[sql] Tests for updates to mmap state.

sql/connection_unittest.cc

Index: sql/connection_unittest.cc
diff --git a/sql/connection_unittest.cc b/sql/connection_unittest.cc
index a08456e36a86eeb62330761ed2dad06dc80aa949..09324772ed326ce50648d6a429c61fbd237e6d8f 100644
--- a/sql/connection_unittest.cc
+++ b/sql/connection_unittest.cc
@@ -1546,6 +1546,12 @@ TEST_F(SQLConnectionTest, GetAppropriateMmapSize) {
   ASSERT_TRUE(MetaTable::GetMmapStatus(&db(), &mmap_status));
   ASSERT_EQ(MetaTable::kMmapSuccess, mmap_status);
 
+  // Preload with partial progress of one page.  Should map everything.
+  ASSERT_TRUE(db().Execute("REPLACE INTO meta VALUES ('mmap_status', 1)"));
+  ASSERT_GT(db().GetAppropriateMmapSize(), kMmapAlot);
+  ASSERT_TRUE(MetaTable::GetMmapStatus(&db(), &mmap_status));
+  ASSERT_EQ(MetaTable::kMmapSuccess, mmap_status);
+
   // Failure status maps nothing.
   ASSERT_TRUE(db().Execute("REPLACE INTO meta VALUES ('mmap_status', -2)"));
   ASSERT_EQ(0UL, db().GetAppropriateMmapSize());
@@ -1593,9 +1599,16 @@ TEST_F(SQLConnectionTest, GetAppropriateMmapSizeAltStatus) {
   EXPECT_EQ(base::IntToString(MetaTable::kMmapSuccess),
             ExecuteWithResult(&db(), "SELECT * FROM MmapStatus"));
 
-  // Also maps everything when kMmapSuccess is in the view.
+  // Also maps everything when kMmapSuccess is already in the view.
   ASSERT_GT(db().GetAppropriateMmapSize(), kMmapAlot);
 
+  // Preload with partial progress of one page.  Should map everything.
+  ASSERT_TRUE(db().Execute("DROP VIEW MmapStatus"));
+  ASSERT_TRUE(db().Execute("CREATE VIEW MmapStatus AS SELECT 1"));

[pavely, 2017/03/17 23:21:35]

nit: When Connection::SetMmapAltStatus creates view it sets column name to
"value" as well. It is not an issue as long as it reads value with "select *".
Might cause test failures if query changes to "select value from MmapStatus".

[Scott Hess - ex-Googler, 2017/03/19 23:47:15]

Good point.  I'm changing the variant a few lines down, too (I think that's
where this one came from, as I'm far too lazy to write new code for something
like this).

+  ASSERT_GT(db().GetAppropriateMmapSize(), kMmapAlot);
+  EXPECT_EQ(base::IntToString(MetaTable::kMmapSuccess),
+            ExecuteWithResult(&db(), "SELECT * FROM MmapStatus"));
+
   // Failure status leads to nothing being mapped.
   ASSERT_TRUE(db().Execute("DROP VIEW MmapStatus"));
   ASSERT_TRUE(db().Execute("CREATE VIEW MmapStatus AS SELECT -2"));