diff --git a/Justfile b/Justfile
index 352903d..953a57b 100644
--- a/Justfile
+++ b/Justfile
@@ -23,4 +23,5 @@ ci-test:
 	source <(cargo llvm-cov show-env --export-prefix)
 	cargo llvm-cov clean --workspace
 	cargo nextest run --all-features --profile ci
+	ONE_BYTE_READ=1 cargo nextest run --all-features --release --profile ci
 	cargo llvm-cov report --lcov --output-path coverage.lcov
diff --git a/rc-zip-sync/tests/integration_tests.rs b/rc-zip-sync/tests/integration_tests.rs
index 3df5500..f07225b 100644
--- a/rc-zip-sync/tests/integration_tests.rs
+++ b/rc-zip-sync/tests/integration_tests.rs
@@ -3,9 +3,12 @@ use rc_zip::{
     error::Error,
     parse::Archive,
 };
-use rc_zip_sync::{ArchiveHandle, HasCursor, ReadZip, ReadZipStreaming};
+use rc_zip_sync::{ArchiveHandle, HasCursor, ReadZip, ReadZipStreaming, ReadZipWithSize};
 
-use std::{fs::File, io::Read};
+use std::{
+    fs::File,
+    io::{self, Read},
+};
 
 fn check_case<F: HasCursor>(test: &Case, archive: Result<ArchiveHandle<'_, F>, Error>) {
     corpus::check_case(test, archive.as_ref().map(|ar| -> &Archive { ar }));
@@ -49,8 +52,15 @@ fn real_world_files() {
 
         let guarded_path = case.absolute_path();
         let file = File::open(&guarded_path.path).unwrap();
-        let archive = file.read_zip().map_err(Error::from);
-        check_case(&case, archive);
+        if let Ok("1") = std::env::var("ONE_BYTE_READ").as_deref() {
+            let size = file.metadata().unwrap().len();
+            let file = OneByteReadWrapper(file);
+            let archive = file.read_zip_with_size(size).map_err(Error::from);
+            check_case(&case, archive);
+        } else {
+            let archive = file.read_zip().map_err(Error::from);
+            check_case(&case, archive);
+        };
         drop(guarded_path)
     }
 }
@@ -78,3 +88,27 @@ fn streaming() {
         drop(guarded_path)
     }
 }
+
+// This helps find bug in state machines!
+
+struct OneByteReadWrapper<R>(R);
+
+impl<R> io::Read for OneByteReadWrapper<R>
+where
+    R: io::Read,
+{
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        self.0.read(&mut buf[..1])
+    }
+}
+
+impl<R> HasCursor for OneByteReadWrapper<R>
+where
+    R: HasCursor,
+{
+    type Cursor<'a> = OneByteReadWrapper<R::Cursor<'a>> where R: 'a;
+
+    fn cursor_at(&self, offset: u64) -> Self::Cursor<'_> {
+        OneByteReadWrapper(self.0.cursor_at(offset))
+    }
+}