Add bare bones console application for filtering CSV

bin/csv-filter

@@ -0,0 +1,26 @@
+#!/usr/bin/env ruby
+
+require 'optparse'
+require 'csv'
+
+options = {}
+
+parser = OptionParser.new
+
+parser.version = CSV::VERSION
+parser.banner = <<-BANNER
+Usage: #{parser.program_name} [options]
+
+  Reads and parses the CSV text content of the standard input per the given input options.
+  From that content, generates CSV text per the given output options
+  and writes that text to the standard output.
+
+BANNER
+
+parser.separator('Generic Options')
+parser.separator(nil)
+
+parser.parse!
+
+CSV.filter(**options) do |row|
+end

test/csv/csv-filter/test_csv_filter.rb

@@ -0,0 +1,102 @@
+# frozen_string_literal: false
+
+require_relative '../helper'
+
+require 'csv'
+
+class TestFilter < Test::Unit::TestCase
+
+  # Some rows data (useful as default).
+  Rows = [
+    %w[aaa bbb ccc],
+    %w[ddd eee fff],
+  ]
+
+  # Return CSV string generated from rows array and options.
+  def make_csv_s(rows: Rows, **options)
+    CSV.generate(**options) do|csv|
+      rows.each do |row|
+        csv << row
+      end
+    end
+  end
+
+  # Return filepath of file containing CSV data.
+  def csv_filepath(csv_in_s, dirpath, option_sym)
+    filename = "#{option_sym}.csv"
+    filepath = File.join(dirpath, filename)
+    File.write(filepath, csv_in_s)
+    filepath
+  end
+
+  # Return stdout and stderr from CLI execution.
+  def run_csv_filter(filepath, cli_option_names = [])
+    top_dir = File.join(__dir__, "..", "..", "..")
+    command_line_s = [
+      Gem.ruby,
+      "-I",
+      File.join(top_dir, "lib"), 
+      File.join(top_dir, "bin", "csv-filter"),
+      * cli_option_names,
+      filepath,
+    ].join(' ')
+    Tempfile.create("stdout", mode: File::RDWR) do |stdout|
+      Tempfile.create("stderr", mode: File::RDWR) do |stderr|
+        status = system(command_line_s, {1 => stdout, 2 => stderr})
+        stdout.rewind
+        stderr.rewind
+        [stdout.read, stderr.read]
+      end
+    end
+  end
+
+  # Return results for CLI-only option (or invalid option).
+  def results_for_cli_option(option_name)
+    cli_out_s = ''
+    cli_err_s = ''
+    Dir.mktmpdir do |dirpath|
+      sym = option_name.to_sym
+      filepath = csv_filepath('', dirpath, sym)
+      cli_out_s, cli_err_s = run_csv_filter(filepath, [option_name])
+    end
+    [cli_out_s, cli_err_s]
+  end
+
+  # Get and return the actual output from the API.
+  def get_via_api(csv_in_s, **api_options)
+    cli_out_s = ''
+    CSV.filter(csv_in_s, cli_out_s, **api_options) {|row| }
+    cli_out_s
+  end
+
+  # Test for invalid option.
+
+  def test_invalid_option
+    cli_out_s, cli_err_s = results_for_cli_option('-Z')
+    assert_equal("", cli_out_s)
+    assert_match(/OptionParser::InvalidOption/, cli_err_s)
+  end
+
+  # Test for no options.
+
+  def test_no_options
+    csv_in_s = make_csv_s
+    cli_out_s = get_via_api(csv_in_s)
+    assert_equal(csv_in_s, cli_out_s)
+  end
+
+  # Tests for general options.
+
+  def test_option_h
+    cli_out_s, cli_err_s = results_for_cli_option('-h')
+    assert_equal("Usage: csv-filter [options]\n", cli_out_s.lines.first)
+    assert_equal('', cli_err_s)
+  end
+
+  def test_option_v
+    cli_out_s, cli_err_s = results_for_cli_option('-v')
+    assert_match(/\d+\.\d+\.\d+/, cli_out_s)
+    assert_equal('', cli_err_s)
+  end
+
+end