add test for regression

Gemfile

@@ -1,2 +1,3 @@
 source "https://www.rubygems.org"
+gem 'daru', git: '[email protected]:v0dro/daru.git'
 gemspec

statsample.gemspec

@@ -60,7 +60,8 @@ Gem::Specification.new do |s|
   s.test_files = `git ls-files -- {test,spec,features}/*`.split("\n")
   s.executables = `git ls-files -- bin/*`.split("\n").map { |f| File.basename(f) }
 
-  s.add_runtime_dependency 'daru', '~> 0.1'
+  # TODO: Uncomment later after Daru release contains category data
+  # s.add_runtime_dependency 'daru', '~> 0.1'
   s.add_runtime_dependency 'spreadsheet', '~> 1.1'
   s.add_runtime_dependency 'reportbuilder', '~> 1.4'
   s.add_runtime_dependency 'minimization', '~> 0.2'

test/fixtures/df.csv

@@ -0,0 +1,15 @@
+y,a,b,c,d,e
+0,6,62.1,no,female,A
+1,18,34.7,yes,male,B
+1,6,29.7,no,female,C
+0,4,71,no,male,C
+1,5,36.9,yes,male,B
+0,11,58.7,no,female,B
+0,8,63.3,no,male,B
+1,21,20.4,yes,male,A
+1,2,20.5,yes,male,C
+0,11,59.2,no,male,B
+0,1,76.4,yes,female,A
+0,8,71.7,no,female,B
+1,2,77.5,no,male,C
+1,3,31.1,no,male,B

test/test_fit_model.rb

@@ -0,0 +1,19 @@
+require(File.expand_path(File.dirname(__FILE__) + '/helpers_tests.rb'))
+require 'minitest/autorun'
+
+describe Statsample::FitModel do
+  before do
+    @df = Daru::DataFrame.from_csv 'test/fixtures/df.csv'
+    @df.to_category 'c', 'd', 'e'
+  end
+  context '#df_for_regression' do
+    it 'gives correct dataframe when no interaction' do
+      @formula = 'y~a+e'
+      @vectors = %w[a e_B e_C y]
+
+      @model = Statsample::FitModel.new @formula, @df
+
+      @model.df_for_regression.vectors.to_a.sort.must_equal @vectors.sort
+    end    
+  end
+end