c == 0x0d || c == 0x0a {
+			continue
+		} else if unicode.IsPrint(rune(c)) == false {
 			return false
 		}
 	}

v3/common/type_test.go

@@ -411,3 +411,27 @@ func TestTranslateStringToType__InvalidType(t *testing.T) {
 //     log.Panicf("from-string encoding for type not supported; this shouldn't happen: [%s]", tagType.String())
 //     return nil, nil
 // }
+
+func TestIsPrintableText_letters(t *testing.T) {
+	if isPrintableText("abc") != true {
+		t.Fatalf("Printable text interpreted as nonprintable.")
+	}
+}
+
+func TestIsPrintableText_space(t *testing.T) {
+	if isPrintableText(" ") != true {
+		t.Fatalf("Printable text interpreted as nonprintable.")
+	}
+}
+
+func TestIsPrintableText_newlines(t *testing.T) {
+	if isPrintableText("\r\n") != true {
+		t.Fatalf("Printable text interpreted as nonprintable.")
+	}
+}
+
+func TestIsPrintableText_punctuationAndSymbols(t *testing.T) {
+	if isPrintableText(",:-/$©") != true {
+		t.Fatalf("Printable text interpreted as nonprintable.")
+	}
+}