spec: test sort_remove_margin function

spec/sort_remove_margin_spec.rb

@@ -0,0 +1,32 @@
+require 'spec_helper'
+require "#{LKP_SRC}/lib/stats"
+
+describe 'sort_remove_margin' do
+  # MARGIN_SHIFT = 5
+  arr = [*1..70]
+
+  context 'when an input array is empty' do
+    it 'returns an empty array' do
+      expect(sort_remove_margin([])).to eq([])
+    end
+  end
+
+  context 'when an input array is not empty and no max_margin is provided' do
+    it 'sorts the array and remove the margin from both ends' do
+      expect(sort_remove_margin(arr)).to eq([*3..68])
+    end
+  end
+
+  context 'when an input array is not empty and a max_margin is provided' do
+    it 'sorts the array and remove the margin (based on the min of calculated margin and max margin) from both ends' do
+      expect(sort_remove_margin(arr, 1)).to eq([*2..69])
+    end
+  end
+
+  context 'when an input array is not empty and margin value is too large' do
+    it 'returns an empty array' do
+      stub_const('MARGIN_SHIFT', 1)
+      expect(sort_remove_margin(arr)).to eq([])
+    end
+  end
+end