Validate fill batch size

lib/pgslice/cli/fill.rb

@@ -9,6 +9,11 @@ class CLI
     option :where, desc: "Conditions to filter"
     option :sleep, type: :numeric, desc: "Seconds to sleep between batches"
     def fill(table)
+      batch_size = options[:batch_size]
+      unless batch_size.is_a?(Numeric) && batch_size.to_i == batch_size && batch_size.positive?
+        abort "Batch size must be a positive integer"
+      end
+
       table = create_table(table)
       source_table = create_table(options[:source_table]) if options[:source_table]
       dest_table = create_table(options[:dest_table]) if options[:dest_table]
@@ -64,7 +69,6 @@ def fill(table)
 
       starting_id = max_dest_id
       fields = source_table.columns.map { |c| quote_ident(c) }.join(", ")
-      batch_size = options[:batch_size]
 
       i = 1
       batch_count = ((max_source_id - starting_id) / batch_size.to_f).ceil

test/fill_validation_test.rb

@@ -0,0 +1,27 @@
+require "minitest/autorun"
+require_relative "../lib/pgslice"
+
+PgSlice::CLI.exit_on_failure = false
+
+class FillValidationTest < Minitest::Test
+  class TableSetupReached < StandardError; end
+
+  def test_rejects_invalid_batch_sizes_before_table_or_database_access
+    [0, -1, 0.5, 1.5].each do |batch_size|
+      cli = PgSlice::CLI.allocate
+      cli.define_singleton_method(:options) { {batch_size: batch_size} }
+      cli.define_singleton_method(:create_table) { |_| raise TableSetupReached }
+
+      error = assert_raises(Thor::Error) { cli.fill("events") }
+      assert_equal "Batch size must be a positive integer", error.message
+    end
+  end
+
+  def test_accepts_positive_integer_batch_size_before_table_setup
+    cli = PgSlice::CLI.allocate
+    cli.define_singleton_method(:options) { {batch_size: 10} }
+    cli.define_singleton_method(:create_table) { |_| raise TableSetupReached }
+
+    assert_raises(TableSetupReached) { cli.fill("events") }
+  end
+end