record: 0 und 1 = erste Zeile, negative Nummern zählen vom Ende

test/rdb_test.rb

@@ -5,8 +5,18 @@ require 'pty'
 require_relative '../lib/rdb'
 
 class SelectionTest < RdbCase
-  def test_record_rejects_numbers_below_one_and_junk
-    %w[0 -1 abc 2.5].each do |n|
+  def test_record_zero_and_one_are_the_first_and_negatives_count_from_the_end
+    { '0' => '1', '1' => '1', '2' => '3', '3' => '6', '-1' => '6', '-2' => '3', '-3' => '1', '+2' => '3' }.each do |n, item|
+      assert_equal [[item]], data(rdb('record', n, file: 'owners')).map { |r| r.first(1) }, "record #{n}"
+    end
+  end
+
+  def test_record_beyond_either_end_is_an_empty_table
+    %w[4 9 -4 -9].each { |n| assert_equal [], data(rdb('record', n, file: 'owners')), "record #{n}" }
+  end
+
+  def test_record_rejects_junk
+    %w[abc 2.5 1e3].each do |n|
       out, err, st = run3('record', n, stdin: File.read(File.join(@dir, 'owners')))
       refute st.success?, "record #{n} should fail"
       assert_equal '', out
@@ -14,11 +24,6 @@ class SelectionTest < RdbCase
     end
   end
 
-  def test_record_beyond_the_end_is_an_empty_table
-    assert_equal [], data(rdb('record', '9', file: 'owners'))
-    assert_equal [%w[6 cy]], data(rdb('record', '3', file: 'owners'))
-  end
-
   def test_row_numeric_condition
     out = rdb('row', 'Cost > 5', file: 'inventory')
     assert_equal %w[3 6 7], data(out).map(&:first)