splittable: klare Fehler für -0 und mehr als 676 Stücke

test/rdb_test.rb

@@ -5,6 +5,21 @@ require 'pty'
 require_relative '../lib/rdb'
 
 class SelectionTest < RdbCase
+  def test_splittable_pieces_and_errors
+    out, = run3('splittable', '-4', 'inventory')
+    assert_equal 4, data(File.read(File.join(@dir, 'inventoryaa'))).size
+    assert_equal 3, data(File.read(File.join(@dir, 'inventoryab'))).size
+    assert_includes File.read(File.join(@dir, 'inventoryab')), "Item\tAmount"
+    _o, err, st = run3('splittable', '-0', 'inventory')
+    refute st.success?
+    assert_match(/usage/, err)
+    write('big', "N\n-\n#{(1..700).to_a.join("\n")}\n")
+    _o, err, st = run3('splittable', '-1', 'big')
+    refute st.success?
+    assert_match(/only 676 names/, err)
+    assert_empty Dir[File.join(@dir, 'bigaa')] # nothing is written when it cannot all be written
+  end
+
   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}"