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Testing Command-Line Interface Functionality in MailCatcher

This test suite validates the command-line interface functionality of MailCatcher, focusing on version display and help command behaviors. It ensures proper output and exit handling for essential CLI commands.

Test Coverage Overview

The test suite provides focused coverage of MailCatcher’s command-line interface commands. It specifically tests the –version and –help flags, verifying correct version information display and help text output.

Version command output validation
Help command content verification
Command execution and process output handling

Implementation Analysis

The testing approach utilizes RSpec’s system command execution and output matching capabilities. It leverages string matchers and process output capture to validate CLI behavior.

RSpec context blocks for command organization
System command execution testing
Output string matching patterns
Process stdout capture validation

Technical Details

RSpec testing framework
System command execution
String matchers and pattern matching
Process output capture mechanisms
Version string interpolation

Best Practices Demonstrated

The test suite demonstrates clean and efficient CLI testing practices, with well-organized test contexts and specific expectations.

Isolated command testing
Clear context separation
Specific output validation
Proper process handling
Version consistency checking

sj26/mailcatcher

spec/command_spec.rb

            
require "spec_helper"

RSpec.describe "mailcatcher command" do
  context "--version" do
    it "shows a version then exits" do
      expect { system %(mailcatcher --version) }
        .to output(a_string_including("MailCatcher v#{MailCatcher::VERSION}"))
        .to_stdout_from_any_process
    end
  end

  context "--help" do
    it "shows help then exits" do
      expect { system %(mailcatcher --help) }
        .to output(a_string_including("MailCatcher v#{MailCatcher::VERSION}") & a_string_including("--help") & a_string_including("Display this help information"))
        .to_stdout_from_any_process
    end
  end
end