From d14da793340ca49c0049257af892a204cba43092 Mon Sep 17 00:00:00 2001
From: Jon Leighton <j@jonathanleighton.com>
Date: Fri, 28 Sep 2012 18:07:25 +0100
Subject: [PATCH] Add an explicit test for hot compatibility

---
 .../test/cases/hot_compatibility_test.rb      | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 activerecord/test/cases/hot_compatibility_test.rb

diff --git a/activerecord/test/cases/hot_compatibility_test.rb b/activerecord/test/cases/hot_compatibility_test.rb
new file mode 100644
index 0000000000..96e581ab4c
--- /dev/null
+++ b/activerecord/test/cases/hot_compatibility_test.rb
@@ -0,0 +1,54 @@
+require 'cases/helper'
+
+class HotCompatibilityTest < ActiveRecord::TestCase
+  self.use_transactional_fixtures = false
+
+  setup do
+    @klass = Class.new(ActiveRecord::Base) do
+      connection.create_table :hot_compatibilities do |t|
+        t.string :foo
+        t.string :bar
+      end
+
+      def self.name; 'HotCompatibility'; end
+    end
+  end
+
+  teardown do
+    @klass.connection.drop_table :hot_compatibilities
+  end
+
+  test "insert after remove_column" do
+    # warm cache
+    @klass.create!
+
+    # we have 3 columns
+    assert_equal 3, @klass.columns.length
+
+    # remove one of them
+    @klass.connection.remove_column :hot_compatibilities, :bar
+
+    # we still have 3 columns in the cache
+    assert_equal 3, @klass.columns.length
+
+    # but we can successfully create a record so long as we don't
+    # reference the removed column
+    record = @klass.create! foo: 'foo'
+    record.reload
+    assert_equal 'foo', record.foo
+  end
+
+  test "update after remove_column" do
+    record = @klass.create! foo: 'foo'
+    assert_equal 3, @klass.columns.length
+    @klass.connection.remove_column :hot_compatibilities, :bar
+    assert_equal 3, @klass.columns.length
+
+    record.reload
+    assert_equal 'foo', record.foo
+    record.foo = 'bar'
+    record.save!
+    record.reload
+    assert_equal 'bar', record.foo
+  end
+end
-- 
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