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rails--rails/activerecord/test/cases/attribute_set_test.rb
Sean Griffin be9b68038e Introduce ActiveRecord::Base#accessed_fields
This method can be used to see all of the fields on a model which have
been read. This can be useful during development mode to quickly find
out which fields need to be selected. For performance critical pages, if
you are not using all of the fields of a database, an easy performance
win is only selecting the fields which you need. By calling this method
at the end of a controller action, it's easy to determine which fields
need to be selected.

While writing this, I also noticed a place for an easy performance win
internally which I had been wanting to introduce. You cannot mutate a
field which you have not read. Therefore, we can skip the calculation of
in place changes if we have never read from the field. This can
significantly speed up methods like `#changed?` if any of the fields
have an expensive mutable type (like `serialize`)

```
Calculating -------------------------------------
 #changed? with serialized column (before)
                       391.000  i/100ms
 #changed? with serialized column (after)
                         1.514k i/100ms
-------------------------------------------------
 #changed? with serialized column (before)
                          4.243k (± 3.7%) i/s -     21.505k
 #changed? with serialized column (after)
                         16.789k (± 3.2%) i/s -     84.784k
```
2015-01-20 14:42:15 -07:00

201 lines
6.8 KiB
Ruby

require 'cases/helper'
module ActiveRecord
class AttributeSetTest < ActiveRecord::TestCase
test "building a new set from raw attributes" do
builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
assert_equal 1, attributes[:foo].value
assert_equal 2.2, attributes[:bar].value
assert_equal :foo, attributes[:foo].name
assert_equal :bar, attributes[:bar].name
end
test "building with custom types" do
builder = AttributeSet::Builder.new(foo: Type::Float.new)
attributes = builder.build_from_database({ foo: '3.3', bar: '4.4' }, { bar: Type::Integer.new })
assert_equal 3.3, attributes[:foo].value
assert_equal 4, attributes[:bar].value
end
test "[] returns a null object" do
builder = AttributeSet::Builder.new(foo: Type::Float.new)
attributes = builder.build_from_database(foo: '3.3')
assert_equal '3.3', attributes[:foo].value_before_type_cast
assert_equal nil, attributes[:bar].value_before_type_cast
assert_equal :bar, attributes[:bar].name
end
test "duping creates a new hash and dups each attribute" do
builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::String.new)
attributes = builder.build_from_database(foo: 1, bar: 'foo')
# Ensure the type cast value is cached
attributes[:foo].value
attributes[:bar].value
duped = attributes.dup
duped.write_from_database(:foo, 2)
duped[:bar].value << 'bar'
assert_equal 1, attributes[:foo].value
assert_equal 2, duped[:foo].value
assert_equal 'foo', attributes[:bar].value
assert_equal 'foobar', duped[:bar].value
end
test "freezing cloned set does not freeze original" do
attributes = AttributeSet.new({})
clone = attributes.clone
clone.freeze
assert clone.frozen?
assert_not attributes.frozen?
end
test "to_hash returns a hash of the type cast values" do
builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
assert_equal({ foo: 1, bar: 2.2 }, attributes.to_hash)
assert_equal({ foo: 1, bar: 2.2 }, attributes.to_h)
end
test "values_before_type_cast" do
builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Integer.new)
attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
assert_equal({ foo: '1.1', bar: '2.2' }, attributes.values_before_type_cast)
end
test "known columns are built with uninitialized attributes" do
attributes = attributes_with_uninitialized_key
assert attributes[:foo].initialized?
assert_not attributes[:bar].initialized?
end
test "uninitialized attributes are not included in the attributes hash" do
attributes = attributes_with_uninitialized_key
assert_equal({ foo: 1 }, attributes.to_hash)
end
test "uninitialized attributes are not included in keys" do
attributes = attributes_with_uninitialized_key
assert_equal [:foo], attributes.keys
end
test "uninitialized attributes return false for key?" do
attributes = attributes_with_uninitialized_key
assert attributes.key?(:foo)
assert_not attributes.key?(:bar)
end
test "unknown attributes return false for key?" do
attributes = attributes_with_uninitialized_key
assert_not attributes.key?(:wibble)
end
test "fetch_value returns the value for the given initialized attribute" do
builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
attributes = builder.build_from_database(foo: '1.1', bar: '2.2')
assert_equal 1, attributes.fetch_value(:foo)
assert_equal 2.2, attributes.fetch_value(:bar)
end
test "fetch_value returns nil for unknown attributes" do
attributes = attributes_with_uninitialized_key
assert_nil attributes.fetch_value(:wibble) { "hello" }
end
test "fetch_value returns nil for unknown attributes when types has a default" do
types = Hash.new(Type::Value.new)
builder = AttributeSet::Builder.new(types)
attributes = builder.build_from_database
assert_nil attributes.fetch_value(:wibble) { "hello" }
end
test "fetch_value uses the given block for uninitialized attributes" do
attributes = attributes_with_uninitialized_key
value = attributes.fetch_value(:bar) { |n| n.to_s + '!' }
assert_equal 'bar!', value
end
test "fetch_value returns nil for uninitialized attributes if no block is given" do
attributes = attributes_with_uninitialized_key
assert_nil attributes.fetch_value(:bar)
end
test "the primary_key is always initialized" do
builder = AttributeSet::Builder.new({ foo: Type::Integer.new }, :foo)
attributes = builder.build_from_database
assert attributes.key?(:foo)
assert_equal [:foo], attributes.keys
assert attributes[:foo].initialized?
end
class MyType
def type_cast_from_user(value)
return if value.nil?
value + " from user"
end
def type_cast_from_database(value)
return if value.nil?
value + " from database"
end
end
test "write_from_database sets the attribute with database typecasting" do
builder = AttributeSet::Builder.new(foo: MyType.new)
attributes = builder.build_from_database
assert_nil attributes.fetch_value(:foo)
attributes.write_from_database(:foo, "value")
assert_equal "value from database", attributes.fetch_value(:foo)
end
test "write_from_user sets the attribute with user typecasting" do
builder = AttributeSet::Builder.new(foo: MyType.new)
attributes = builder.build_from_database
assert_nil attributes.fetch_value(:foo)
attributes.write_from_user(:foo, "value")
assert_equal "value from user", attributes.fetch_value(:foo)
end
def attributes_with_uninitialized_key
builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
builder.build_from_database(foo: '1.1')
end
test "freezing doesn't prevent the set from materializing" do
builder = AttributeSet::Builder.new(foo: Type::String.new)
attributes = builder.build_from_database(foo: "1")
attributes.freeze
assert_equal({ foo: "1" }, attributes.to_hash)
end
test "#accessed_attributes returns only attributes which have been read" do
builder = AttributeSet::Builder.new(foo: Type::Value.new, bar: Type::Value.new)
attributes = builder.build_from_database(foo: "1", bar: "2")
assert_equal [], attributes.accessed
attributes.fetch_value(:foo)
assert_equal [:foo], attributes.accessed
end
end
end