fix ephemeral file tests

Signed-off-by: Yuchen Liang <[email protected]>

pageserver/src/tenant/ephemeral_file.rs

@@ -346,16 +346,22 @@ mod tests {
         }
 
         assert!(file.len() as usize == write_nbytes);
-        for i in 0..write_nbytes {
+        let align = virtual_file::get_io_buffer_alignment();
+
+        for i in (0..write_nbytes).step_by(align) {
             assert_eq!(value_offsets[i], i.into_u64());
-            let buf = IoBufferMut::with_capacity(1);
+            let buf = IoBufferMut::with_capacity(align);
             let (buf_slice, nread) = file
                 .read_exact_at_eof_ok(i.into_u64(), buf.slice_full(), &ctx)
                 .await
                 .unwrap();
             let buf = buf_slice.into_inner();
-            assert_eq!(nread, 1);
-            assert_eq!(&buf, &content[i..i + 1]);
+            if i + align > write_nbytes {
+                assert_eq!(nread, i % align);
+            } else {
+                assert_eq!(nread, align);
+            }
+            assert_eq!(&buf, &content[i..(i + align).min(write_nbytes)]);
         }
 
         let file_contents =
@@ -436,6 +442,7 @@ mod tests {
         file.write_raw(&content, &ctx).await.unwrap();
 
         let test_read = |start: usize, len: usize| {
+            println!("cap={cap}, start={start}, len={len}");
             let file = &file;
             let ctx = &ctx;
             let content = &content;
@@ -453,16 +460,17 @@ mod tests {
             }
         };
 
+        let align = virtual_file::get_io_buffer_alignment();
         // completely within the file range
-        assert!(20 < cap, "test assumption");
-        test_read(10, 10).await;
+        assert!(align * 2 < cap, "test assumption");
+        test_read(align, align).await;
         // border onto edge of file
-        test_read(cap - 10, 10).await;
+        test_read(cap - align, align).await;
         // read across file and buffer
-        test_read(cap - 10, 20).await;
+        test_read(cap - align, align * 2).await;
         // stay from start of buffer
-        test_read(cap, 10).await;
+        test_read(cap, align).await;
         // completely within buffer
-        test_read(cap + 10, 10).await;
+        test_read(cap + align, align).await;
     }
 }