mox!

store/msgreader_test.go

@@ -0,0 +1,77 @@
+package store
+
+import (
+	"io"
+	"os"
+	"testing"
+)
+
+func TestMsgreader(t *testing.T) {
+	_, err := io.Copy(io.Discard, &MsgReader{prefix: []byte("hello"), path: "bogus.txt", size: int64(len("hello"))})
+	if err == nil || !os.IsNotExist(err) {
+		t.Fatalf("expected error for non-existing file, got %s", err)
+	}
+
+	if buf, err := io.ReadAll(&MsgReader{prefix: []byte("hello"), path: "/dev/null", size: int64(len("hello"))}); err != nil {
+		t.Fatalf("readall: %s", err)
+	} else if string(buf) != "hello" {
+		t.Fatalf("got %q, expected %q", buf, "hello")
+	}
+
+	if err := os.WriteFile("msgreader_test.txt", []byte(" world"), 0660); err != nil {
+		t.Fatalf("writing msgreader_test.txt: %s", err)
+	}
+	defer os.Remove("msgreader_test.txt")
+	mr := &MsgReader{prefix: []byte("hello"), path: "msgreader_test.txt", size: int64(len("hello world"))}
+	if buf, err := io.ReadAll(mr); err != nil {
+		t.Fatalf("readall: %s", err)
+	} else if string(buf) != "hello world" {
+		t.Fatalf("got %q, expected %q", buf, "hello world")
+	}
+
+	mr.Reset()
+	buf := make([]byte, 32)
+	if n, err := mr.ReadAt(buf, 1); err != nil && err != io.EOF {
+		t.Fatalf("readat: n %d, s %q, err %s", n, buf[:n], err)
+	} else if n != len("ello world") || string(buf[:n]) != "ello world" {
+		t.Fatalf("readat: got %d bytes (%q), expected %d (%q)", n, buf, int64(len("ello world")), "ello world")
+	}
+
+	// Read with 1 byte at a time to exercise the offset/buffer-length calculations.
+	buf = make([]byte, 1)
+	var result []byte
+	mr = &MsgReader{prefix: []byte("hello"), path: "msgreader_test.txt", size: int64(len("hello world"))}
+	for {
+		n, err := mr.Read(buf)
+		if n > 0 {
+			result = append(result, buf...)
+		}
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("read: %s", err)
+		}
+	}
+	if string(result) != "hello world" {
+		t.Fatalf("got %q, want %q", result, "hello world")
+	}
+
+	if err := mr.Close(); err != nil {
+		t.Fatalf("close: %v", err)
+	}
+
+	f, err := os.Open("msgreader_test.txt")
+	if err != nil {
+		t.Fatalf("open: %v", err)
+	}
+	mr = FileMsgReader([]byte("hello"), f)
+
+	if mr.Size() != int64(len("hello world")) {
+		t.Fatalf("size, got %d, expect %d", mr.Size(), len("hello world"))
+	}
+
+	if err := mr.Close(); err != nil {
+		t.Fatalf("close: %v", err)
+	}
+}