Add a TimeUntilNextTry to reading list

ios/chrome/browser/reading_list/reading_list_entry_unittest.cc

Index: ios/chrome/browser/reading_list/reading_list_entry_unittest.cc
diff --git a/ios/chrome/browser/reading_list/reading_list_entry_unittest.cc b/ios/chrome/browser/reading_list/reading_list_entry_unittest.cc
index 215c3fdd32df3c9a0d0ff76facae81c995ee8fd4..9b5d9384225df6621b425e9c11d28d37de894cee 100644
--- a/ios/chrome/browser/reading_list/reading_list_entry_unittest.cc
+++ b/ios/chrome/browser/reading_list/reading_list_entry_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "ios/chrome/browser/reading_list/reading_list_entry.h"
 
+#include "base/test/simple_test_tick_clock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(ReadingListEntry, CompareIgnoreTitle) {
@@ -50,3 +51,47 @@ TEST(ReadingListEntry, DistilledState) {
   e.SetDistilledURL(distilled_url);
   EXPECT_EQ(ReadingListEntry::PROCESSED, e.DistilledState());
 }
+
+// Tests that the the time until next try increase exponentially when the state
+// changes from non-error to error.
+TEST(ReadingListEntry, TimeUntilNextTry) {
+  base::SimpleTestTickClock clock;
+  ReadingListEntry e(GURL("http://example.com"), "bar", &clock);
+
+  ASSERT_EQ(0, e.TimeUntilNextTry().InSeconds());
+
+  e.SetDistilledState(ReadingListEntry::ERROR);
+  EXPECT_EQ(1, e.TimeUntilNextTry().InSeconds());
+  e.SetDistilledState(ReadingListEntry::WILL_RETRY);
+  EXPECT_EQ(1, e.TimeUntilNextTry().InSeconds());
+
+  e.SetDistilledState(ReadingListEntry::PROCESSING);
+  EXPECT_EQ(1, e.TimeUntilNextTry().InSeconds());
+
+  e.SetDistilledState(ReadingListEntry::WILL_RETRY);
+  EXPECT_EQ(2, e.TimeUntilNextTry().InSeconds());
+  e.SetDistilledState(ReadingListEntry::ERROR);
+  EXPECT_EQ(2, e.TimeUntilNextTry().InSeconds());
+
+  e.SetDistilledState(ReadingListEntry::PROCESSING);
+  EXPECT_EQ(2, e.TimeUntilNextTry().InSeconds());
+
+  e.SetDistilledState(ReadingListEntry::WILL_RETRY);
+  EXPECT_EQ(4, e.TimeUntilNextTry().InSeconds());
+}
+
+// Tests that if the time until next try is in the past, 0 is returned.
+TEST(ReadingListEntry, TimeUntilNextTryInThePast) {
+  // Setup.
+  base::SimpleTestTickClock clock;
+  ReadingListEntry e(GURL("http://example.com"), "bar", &clock);
+
+  e.SetDistilledState(ReadingListEntry::ERROR);
+  ASSERT_EQ(1, e.TimeUntilNextTry().InSeconds());
+
+  // Action.
+  clock.Advance(base::TimeDelta::FromSeconds(2));
+
+  // Test.
+  EXPECT_EQ(0, e.TimeUntilNextTry().InMilliseconds());
+}