Add test for #924 fix

rust/tests/handles_time0_messages.rs

@@ -0,0 +1,59 @@
+mod common;
+
+// use common::*;
+use std::io::Cursor;
+
+use anyhow::Result;
+
+/// Check that chunks and statistics properly handle messages with log_time = 0
+/// and don't ignore it, using the next time as the minimum.
+#[test]
+fn handles_time0_messages() -> Result<()> {
+    let mut buf = Vec::new();
+    let mut out = mcap::Writer::new(Cursor::new(&mut buf))?;
+
+    // Channels and schemas are automatically assigned ID as they're serialized,
+    // and automatically deduplicated with `Arc` when deserialized.
+    let my_channel = mcap::Channel {
+        topic: String::from("time"),
+        message_encoding: String::from("text/plain"),
+        metadata: Default::default(),
+        schema: None,
+    };
+
+    let channel_id = out.add_channel(&my_channel)?;
+
+    out.write_to_known_channel(
+        &mcap::records::MessageHeader {
+            channel_id,
+            sequence: 1,
+            log_time: 0,
+            publish_time: 0,
+        },
+        b"Time, Dr. Freeman?",
+    )?;
+    out.write_to_known_channel(
+        &mcap::records::MessageHeader {
+            channel_id,
+            sequence: 2,
+            log_time: 42,
+            publish_time: 42,
+        },
+        b"Is it really that time agian?",
+    )?;
+
+    out.finish()?;
+    drop(out);
+
+    let summary = mcap::read::Summary::read(&buf)?.expect("no summary");
+
+    let the_chunk = &summary.chunk_indexes[0];
+    assert_eq!(the_chunk.message_start_time, 0);
+    assert_eq!(the_chunk.message_end_time, 42);
+
+    let stats = &summary.stats.expect("no stats");
+    assert_eq!(stats.message_start_time, 0);
+    assert_eq!(stats.message_end_time, 42);
+
+    Ok(())
+}