From a4e5c91cb823526765574c6d18ea6b13f1cb7dab Mon Sep 17 00:00:00 2001
From: kennytm <kennytm@gmail.com>
Date: Sat, 4 Nov 2017 02:44:54 +0800
Subject: [PATCH] libtest: Force a newline every 100 dots when testing in quiet
 mode.

Rationale:

We use --quiet mode when testing a PR in the CI. Also, we use `stamp` to
prefix every line with a timestamp. Previously, when testing in --quiet
mode, we will only print a dot for each test without any line breaks.
Combined with `stamp`, this means we'd need to wait for all tests to
complete before writing the output. On Travis CI, if we don't print
anything within 30 minutes, the job will be forcefully canceled. This
makes it very easy to spuriously-timeout when testing non-default images
like arm-android using the CI. This commit tries to workaround the issue
by printing a new line every 100 dots, forcing `stamp` to emit something
to reset Travis's countdown.
---
 src/libtest/lib.rs | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/libtest/lib.rs b/src/libtest/lib.rs
index e8a1242c8145..76abcb83edc5 100644
--- a/src/libtest/lib.rs
+++ b/src/libtest/lib.rs
@@ -71,6 +71,7 @@ use std::thread;
 use std::time::{Instant, Duration};
 
 const TEST_WARN_TIMEOUT_S: u64 = 60;
+const QUIET_MODE_MAX_COLUMN: usize = 100; // insert a '\n' after 100 tests in quiet mode
 
 // to be used by rustc to compile tests in libtest
 pub mod test {
@@ -614,7 +615,14 @@ impl<T: Write> ConsoleTestState<T> {
     pub fn write_short_result(&mut self, verbose: &str, quiet: &str, color: term::color::Color)
                               -> io::Result<()> {
         if self.quiet {
-            self.write_pretty(quiet, color)
+            self.write_pretty(quiet, color)?;
+            if self.current_test_count() % QUIET_MODE_MAX_COLUMN == QUIET_MODE_MAX_COLUMN - 1 {
+                // we insert a new line every 100 dots in order to flush the
+                // screen when dealing with line-buffered output (e.g. piping to
+                // `stamp` in the rust CI).
+                self.write_plain("\n")?;
+            }
+            Ok(())
         } else {
             self.write_pretty(verbose, color)?;
             self.write_plain("\n")
@@ -771,9 +779,12 @@ impl<T: Write> ConsoleTestState<T> {
         Ok(())
     }
 
+    fn current_test_count(&self) -> usize {
+        self.passed + self.failed + self.ignored + self.measured + self.allowed_fail
+    }
+
     pub fn write_run_finish(&mut self) -> io::Result<bool> {
-        assert!(self.passed + self.failed + self.ignored + self.measured +
-                    self.allowed_fail == self.total);
+        assert!(self.current_test_count() == self.total);
 
         if self.options.display_output {
             self.write_outputs()?;