Add SQLite feature test to verify working foreign key support.

sql/sqlite_features_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "sql/connection.h"
 #include "sql/statement.h"
+#include "sql/test/test_helpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/sqlite/sqlite3.h"
 
 // Test that certain features are/are-not enabled in our SQLite.
 
 namespace {
 
 void CaptureErrorCallback(int* error_pointer, std::string* sql_text,
                           int error, sql::Statement* stmt) {
   *error_pointer = error;
@@ skipping 11 matching lines @@
 
     // The error delegate will set |error_| and |sql_text_| when any sqlite
     // statement operation returns an error code.
     db_.set_error_callback(base::Bind(&CaptureErrorCallback,
                                       &error_, &sql_text_));
   }
 
   void TearDown() override {
     // If any error happened the original sql statement can be found in
     // |sql_text_|.
-    EXPECT_EQ(SQLITE_OK, error_);
+    EXPECT_EQ(SQLITE_OK, error_) << sql_text_;
     db_.Close();
   }
 
+  void VerifyAndClearLastError(int expected_error) {
+    EXPECT_EQ(expected_error, error_);
+    error_ = SQLITE_OK;
+    sql_text_.clear();
+  }
+
   sql::Connection& db() { return db_; }
 
  private:
   base::ScopedTempDir temp_dir_;
   sql::Connection db_;
 
   // The error code of the most recent error.
   int error_;
   // Original statement which has caused the error.
   std::string sql_text_;
@@ skipping 48 matching lines @@
 
   ASSERT_TRUE(db().Execute("INSERT INTO foo (x) VALUES ('test')"));
 
   sql::Statement s(db().GetUniqueStatement(
       "SELECT x FROM foo WHERE x MATCH 'te*'"));
   ASSERT_TRUE(s.Step());
   EXPECT_EQ("test", s.ColumnString(0));
 }
 #endif
 
+// Ensure that our SQLite version has working foreign key support with cascade
+// delete support.
+TEST_F(SQLiteFeaturesTest, ForeignKeySupport) {
+  ASSERT_TRUE(db().Execute("PRAGMA foreign_keys=1"));
+  ASSERT_TRUE(db().Execute("CREATE TABLE parents (id INTEGER PRIMARY KEY)"));
+  ASSERT_TRUE(db().Execute(
+      "CREATE TABLE children ("
+      "    id INTEGER PRIMARY KEY,"
+      "    pid INTEGER NOT NULL REFERENCES parents(id) ON DELETE CASCADE)"));
+
+  // Inserting without a matching parent should fail with constraint violation.
+  EXPECT_FALSE(db().Execute("INSERT INTO children VALUES (10, 1)"));
+  VerifyAndClearLastError(SQLITE_CONSTRAINT);
+
+  size_t rows;
+  EXPECT_TRUE(sql::test::CountTableRows(&db(), "children", &rows));
+  EXPECT_EQ(0u, rows);
+
+  // Inserting with a matching parent should work.
+  ASSERT_TRUE(db().Execute("INSERT INTO parents VALUES (1)"));
+  EXPECT_TRUE(db().Execute("INSERT INTO children VALUES (11, 1)"));
+  EXPECT_TRUE(db().Execute("INSERT INTO children VALUES (12, 1)"));
+  EXPECT_TRUE(sql::test::CountTableRows(&db(), "children", &rows));
+  EXPECT_EQ(2u, rows);
+
+  // Deleting the parent should cascade, i.e., delete the children as well.
+  ASSERT_TRUE(db().Execute("DELETE FROM parents"));
+  EXPECT_TRUE(sql::test::CountTableRows(&db(), "children", &rows));
+  EXPECT_EQ(0u, rows);
+}
+
 }  // namespace