1 files changed, 47 insertions, 0 deletions
diff --git a/pkg/rfc822/writer_test.go b/pkg/rfc822/writer_test.go
new file mode 100644
index 0000000..7beae8d
--- /dev/null
+++ b/pkg/rfc822/writer_test.go
@@ -0,0 +1,47 @@
+package rfc822
+
+import (
+	"bytes"
+	"io"
+	"testing"
+)
+
+func TestRfc822Writer_Write(t *testing.T) {
+	tests := []struct {
+		before string
+		after  string
+	}{
+		{"", ""},
+		{"foo", "foo"},
+		{"foo\r", "foo\r\n"},
+		{"foo\n", "foo\r\n"},
+		{"foo\r\n", "foo\r\n"},
+		{"\r", "\r\n"},
+		{"\n", "\r\n"},
+		{"\r\n", "\r\n"},
+		{"foo\rbar", "foo\r\nbar"},
+		{"foo\nbar", "foo\r\nbar"},
+		{"foo\r\nbar", "foo\r\nbar"},
+		{"\r\r", "\r\n\r\n"},
+		{"\n\n", "\r\n\r\n"},
+		{"\r\r\n", "\r\n\r\n"},
+		{"\n\r", "\r\n\r\n"},
+		{"\rbar", "\r\nbar"},
+		{"\nbar", "\r\nbar"},
+		{"\r\nbar", "\r\nbar"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.before, func(t *testing.T) {
+			b := bytes.Buffer{}
+			w := Writer(&b)
+			if _, err := io.WriteString(w, tt.before); err != nil {
+				t.Errorf("Error: %v", err)
+				return
+			}
+			res := b.String()
+			if tt.after != res {
+				t.Errorf("Expected: %q, got: %q", tt.after, res)
+			}
+		})
+	}
+}