fix: tighten response data validation

Author: kholdrex

lib/irt_ruby/rasch_model.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "irt_ruby/response_data_validator"
+
 module IrtRuby
   # A class representing the Rasch model for Item Response Theory (ability - difficulty).
   # Incorporates:

lib/irt_ruby/response_data_validator.rb

@@ -3,8 +3,6 @@
 module IrtRuby
   # Validates response data accepted by IRT model constructors.
   module ResponseDataValidator
-    VALID_RESPONSES = [0, 1, nil].freeze
-
     module_function
 
     def validate!(data)
@@ -40,12 +38,16 @@ def validate_rows!(data_array)
     def validate_values!(data_array)
       data_array.each_with_index do |row, row_index|
         row.each_with_index do |value, column_index|
-          next if VALID_RESPONSES.include?(value)
+          next if valid_response?(value)
 
           raise ArgumentError,
-                "response data contains invalid value #{value.inspect} at row #{row_index}, column #{column_index}; allowed values are 0, 1, and nil"
+                "response data contains invalid value #{value.inspect} at row #{row_index + 1}, column #{column_index + 1}; allowed values are 0, 1, and nil"
         end
       end
     end
+
+    def valid_response?(value)
+      value.nil? || value.eql?(0) || value.eql?(1)
+    end
   end
 end

lib/irt_ruby/three_parameter_model.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "irt_ruby/response_data_validator"
+
 module IrtRuby
   # A class representing the Three-Parameter model (3PL) for Item Response Theory.
   # Incorporates:

lib/irt_ruby/two_parameter_model.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "irt_ruby/response_data_validator"
+
 module IrtRuby
   # A class representing the Two-Parameter model (2PL) for IRT.
   # Incorporates:

spec/spec_helper.rb

@@ -19,6 +19,11 @@
     expect { described_class.new([[1, 2], [0, nil]]) }.to raise_error(ArgumentError, /invalid value 2/)
   end
 
+  it "rejects float response values that compare equal to allowed integers" do
+    expect { described_class.new([[0.0]]) }.to raise_error(ArgumentError, /invalid value 0\.0/)
+    expect { described_class.new([[1.0]]) }.to raise_error(ArgumentError, /invalid value 1\.0/)
+  end
+
   it "rejects non-numeric truthy, falsey, and string responses" do
     expect { described_class.new([[1, "1"], [false, nil]]) }.to raise_error(ArgumentError, /invalid value/)
   end