adding MinMaxConstraint and validate for ManageIQ#131

lib/optimist.rb

@@ -81,6 +81,24 @@ def error_message(longargs)
   end
 end
 
+class MinMaxConstraint < Constraint
+  attr_reader :min, :max
+  def initialize(syms, min, max)
+    super(syms)
+    @min = min
+    @max = max
+  end
+  def error_condition(overlap_size)
+    return (min && overlap_size < min) || (max && overlap_size > max)
+  end
+  def error_message(longargs)
+    minmaxmsg = []
+    minmaxmsg << "fewer than #{min}" if min
+    minmaxmsg << "greater than #{max}" if max
+    "cannot have {minmaxmsg.join(' or ')} of these args #{longargs.join(', ')}"
+  end
+end
+
 ## The commandline parser. In typical usage, the methods in this class
 ## will be handled internally by Optimist::options. In this case, only the
 ## #opt, #banner and #version, #depends, and #conflicts methods will
@@ -267,6 +285,12 @@ def either(*syms)
     @constraints << EitherConstraint.new(syms)
   end
 
+  # Validate arguments with min-max, similar to depends/conflicts
+  def validate(min: nil, max: nil, args:)
+    args.each { |sym| raise ArgumentError, "unknown option '#{sym}'" unless @specs[sym] }
+    @constraints << MinMaxConstraint.new(args, min, max)
+  end
+
   ## Defines a set of words which cause parsing to terminate when
   ## encountered, such that any options to the left of the word are
   ## parsed as usual, and options to the right of the word are left

test/optimist/parser_test.rb

@@ -897,6 +897,39 @@ def test_depends
     assert_raises(CommandlineError) { @p.parse %w(--mellow --two --jello --one) }
   end
 
+  def test_validate_minmax
+    [:one, :two, :three, :four, :five].each {|o| @p.opt(o)}
+    @p.validate(min: 2, max: 3, args: [:one, :two, :three, :four])
+    assert_raises(CommandlineError) { @p.parse %w(--one --two --three --four) } # 4 bad
+    assert_raises(CommandlineError) { @p.parse %w(--five --one --two --three --four) } # 4 bad
+    assert_raises(CommandlineError) { @p.parse %w(--three) } # bad
+    @p.parse %w(--one --two --three) # 3 ok
+    @p.parse %w(--two --three --four) # different 3 ok
+    @p.parse %w(--two --four) # 2 ok
+    @p.parse %w(--one --five --four --two) # 3 ok, with extra non-validated arg
+  end
+
+  def test_validate_max
+    [:one, :two, :three, :four, :five].each {|o| @p.opt(o)}
+    @p.validate(max: 2, args: [:one, :two, :three, :four])
+    assert_raises(CommandlineError) { @p.parse %w(--one --two --four) } # 3 bad
+    assert_raises(CommandlineError) { @p.parse %w(--five --one --two --three) } # 3 bad
+    @p.parse %w(--two --four) # 2 ok
+    @p.parse %w(--two) # 1 ok
+    @p.parse %w() # 0 ok
+  end
+
+  def test_validate_min
+    [:one, :two, :three, :four, :five].each {|o| @p.opt(o)}
+    @p.validate(min: 3, args: [:one, :two, :three, :four])
+    @p.parse %w(--four --one --two --three) # 4 ok
+    @p.parse %w(--five --one --two --three) # 3 ok
+    assert_raises(CommandlineError) { @p.parse %w(--two --four) } # 2 bad
+    assert_raises(CommandlineError) { @p.parse %w(--two) } # 1 bad
+    assert_raises(CommandlineError) { @p.parse %w(--five) } # 0 bad
+    assert_raises(CommandlineError) { @p.parse %w() } # 0 bad
+  end
+
   def test_depend_error_messages
     @p.opt :one
     @p.opt "two"