[8.x] Adds new RefreshDatabaseLazily testing trait (#38861)

* Adds a new `LazyRefreshDatabase` testing trait and a `QueryExecuting` database event.

* Refactor

* Refactor

* Event test

* Naming change

* Switches out event for an array of callbacks

* Refactor

* Refactor

* Refactor

* Refactor

* Refactor

* formatting

* fix doc block

Co-authored-by: Taylor Otwell <taylorotwell@gmail.com>

src/Illuminate/Database/Connection.php

@@ -161,6 +161,13 @@ class Connection implements ConnectionInterface
      */
     protected $pretending = false;
 
+    /**
+     * All of the callbacks that should be invoked before a query is executed.
+     *
+     * @var array
+     */
+    protected $beforeExecutingCallbacks = [];
+
     /**
      * The instance of Doctrine connection.
      *
@@ -641,6 +648,10 @@ public function prepareBindings(array $bindings)
      */
     protected function run($query, $bindings, Closure $callback)
     {
+        foreach ($this->beforeExecutingCallbacks as $beforeExecutingCallback) {
+            $beforeExecutingCallback($query, $bindings, $this);
+        }
+
         $this->reconnectIfMissingConnection();
 
         $start = microtime(true);
@@ -807,6 +818,19 @@ public function disconnect()
         $this->setPdo(null)->setReadPdo(null);
     }
 
+    /**
+     * Register a hook to be run just before a database query is executed.
+     *
+     * @param  \Closure  $callback
+     * @return $this
+     */
+    public function beforeExecuting(Closure $callback)
+    {
+        $this->beforeExecutingCallbacks[] = $callback;
+
+        return $this;
+    }
+
     /**
      * Register a database query listener with the connection.
      *

src/Illuminate/Foundation/Testing/LazilyRefreshDatabase.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace Illuminate\Foundation\Testing;
+
+trait LazilyRefreshDatabase
+{
+    use RefreshDatabase {
+        refreshDatabase as baseRefreshDatabase;
+    }
+
+    /**
+     * Define hooks to migrate the database before and after each test.
+     *
+     * @return void
+     */
+    public function refreshDatabase()
+    {
+        $database = $this->app->make('db');
+
+        $database->beforeExecuting(function () {
+            if (RefreshDatabaseState::$lazilyRefreshed) {
+                return;
+            }
+
+            RefreshDatabaseState::$lazilyRefreshed = true;
+
+            $this->baseRefreshDatabase();
+        });
+
+        $this->beforeApplicationDestroyed(function () {
+            RefreshDatabaseState::$lazilyRefreshed = false;
+        });
+    }
+}

src/Illuminate/Foundation/Testing/RefreshDatabaseState.php

@@ -10,4 +10,11 @@ class RefreshDatabaseState
      * @var bool
      */
     public static $migrated = false;
+
+    /**
+     * Indicates if a lazy refresh hook has been invoked.
+     *
+     * @var bool
+     */
+    public static $lazilyRefreshed = false;
 }

src/Illuminate/Support/Facades/DB.php

@@ -28,6 +28,7 @@
  * @method static void enableQueryLog()
  * @method static void disableQueryLog()
  * @method static void flushQueryLog()
+ * @method static \Illuminate\Database\Connection beforeExecuting(\Closure $callback)
  * @method static void listen(\Closure $callback)
  * @method static void rollBack(int $toLevel = null)
  * @method static void setDefaultConnection(string $name)

tests/Database/DatabaseConnectionTest.php

@@ -406,6 +406,17 @@ public function testLogQueryFiresEventsIfSet()
         $connection->logQuery('foo', [], null);
     }
 
+    public function testBeforeExecutingHooksCanBeRegistered()
+    {
+        $this->expectExceptionMessage('The callback was fired');
+
+        $connection = $this->getMockConnection();
+        $connection->beforeExecuting(function () {
+            throw new Exception('The callback was fired');
+        });
+        $connection->select('foo bar', ['baz']);
+    }
+
     public function testPretendOnlyLogsQueries()
     {
         $connection = $this->getMockConnection();