[Ironruby-core] Code Review: Better error messages

[Jim Deville]

it "coerces string argument with Float() without calling singleton to_f" do    
    s = MathSpecs.string_with_singleton_to_f("0.5", 0.5)
    Math.acos(s).should be_close(Math.acos(0.5), TOLERANCE)
    ScratchPad.recorded.should == nil # to_f should not be called
  end
  
  it "coerces string argument with Float() without calling String#to_f" do    
    MathSpecs.hijack_String_to_f
    begin
      Math.acos("0.5").should be_close(Math.acos(0.5), TOLERANCE)
    ensure
      MathSpecs.reset_String_to_f
    end
  end

These can be rewritten with mocks instead of specialized classes. 

it "coerces string argument with Float() without calling singleton to_f" do    
  s = "0.5"
  s.should_not_receive(:to_f)
  Math.acos(s).should be_close(Math.acos(0.5), TOLERANCE)
End

The second spec is really testing method dispatch, and otherwise is the same thing as this one. Same with:

  it "raises an ArgumentError if the singleton string cannot be directly coerced with Float()" do
    s = MathSpecs.string_with_singleton_to_f("test", 0.5)
    lambda { Math.acos(s) }.should raise_error(ArgumentError)
    ScratchPad.recorded.should == nil # to_f should not be called
  end
   
  it "raises an ArgumentError if the string subclass cannot be directly coerced with Float()" do
    s = MathSpecs.string_subclass_with_to_f("test", 0.5)
    lambda { Math.acos(s) }.should raise_error(ArgumentError)
    ScratchPad.recorded.should == nil # to_f should not be called
  End

JD

-----Original Message-----
From: Shri Borde 
Sent: Friday, January 23, 2009 2:04 PM
To: IronRuby External Code Reviewers; DLR Code Reviews
Cc: ironruby-core at rubyforge.org
Subject: Code Review: Better error messages

  tfpt review "/shelveset:error;REDMOND\sborde"

Microsoft.Scripting:

  Change in DefaultBinder is to make the binder exception processing logic be extensible so that languages can customize the type of exception thrown.

IronRuby:
  
  Improves error reporting in IronRuby by checking the results of the bind failure. This allowed many Math tests to be enabled.
  
  Also, added a DefaultProtocol for to_f. This allowed more Math tests to be enabled as you can now pass the string "1.0" to a function expecting a "Float". I have added test cases for the Float conversion rules in core\math\acos_spec.rb. I have not copied this to the other specs as that would be hard to maintain. We will look at factoring such conversion checks into a utility library so that they will be much easier to use.
  
  Fixes some String bugs - String.#inspect on string subtype should return a string, and passing wrong argument types to Strings#[]= should cause TypeError instead of ArgumentError. This is where I started and it put me in the direction of the fixes above.
  
  Tomas: In RubyBinder.GetTypeName, is there a better way to get to RubyContext?