Added String() methods for AddrHeader and Header (incl. tests)

header.go

@@ -152,3 +152,13 @@ func (i Importance) String() string {
 		return ""
 	}
 }
+
+// String returns the header string based on the given Header
+func (h Header) String() string {
+	return string(h)
+}
+
+// String returns the address header string based on the given AddrHeader
+func (a AddrHeader) String() string {
+	return string(a)
+}

header_test.go

@@ -37,3 +37,65 @@ func TestImportance_StringFuncs(t *testing.T) {
 		})
 	}
 }
+
+// TestAddrHeader_String tests the string method of the AddrHeader object
+func TestAddrHeader_String(t *testing.T) {
+	tests := []struct {
+		name string
+		ah   AddrHeader
+		want string
+	}{
+		{"Address header: From", HeaderFrom, "From"},
+		{"Address header: To", HeaderTo, "To"},
+		{"Address header: Cc", HeaderCc, "Cc"},
+		{"Address header: Bcc", HeaderBcc, "Bcc"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.ah.String() != tt.want {
+				t.Errorf("wrong string for AddrHeader returned. Expected: %s, got: %s",
+					tt.want, tt.ah.String())
+			}
+		})
+	}
+}
+
+// TestHeader_String tests the string method of the Header object
+func TestHeader_String(t *testing.T) {
+	tests := []struct {
+		name string
+		h    Header
+		want string
+	}{
+		{"Header: Content-Disposition", HeaderContentDisposition, "Content-Disposition"},
+		{"Header: Content-ID", HeaderContentID, "Content-ID"},
+		{"Header: Content-Language", HeaderContentLang, "Content-Language"},
+		{"Header: Content-Location", HeaderContentLocation, "Content-Location"},
+		{"Header: Content-Transfer-Encoding", HeaderContentTransferEnc, "Content-Transfer-Encoding"},
+		{"Header: Content-Type", HeaderContentType, "Content-Type"},
+		{"Header: Date", HeaderDate, "Date"},
+		{"Header: Importance", HeaderImportance, "Importance"},
+		{"Header: In-Reply-To", HeaderInReplyTo, "In-Reply-To"},
+		{"Header: List-Unsubscribe", HeaderListUnsubscribe, "List-Unsubscribe"},
+		{"Header: List-Unsubscribe-Post", HeaderListUnsubscribePost, "List-Unsubscribe-Post"},
+		{"Header: Message-ID", HeaderMessageID, "Message-ID"},
+		{"Header: MIME-Version", HeaderMIMEVersion, "MIME-Version"},
+		{"Header: Organization", HeaderOrganization, "Organization"},
+		{"Header: Precedence", HeaderPrecedence, "Precedence"},
+		{"Header: Priority", HeaderPriority, "Priority"},
+		{"Header: Reply-To", HeaderReplyTo, "Reply-To"},
+		{"Header: Subject", HeaderSubject, "Subject"},
+		{"Header: User-Agent", HeaderUserAgent, "User-Agent"},
+		{"Header: X-Mailer", HeaderXMailer, "X-Mailer"},
+		{"Header: X-MSMail-Priority", HeaderXMSMailPriority, "X-MSMail-Priority"},
+		{"Header: X-Priority", HeaderXPriority, "X-Priority"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.h.String() != tt.want {
+				t.Errorf("wrong string for Header returned. Expected: %s, got: %s",
+					tt.want, tt.h.String())
+			}
+		})
+	}
+}