Ensure convert_to_sql matcher returns unprepared statements (no "?"…

… placeholder)

spec/matchers/convert_to_sql.rb

@@ -19,7 +19,22 @@
   end
 
   def convert_to_sql(actual)
-    normalize_sql(actual.to_sql)
+    normalize_sql to_unprepared_sql(actual)
+  end
+
+  # In ActiveRecord 4.0 and 4.1, when the adapter supports prepared statements, calling `to_sql` on
+  # a `has_many` association collection proxy returns a statement with "?" instead of the actual foreign key:
+  #
+  #     SELECT "messages".* FROM "messages" WHERE "messages"."author_id" = ?
+  #
+  # Here we ensure we always get the unprepared statement.
+  def to_unprepared_sql(actual)
+    connection = actual.respond_to?(:connection) && actual.connection
+    if connection && connection.respond_to?(:unprepared_statement)
+      connection.unprepared_statement { actual.to_sql }
+    else
+      actual.to_sql
+    end
   end
 
   # Arel < 6 seems to inserts an additionnal (harmless) space before the WHERE clause.